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Frequently Asked Questions

In March of 1992, the FDA Division of Regulatory Guidance issued an opinion letter after 18 months of study, that a product “made by the removal of non-protein components such as lactose, water, and minerals from skim milk by the ultrafiltration procedure, thereby concentrating the protein components to higher levels” could be called a milk protein concentrate. In the same writing, the FDA supplied a further description by stating that the milk protein concentrate should contain protein representative “of all the fractions of milk proteins in the same ratio as they are found naturally occurring in milk.” Although there is no official, legal identity for a milk protein concentrate in the Code of Federal Regulations, the above definition is the FDA’s intention for an identity of MPC.

There are some MPC’s being offered in the USA today that do not fit within the identity stated above. There are MPC’s being offered today that are mixtures of caseinates and whey protein concentrates. There are also mixtures of caseinates and skim milk that are being offered as MPC. Be very careful to ensure that your ingredient is true, filtered MPC within the spirit of the FDA opinion.

Yes. Flavor, texture, and functional properties of MPC/MPI powders can vary between manufacturers. Factors such as milk freshness, aggregate exposure to heat, and processing temperatures will all play an important role in sensory quality, water solubility, and functional properties of powders. IdaPro MPC/MPIs are manufactured from the freshest milk and are exposed to a minimum of heat during processing. As a result, IdaPro MPC/MPI powders display superior properties compared to other powders.


Cow’s milk contains a balance of the casein proteins and the soluble serum proteins, more commonly known as whey proteins. Typically, milk from Idaho Milk Products' cows will contain approximately 82% casein and 18% whey proteins along with a small amount of Non-Protein Nitrogen compounds. A well manufactured MPC/MPI will contain a ratio of casein to whey proteins of about 82% casein and 18% whey proteins. Much of the non-protein nitrogen compounds (e.g., urea, creatinine, ammonia compounds, and uric acid) are separated away from the casein and whey proteins during ultrafiltration and can be found in the milk permeate.

The casein proteins derive their name from the Latin word for cheese, “caseus”. It’s easy to surmise that caseins are the group of milk proteins that precipitate out as a curd during cheese manufacture. Whey proteins are so named because they are the group of proteins that remain soluble during cheese manufacture and are found in the cheese whey. In a well manufactured MPC/MPI, the caseins will be present in their natural, native milk structure, known as a micelle. A well manufactured MPC/MPI will also contain a high quantity of whey proteins that have not been damaged (denatured) by heat or chemicals.

The word “micelle” is a chemical term. It is used to describe the structure that certain very large molecules will form when dispersed in a solvent. Believe it or not, water is considered to be a solvent (chemicals are made soluble in water). Very large molecules are considered to be too large to be truly soluble in water. Instead, these large molecules will form structures that allow them to remain suspended in water as if they are soluble. The dispersion of these large structures in water is known as a colloidal suspension. The structures that allow large molecules to remain colloidally suspended in water are termed micelles. Under an electron microscope, micelles often look like little spheres. In the case of casein, the parts of the casein molecules that have an affinity for water form the outside of the casein micelle. Conversely, the parts of the casein molecule that are repelled by water form the inner core of the micelle spheres.

When casein molecules are manufactured by a mammal, they are manufactured in water (cow’s milk is 88% water). As the casein molecules are formed, they begin folding up into a spherical micelle structure so that the casein proteins can remain suspended indefinitely in the milk water. Along with the casein proteins in the micelle, important milk minerals, such as calcium and phosphorous also become bound inside the micelle. The micelle structure of casein is its natural structure. The micelle structure can be easily disrupted or changed – by addition of acid or alkali to milk – or by extreme heat exposure. Products such as acid casein, rennet casein and any and all caseinates no longer contain casein in its micelle form. These products are all manufactured in such a way that the micelle colloidal suspension in milk has been destroyed. Once a casein micelle is destroyed, it will not re-form. Over the years many attempts have been made to rebuild casein micelles after they have been destroyed. To date, nobody has been successful.

Casein in its micellar form is a unique molecular structure. When we consume micellar form casein, a “bolus” (a large curd) is formed in our stomach as the micellar casein reacts with gastric juices in the stomach. The bolus takes on a unique structure also. Our stomachs and upper intestines produce enzymes to help speed up digestion of food. Some of these enzymes are “site specific” … meaning that they will only act on specific sites of a molecule when that molecule is in a specific structure. These specific enzymes fit into molecular structures much as a specific key fits into a specific lock. Specific digestive enzymes will act on casein micelles to produce bioactive peptides from micellar casein. Some of these peptides will have immunomodulatory properties. Others will have antibacterial properties. Examples of peptides produced from consumption of micellar casein are:

  • Glycomacropeptide (GMP) – produced when kappa-casein is hydrolyzed at one specific peptide bond, between amino acids 105 and 106. The smaller peptide that is formed from amino acids 106 through 169 is GMP. When the stomach detects the formation of GMP, a hormonal cascade begins. The body produces cholecystokinin (CKK) a chemical that signals the brain of satiety and suppresses appetite. GMP has also been shown to enhance the absorption of calcium and zinc. GMP has been shown to inhibit platelet aggregation in our veins and arteries, thereby helping to prevent arteriosclerosis.
  • Casomorphins – These are peptides cleaved from micellar casein during digestion that elicit an opioid effect in the body. They have been shown to travel to the brain and can have a calming, tranquilizing effect. They have also been shown to be antihypertensive and, as such, are under investigation as a natural blood pressure control agent. Casomorphins can also act to slow motility of the small intestine, thereby allowing food to linger longer for maximum absorption of nutrients in the food.
  • Casein-Phospho-Peptide (CPP) – These peptides contain high levels of calcium and phosphorous. They are easily absorbed into the bloodstream and, therefore, carry large quantities of calcium and phosphorous into the bloodstream. Since calcium (of the form as found in milk) and phosphorous are the building blocks of our skeletal system, it can be said that CPP helps to build strong bones. In Asia, CPP is used as a preventative against osteoporosis.

Along with the bioactive peptides that form when micellar casein is consumed, there are other study proven benefits. Micellar casein is the only protein that has ever been shown to be anticatabolic (Boire et. al. 1997) – meaning that micellar form casein will help prevent oxidative breakdown of muscle tissue during and after intense exercise. Consumption of micellar casein results in prolonged periods (up to 7 hours) of elevated amino acids in the bloodstream, thereby allowing the body to repair and build muscle tissue after exercise for prolonged periods of time.

No. The metabolic benefits attributed to micellar casein consumption will not automatically transfer over to casein/caseinate consumption. As stated in the response above, many of the digestive enzymes are site specific and require a certain structure to perform. Acid casein and/or rennet casein have already been precipitated as a curd from milk as part of their manufacture. The casein micelle structure has already been destroyed in acid casein, rennet casein, and caseinates before you consume them. Therefore, when casein or caseinates hit the gastric juices in the stomach, they may or may not form a “bolus” structure that is compatible with the site specific enzymes. There is no guarantee that the array of bioactive peptides and anticatabolic activity of micellar casein will be exhibited after consumption of casein and/or caseinates.

Casein is manufactured by adding acid to warm skim milk. As the pH of the skim milk lowers to the range of 4.2 to 4.6, the casein precipitates out of the skim milk as a curd. The casein curd is then washed repeatedly with acidified fresh water to “purify” the casein (wash away unwanted, occluded milk solids such as fat and lactose). Because the casein curd is kept at an acid pH, the milk minerals are leached out of the protein. The result is a relatively pure protein curd (96% protein on a dry basis).

This casein curd, however, is not very useful in food products. Acid casein (as the curd is known) is insoluble in water, behaving much like sand. In order to make the casein curd more useful in food products, the acid casein curd is reacted with a strong alkali to result in an almost neutral protein product termed a caseinate. The type of alkali used to neutralize the acid casein curd will determine what type of caseinate is produced. For example, reacting acid casein curd with sodium hydroxide (to a pH of about 6.8) results in the formation of sodium caseinate. Reacting acid casein curd with calcium oxide or calcium hydroxide (to pH 6.8 to 7.6) results in the formation of calcium caseinate. Sodium caseinate is the most water soluble form of caseinate. Sodium caseinate typically forms high viscosity water dispersions, has an amber color in water, and imparts a “glue-like sodium” flavor. Sodium caseinate is the basis of simple glues. Calcium caseinate forms a low viscosity, opaque, off white dispersion in water. Calcium caseinate is usually the least water soluble of the caseinates and tends to sediment out of suspension within hours of being mixed into water. Whereas sodium caseinate will exhibit a smooth mouthfeel when dispersed in water, calcium caseinate will exhibit a slightly gritty or grainy mouthfeel. There are also sodium calcium caseinates, calcium sodium caseinates, and even calcium ammonium caseinates. The levels of each mineral are determined by the ratios of alkali used in the caseinate manufacture. The higher the sodium content, the higher the viscosity and water solubility. The higher the calcium content, the lower the water viscosity and solubility. Potassium caseinate possesses properties similar to sodium caseinate and magnesium caseinate possesses properties similar to calcium caseinate.

The process of manufacturing acid casein and/or caseinates does extensive damage to the proteins. Some of the “damage” causes off flavors to develop. Dried acid casein, for example has a very strong, objectionable odor and flavor that is difficult to cover up. Although much work is performed to decrease or eliminate these objectionable casein flavors when manufacturing caseinates, most people would agree that caseinates still possess strong objectionable, flavors – usually these flavors are described as “cow-ey”, “barny”, “gluey”, and “livestock”.

Milk Protein Concentrate and Isolate, on the other hand, is manufactured by a gentle process. At Idaho Milk Products, our MPC/MPI is manufactured at cold temperatures. We do not add chemicals* to the milk and the milk does not undergo pH changes. The milk protein is separated out of skim milk using filtration techniques. MPC/MPI typically contains high levels of milk calcium, phosphorous, potassium, and magnesium. These minerals are bound to the protein. Milk protein concentrate and isolate typically have no odor and a very bland flavor profile. Milk protein concentrate and isolate typically contain about 82% casein and 18% whey proteins. These proteins are present in MPC/MPI in the natural (Native), undamaged (undenatured) state.

*see FAQ titled "Are any additives used during the filtration process when producing MPI-85 Low Lactose?"

In most cases, yes, you can use IdaPro MPC/MPI to replace casein and/or caseinates in food formulations.

Obviously, since MPC/MPI forms water dispersions that are most similar in appearance to calcium caseinate, one can easily substitute MPC/MPI into any calcium caseinate application. Usually, substituting MPC/MPI for calcium caseinate will result in an improvement in food product quality as MPC/MPI is more water soluble/suspendable than calcium caseinate, imparts a creamier mouth feel, and has a more preferable flavor profile compared to calcium caseinate. Many people use calcium sodium caseinates to gain a better mouth feel and better water solubility (compared to calcium caseinate). MPC/MPI is very comparable to the best calcium sodium caseinates and even many sodium calcium caseinates in solution appearance, suspension stability, mouth feel, and viscosity. MPC/MPI also has a cleaner, blander flavor than calcium sodium caseinate or sodium calcium caseinate. Even though sodium caseinate is the least similar to MPC/MPI, one can still replace sodium caseinate with MPC/MPI in many applications. MPC/MPI has been used to replace or extend sodium caseinate in coffee whiteners, whipped toppings, and cheese analog products.

Do you produce any MPI where the casein to whey ratio is higher than that found in natural milk?

If you’re confused, you’re not alone! When speaking of protein contents, the only protein content (powder or liquid) that should concern a food processor is the “as is” protein content. Many protein manufacturers try to make their protein powder compositions look better by providing a “dry basis” protein content – the percent of protein based on total solids present, excluding water. All spray dried powders, however, contain some water content – usually about 4% to 5%. Therefore, a stated “dry basis” protein content of 90% in the average powder means that 90% of the 95% solids in that powder is protein (90% x 95%) which equals values anywhere from 85.5% to about 86.5% protein that is in the powder as you will be using it (otherwise known as the “as is” protein content). You want to know the “as is” protein content of the powder that you will be using because that is the protein content “as you will be using” the powder. When you compare protein contents of powders, be sure to compare the “as is” values. Do not compare a 90% “dry basis” value with an 85% “as is” value and think that you’re getting a much better buy with the 90%. Chances are that powder really only has an “as is” protein content of about 86%.

There is very little difference between an MPC and an MPI—If both are truly filtered products…ultrafiltration, microfiltration, etc. A truly filtered MPI (90% protein dry basis—about 86% protein “as is” basis) contains a higher protein content than an MPC 80 (80% protein minimum “as is” basis) or MPC 85 (82.5% protein minimum “as is” basis). An MPI will have a higher protein content (anywhere from 3.5% to 6%) because it contains that much less lactose (MPI usually contains about 1% to 2% lactose). In most food ingredient functional applications, there is little discernible difference between a truly filtered MPI and an MPC 80 or 85. Most companies purchase MPI because they desire a “lactose free” label declaration. There are, however, numerous Milk Protein Isolates (MPI) that are manufactured in much the same manner as casein/caseinates. They are nothing like a true MPC or a truly filtered MPI. These types of proteins are also called Milk Protein Isolates. These types of MPIs are usually manufactured by precipitating casein and/or casein/whey protein aggregates from skim milk and washing the curd to purify the protein—much the same process as casein/caseinate manufacture. In fact, most of the Milk Protein Isolates on the market today are not much different from a caseinate with a little bit of whey protein mixed in. In actual fact, there is no legal definition anywhere in the world for a Milk Protein Isolate. The name was derived from proposed Food Codex Alimentarius Guidelines for protein products wherein a protein concentrate was defined as a powder having a protein content between 40% and 89% and a protein isolate powder would have a minimum protein content of 90%. Under these proposed guidelines, the protein content is a “dry basis” protein content, meaning that an MPI powder need only have an “as is” protein content of about 86% to be called an “isolate.” There are many manufacturers of MPI in other countries who blend caseinates with whey proteins and call the blends MPI. The majority of MPIs available today (those that are manufactured with a precipitation step in their processing) do not accurately reflect the FDA’s opinion of a milk protein—having the same proteins as they are naturally found in milk and in the same ratios as they are naturally found in milk. The majority of MPIs for sale today do not contain all of the whey proteins as found in milk and certainly not in the ratios as naturally found in milk. Be very careful to ask questions about the protein that you are buying. Was it manufactured solely from a filtration process or was precipitation and alkali added anywhere during the processing?

D and L refer to the confirmation, or orientation, of molecules that make up amino acids that form proteins.  While amino acid confirmation is difficult to determine in a lab, biological systems such as the human body are able to easily differentiate these two forms and will only use amino acids in the L-conformation to form needed proteins.  The amino acids found in almost all naturally occurring proteins, including milk protein, are entirely in the L confirmation.  The D form of amino acids is only found in a few isolated instances which mainly consist of short peptide chains of bacterial cell walls and certain peptide antibiotics.

Since all amino acids found on any of the naturally occurring food proteins are of the L-form and are bound together on the protein chain via peptide bonds, it would be impossible to convert any of the L-amino acids to a D-form without first tearing apart the protein during processing so that the amino acids are no longer bound to one another. At that point, it would no longer be considered a protein, but would instead be a pool of free amino acids. There exists no known processing technique that can cause the L-form amino acids which are bound together on an intact protein chain to spontaneously convert to the D-form. The filtration techniques used to manufacture MPC and MPI are of a sufficient passive nature that the MPC and MPI proteins remain intact throughout processing and the amino acids all remain in the preferred L-form. Anyone who teaches that the processes for making a milk protein isolate yield isolates that contain D-form amino acids, thereby resulting in an inferior quality protein, is making grossly inaccurate and patently false statements that have no basis in science.

By the method used to run an amino acid assay, the amide group on glutamine is sheared off during the breaking of peptide bonds, changing the glutamine into glutamic acid. They are not the same thing...but by an amino acid assay, glutamine always shows up as glutamic acid. Unfortunately, it doesn't help that the body cannot convert glutamic acid back to glutamine. Our best estimate of the glutamine level in our product is 5.7-6.7g glutamine per 100g of MPI-85 (assuming 82/18 casein to whey ratio).

The term, Milk Protein Concentrate, was modeled after the already existing name for protein that had been concentrated from cheese whey by ultrafiltration, Whey Protein Concentrate (WPC). In spite of the fact that MPC is significantly different from WPC, many people today continue to confuse the two. As per the FDA opinion, a Milk Protein Concentrate should contain all of the proteins that are naturally found in milk and these proteins should be found in an MPC in the same ratios as they are naturally found in milk. Since cow’s milk contains approximately 80% to 82% casein and only 18% to 20% whey proteins, it’s easy to understand that MPC contains only a small amount of whey protein. WPC (and also WPI), on the other hand, contains 100% whey proteins…by definition, there is no casein present in WPC. MPC forms a milk white suspension when dispersed in water. WPC (and WPI) form somewhat clear, brownish tinted dispersions in water. Aqueous dispersions of MPC have a bland or creamy flavor. Aqueous dispersions of WPC tend to have a slightly astringent flavor due to the high levels of sodium, potassium, and chlorine. Do not confuse MPC with WPC or WPI. They are significantly different in all respects—nutritionally, compositionally, and functionally.

If one is talking about nutritional quality, it is difficult to accurately assess the nutritional quality of a single protein when it is mixed with other nutrients in a consumer product. For that reason, protein nutritional quality is usually assessed on a single protein without any additional nutrients present. Such assays include Relative Protein Efficiency Ratio, Biological Value, Net Protein Utilization, Net Nitrogen Utilization, and Protein Digestibility Corrected Amino Acid. Most, or all, of these methods, however, have encountered criticism in scientific circles because of their inherent bias towards certain protein groups and their lower relative scores for protein groups that would otherwise prove to have greater nutritional value than assay scores indicate. In discussing protein nutritional quality, we need to think about functions of a protein in relation to its ability to achieve desired metabolic actions in the body. Traditionally, protein nutritional quality has been limited to the context of a protein's ability to provide specific patterns of amino acids to satisfy the body’s demands for synthesis of protein as measured by lab animal growth or by nitrogen balance in humans. As new research reveals the increasingly complex roles for dietary protein and those minerals that are chelated to dietary proteins, beyond a role in maintaining body protein mass, the concept of protein nutritional quality must expand to incorporate these other metabolic functions into the concept of protein nutritional quality. Dietary proteins are known to assist in the regulation of body composition, bone health, immune system function, gastrointestinal function, maintenance of bacterial flora, glucose homeostasis, cell signaling, and satiety. The evidence available to date suggests that protein consumption becomes significant not only at the minimum Recommended Dietary Allowance level required for metabolic maintenance but also at higher daily protein intakes. Currently accepted methods for measuring protein nutritional quality do not consider the diverse functions that dietary proteins play in the human body. As research continues to evolve in illuminating protein's function for optimal health at higher intakes, there is also need to continue to explore new, more accurate methods for measuring protein quality. Milk proteins play significant roles in human body metabolism compared to other available dietary proteins. Current protein nutritional quality assays do not accurately portray the entire metabolic value of milk proteins in the human body.

Protein quality in a consumer product can also be expressed as a protein’s ability to be used as a functional ingredient in consumer products. Not all proteins are created the same. Commercially available proteins will vary significantly in their solubility, aqueous viscosity, water binding, gelation, film forming, emulsification, whipping, and heat stability. Obviously, protein solubility is critical in applications wherein texture or suspension stability is important. Use of proteins with varying viscosities, water binding, or gelation characteristics allow food companies to formulate a wide variety of food products. One can take advantage of protein film forming properties to formulate shelf stable high fat food products and freeze-thaw stable whipped toppings and other frozen desserts. Heat stable proteins can be used to manufacture high protein, shelf stable consumer products. Milk proteins can be manufactured with varying functional properties to meet the needs of food companies across the spectrum. Contact your Idaho Milk Products sales representative today to find out if there is a milk protein available for your application requirements.

To make a claim about lactose in a food product, one is making a nutrient content claim. A nutrient content claim on a food label characterizes how much of that particular nutrient is present in the food. It does not link the nutrient with a specific disease or health condition. Nutrient content claims can only be made if a food product meets the criteria for a content claim as set by the FDA. Absolute nutrient content claims, i.e., referring to a specific nutrient content in a single food, do not make comparisons of nutrient content to other food products. Absolute nutrient claims use phrases such as ”high,” “low,” or “free.” Absolute claims are well defined in the FDA’s nutrient content claim regulations contained in 21CFR 101.13 (see also FDA Guidance Document, Guidance for Industry: A Food Labeling Guide (8. Claims) dated January, 2013, to better understand the regulations for making a nutrient content claim).

From the Guidance document:

“N24. May a food that is normally low in or free of a nutrient bear a ”low” or “free” claim if it has an appropriate disclaimer (e.g.,fat-free broccoli)?

Answer: No. Only foods that have been specially processed, altered, formulated, or reformulated so as to lower the amount of nutrient in the food, remove the nutrient from the food, or not include the nutrient in the food may bear such a claim (e.g., "low sodium potato chips"). Other foods may only make a statement that refers to all foods of that type (e.g., "corn oil, a sodium-free food" or "broccoli, a fat-free food"). 21 CFR 101.13(e)(1)-(2)

N25. When is a formulated food considered to be specially processed and permitted to bear a "low" or "free" claim?

Answer: If a similar food would normally be expected to contain a nutrient, such as sodium in canned peas, and the labeled food is made in such a manner that it has little or none of the nutrient, then the food is considered specially processed and may bear a "free" or a "low" claim. 21 CFR 101.13(e)(1)”

It does need to be mentioned that there is no specific FDA definition for the terms “lactose free,” “low lactose,” or “lactose reduced.” A “lactose-free” or “low-lactose” product may still contain low levels of lactose. The most useful guidance for product labels with regards to determining lactose content is best described by the FTC (Federal Trade Commission). This organization’s principal mission is to protect consumers against unfair or deceptive acts or practices in commerce including but not limited to advertising and marketing claims. These general guidelines provided by the FTC are as follows in the case of lactose:

  • Lactose “Free” implies that a food has the least possible amount of lactose…either it contains no lactose or it contains less than 0.5 grams of lactose, the rest of the lactose having been removed, per suggested serving size.
  • “Low” Lactose means the food contains more than 0.5 grams of lactose per suggested serving size but contains significantly less lactose per serving than the regular version of the food…perhaps only 1 or 2 grams per serving.
  • “Reduced” Lactose means the food contains 25% less lactose per suggested serving size than the regular version of the food.

Therefore, when choosing an MPC or MPI to use in a lactose-free, low-lactose, or lactose-reduced food application, one is required to calculate that amount of lactose present per serving in the food application and then calculate how much lactose would be added to the food via addition of an MPC or MPI to the food product. We would suggest that a low-lactose MPC or low-lactose MPI would be best to use in such applications.

Note: The information provided here is thought to be accurate but because of the sensitive nature of label claims, we recommend that you seek legal counsel before making any claims on food product labels. FDA regulations are very specific for food labeling claims and, as such, need to be interpreted by an expert in the regulations for each food application.

Even at refrigerated temperatures, as milk sits around, reactions occur. Calcium and phosphorous will react with each other to form insoluble calcium phosphate salts and they will also react with the casein and whey proteins to decrease protein solubility. Fat in the milk will hydrolyze and oxidize, modifying the flavor characteristics of all of the milk ingredients. While these reactions may not be visible at the time of processing, they will affect shelf life and the functional properties of MPC powder.

At Idaho Milk Products our IdaPro MPC and MPI powders are made from the freshest milk in the world.

To begin the manufacturing process, milk is collected at dairy farms that belong to and are completely under the control of our farmer-partners. These farms are all within a 45 minute transport drive from our processing facility. The milk is immediately cooled to refrigeration temperatures at the dairy farms and stored under refrigeration until it is soon collected for transport to the facility. From the milking parlor forward, the milk is maintained in a hygienic, closed loop system (i.e., is not exposed to air) until the finished product is packaged at the facility.

Under our normal operating procedures, less than 24 hours will elapse between milking of the cows and final packaging of the finished MPC/MPI/MPP powders. In other factories around the world, the milk used is at least 24 hours old before the factories begin the manufacturing process. That is why independent lab testing has shown that IdaPro MPC/MPI powders have superior solubility and sensory properties compared to the competition.

To understand seasonal variation of cow’s milk, one first needs to understand that all cow’s milk is produced by a cow as part of the mammalian lactation cycle for feeing of infant mammals.

Once a cow begins the pregnancy cycle, the lactation cycle begins. When a calf is birthed (as with all mammal births) the mother cow begins to produce milk. For the first 48 hours, the milk is not what most people would think of as “milk” … it is a somewhat clear liquid that is called colostrum. Colostrum contains mostly whey protein fractions to support the baby’s immune system such as lactoferrin, immunoglobulins, and even growth factors (because most mammals are born with a low functioning immune and hormonal system). The colostrum gives mammal newborns a “jumpstart”. Over the first 48 hours, the mother’s milk changes rapidly in composition. The casein levels increase and whey protein levels decrease. After 48 to 72 hours, cow’s milk becomes much closer to the appearance and definition of what we consumers think of as cow’s milk. What people don’t realize, however, is that cow’s milk continues to change in composition throughout the entire lactation cycle of the mother cow. Because the composition of milk does not remain constant throughout the milking season, manufacturers who use milk proteins as ingredients in their applications notice these changes. It is these changes in the milk composition that can cause numerous formulation headaches for end users. See the graph below for a general overview of the changes in milk production through a season.

Within the first 4 to 8 weeks of a cow’s lactation cycle, the volume of milk builds up rapidly, leading to a peak volume. Then, after approximately 10 weeks, the milk volume per cow starts to decrease. Throughout the remainder of the season, milk volume continues to decrease. At the beginning of the season, during the build up and peak volumes, the milk is higher than normal in whey protein content. Higher whey protein levels can cause discoloration of the MPC
powder, decreases in MPC viscosity, decreases in MPC heat stability, gellation during heat processing or lower solubility after heat processing, and poor quality cheese curd or yogurt gels manufactured from the MPC. In the middle of the milking season, the composition is much as would be expected from textbook descriptions of milk. As the season winds down however, the whey protein content continues to decrease and the casein portion increases. At the same time the mineral content of the milk begins to increase, especially those minerals that are known to “interfere” with the desirable functional properties of milk proteins. As the milk minerals increase, MPC functional properties will again change. Viscosities will modify (either higher or lower depending on your formula), the mouth feel of the MPC will become less smooth (more grainy), the MPC will exhibit decreased solution stability in the presence of added minerals, stability after high heat pasteurization could become more pronounced, and MPC used in cheese or yogurt will again exhibit different curding characteristics. Anyone who has ever made Ready to Drink UHT milk based beverages knows that such changes in milk composition pose tremendous challenges for production crews – higher than expected whey protein contents can lead to heat gellation and/or lower solubility of the protein, while higher than expected mineral levels can result in diminished solubility/suspendability of the protein.


Yes, through proper herd management. It is possible to maintain a consistent balance in a dairy herd of the numbers of cows at all stages of the lactation cycle by practicing what is known as “herd rotation” – at any time during the 12 month calendar year, the same number of cows are at all stages of lactation, resulting in a consistent composition of milk coming from that herd.

The farmer/partners of Idaho Milk Products are not seasonal dairy farmers. The dairies that supply our milk “rotate” their herds so that roughly the same number of cows are calving and lactating throughout the year and milk production remains relatively constant. The resultant milk used in our factory therefore remains relatively constant in composition. The advantage for you, the end user, is that you will receive an IdaPro MPC/MPI with the same functional properties in January, June and November. Your production will proceed with fewer problems and your product quality will be consistent at the levels you desire throughout the year.

True rotation of herds is only possible, however, when the cows are fed the same feed supply throughout the year. Of all of the dairy regions of the world, the only region that practices wide scale formula feeding of the dairy herds is the Western USA. Throughout the North Central and Eastern USA as well as in Europe and in Oceania, cows are pasture grazed. The pastures are not always ideal for grazing during certain times of the year. This is when farmers in these regions usually let their cows “dry up”. Have you heard other milk protein vendors talk about the “new season” or “next season”? They are actually talking about the seasonality of their milk supply. In every country other than the US, manufacture of milk proteins has a definite season. In Europe the season begins in March and extends to November. In Oceania, the season begins in October and extends to April/ May, depending on how fast the cows start drying up. Throughout the 8 or so months that these regions milk their cows for the manufacture of proteins, the composition of their milk changes. As we have seen above, changes in milk composition result in production problems for manufacturers.

Yes, feed composition is a large determinant factor of cow’s milk quality/ consistency. Have you heard the old saying … “You are what you eat”? Well, this saying holds especially true for cows.

The quality of milk produced by a cow is determined by what the cow eats. A cow produces milk from the components of the food that it consumes. In most parts of North America, in Europe, and in Oceania, cows are pasture fed. Throughout the year, with varying intensities of sunlight and temperature, pasture grasses change in composition. In spring, the grasses are a dark green, filled with chlorophyll and carotene. In fall, field grasses start to dry up. The nutrients in those grasses changes constantly throughout the milking cycle. If the feed composition is constantly changing, the resultant milk composition also changes. The diet of pasture fed cows is strictly up to the whims of nature.

The herds of the farmer/partners of Idaho Milk Products do not feed on field grasses. They are fed a scientifically formulated diet consisting of a mix of grains, corn, and grasses. Staff veterinarians carefully plan the diets. Dietary composition is carefully monitored to ensure the same levels of required nutrients every day of the year. The result is milk that is compositionally the same throughout the year. IdaPro MPC/MPI manufactured from this milk can be expected to be consistent in quality all year.

Yes, depending on the amount of heat exposure, heat can cause properties of an MPC to change. That does not mean that heat will always cause changes in MPC properties. At standard food processing temperatures and hold times (example: 162°F for pasteurizing), MPC will undergo negligible to slightly perceptible changes. At higher temperatures above 180°F (82°C), however, changes to MPC properties will be more noticeable.

There are two ways in which heat can affect MPC:

  1. Denaturation of the whey proteins present in the MPC
  2. Accelerating calcium-casein reactions

Excess heat exposure can cause:

  1. Decrease of protein solubility
  2. Decrease in emulsion stabilizing
  3. Change in organoleptic properties in food and beverage applications—texture and flavor
  4. Increase in aqueous viscosity

Typically, standard food processing temperatures and hold times, such as standard dairy pasteurization temperatures, will result in a small amount of whey protein denaturation. Such a small degree of whey protein denaturation would have a negligible to slightly perceptible effect on MPC properties. A slight drop in protein solubility and whey protein solubility might occur. It is highly doubtful that even a trained technician could detect significant differences in MPC properties if the MPC is only subjected to usual food processing conditions of less than 165°F (74°C) for seconds.

At higher processing temperatures, increasing percentages of the whey proteins in MPC will heat denature. As the whey proteins heat denature, they become less soluble, even precipitating out under certain circumstances. The loss of increasing whey protein solubility can affect emulsion stabilization and organoleptic properties of the MPC. If the whey proteins become so insoluble that they precipitate out of solution, food texture can be adversely affected. Extreme denaturation of whey proteins is almost always accompanied by a release of sulfur. Flavor and aroma characteristics of food products can be adversely affected as the sulfur is released.

If, on the other hand, a protein application calls for ultra-high heat (ultra-high temperature) exposure, then significant changes will occur with dairy proteins. At typical UHT conditions, the whey proteins in the MPC will be mostly heat denatured. Due to the processing conditions, however, they do not adversely affect texture and have only a slightly perceptible effect on flavor and aroma. While many experts will advise that casein does not denature at temperatures below 400°F, casein micelles will undergo some changes at UHT processing conditions. As an example, in UHT processed ready-to-drink (RTD) beverages dairy proteins are usually processed at temperatures well above 290°F (143°C) and are held at such temperatures for a few seconds to sterilize the beverage. Immediately after UHT processing, it appears that no changes occurred in the MPC (except for the obvious denaturation of almost all of the whey proteins). After several days, however, changes begin to occur in the beverage. The viscosity increases and eventually, the beverage turns into a gel or a precipitate forms. While the heat exposure did not cause a disruption of the casein micelle structures in the MPC, the heat exposure did change the “character” of the casein micelles. In simplistic terms, typical casein micelles in milk will contain about 90% of the total milk calcium. Much of the calcium present in the micelle is bound calcium. A portion of the micelle calcium, however, is not bound (free calcium) but is instead “trapped” inside the structure of the micelle. As heat is added to the system (heat = energy), the chemical bonds of the micelle “stretch” and the micelle expands in size. As the micelle expands in size, the free calcium inside the micelle is liberated to migrate to the outer surface of the micelle. Once at the outer surface, the calcium helps to change the ionic character of the micelle surface. Micelles start reacting with other micelles, agglomerating until their aggregated size is so large that they become less soluble or form a gel matrix. For this reason, UHT processed RTD beverages almost always contain a small amount of complex phosphate salts to prevent the micelles from agglomerating after UHT treatment.

The U.S. Government requires that all milk used for further processing be pasteurized (unless one has a raw milk license). Therefore, prior to processing the skim milk into MPI/MPS, we pasteurize the milk using high-temperature short-time (HTST) conditions (72°C for 22 seconds). Everyone around the world does this. The skim milk is immediately cooled back down to less than 10°C and held there until we begin filtration. We use cold filtration techniques. There is a little bit of heat buildup during the filtration process, but our temperatures do not exceed 15 to 20 °C. We really like to differentiate ourselves from the rest of the MPI/MPS suppliers because we do not use a heat step to increase the solids of our protein prior to spray drying. Everyone else will use some sort of evaporation step to concentrate the solids in their protein dispersion prior to spray drying. That evaporation step requires added heat. We do not use evaporation or any added heat to concentrate our solids prior to spray drying. Many will tell you that the evaporation step isn't that critical to protein function, but it is...because the protein is in a concentrated form at this point and the added heat has an enhanced deleterious effect on the protein's ability to form films, etc. Therefore, we feel very confident in bragging that we use a low heat process because we do not expose the protein to added heat of evaporation prior to spray drying. Our competitors cannot say that.

YES. Different MPC manufacturers follow their own, unique processing methods. Just as milk powders can vary in heat exposure and heat damage from one manufacturer to another, MPCs can vary from one manufacturer to another. Milk powders are graded according to their heat exposure/damage by assaying the powders for undenatured whey protein nitrogen. The powders are usually classified into low heat (treatment), medium heat (treatment), or high heat (treatment) classifications. A low heat powder would have the least damage from heat while a high heat powder would contain very little, or no undenatured whey protein. The same testing methods can be used to compare heat exposure/damage of MPC powders. The Hungarian Dairy Research Institute, pioneers of MPC manufacture, compared Idaho Milk Products’ MPC 80 to competitive brands from around the world. They used the American Dairy Products Institute (ADPI) Method for Determination of Undenatured Whey Protein Nitrogen in Nonfat Dry Milk (modified to reflect the higher protein content of MPC) to compare heat exposure of the varying MPC powders. By the ADPI testing method, a low heat milk powder is considered to contain a minimum of 6.0 mg undenatured whey protein nitrogen per gram of powder. A medium heat milk powder will contain from 1.51 to 5.99 mg undenatured whey protein nitrogen per gram of powder and a high heat milk powder contains 1.50 mg undenatured whey protein nitrogen or less per gram of milk powder. The results showed that Idaho Milk Products’ MPC had been exposed to significantly less heat than the competitive powders, yielding undenatured whey protein nitrogen values (15 mg per gram of powder) that were almost double that of the next nearest competitor (8 mg per gram of powder). Idaho Milk Products’ MPC had two and a half times the undenatured whey protein of the average competitor MPC (6 mg per gram of powder). At least half of the MPC powders tested by the Hungarian Dairy Research Institute assayed as medium heat powders.

The Maillard Reaction, or sometimes it is more commonly known as the Maillard Browning Reaction, is a chemical reaction between an amino acid (or a protein) and a reducing sugar. The two chemicals form a new compound that is significantly altered from a simple amino acid and a simple sugar. The new compound may exhibit lower water solubility than either of the two chemicals separately. The new compound may impart a new flavor. Although the Maillard Reaction has been a practical part of cooking food since prehistoric times, it was only scientifically observed and studied about 100 years ago. Most people with knowledge of the Maillard Reaction in food products think that heat (of the extreme such as is used in cooking) is necessary in order for the reaction to proceed. In actual fact, however, the reaction has been proven to proceed even while food products are stored at refrigerated temperatures over prolonged storage times. Again, most people with knowledge of the reaction would say that “browning” of food products is a part of the reaction. In actual fact, the Maillard reaction will occur in food products many times without any occurrence of ”browning.” The “browning” stage of the reaction can occur at the end stages, after sufficient water has disappeared from the food product. As the Maillard Reaction occurs in food products, new flavors are produced. Depending on the type of reducing sugar involved and the amino acid with which the sugar reacts, hundreds of different flavors result from a Maillard Reaction. The resultant Maillard flavors can be beneficial or bad for a food product. Some of the more common food items that are dependent on the Maillard Reaction for beneficial flavor development:

  • Toasted Bread
  • Many Bakery Products
  • Malted Grains (Beer, Whiskey)
  • Meats cooked at high temperature (BBQ, Broil)
  • Condensed Milk
  • Aged Dried Milk (staling)
  • Dulce de leche
  • Crème brûlée

Since MPC contains both protein and a reducing sugar, lactose, one can expect Maillard Reactions to occur when MPC is used in food applications. In many cases, the reaction will be desirable. In some cases, however, the reaction will produce undesirable results. In those instances, precautions must be taken to prevent the reaction from occurring.

Maillard browning is a chemical reaction that usually occurs between amino acids (the building blocks of protein) and those carbohydrates known as reducing sugars – although the reaction has been known to occur between reducing sugars and whole proteins. In a Maillard reaction, the reactive carbonyl group of a reducing sugar molecule reacts with the nucleophilic group of an amino acid, causing a change in color (usually darkening of color) and flavor of a food product. Heat (energy) is usually required for a Maillard reaction to proceed. Reactions between reducing sugars and free amino acids occur easily and with very little heat required. Reducing sugars will also easily react with the reactive terminal end amino acids of hydrolyzed proteins and, again, very little heat is required.

Reactions between reducing sugars and amino acids that are part of a whole protein are less common and require more heat (energy) to proceed. In the food industry, the troublesome Maillard reactions that occur over shelf life time are usually those reactions between reducing sugars and free amino acids or small peptides (fragments of proteins) that result from protein hydrolysis that occurred during food processing. The visible result of a Maillard reaction is development of a darker color … called browning. A flavor change usually accompanies the development of the darker color.

Usually, when one talks about protein function, it is in reference to the metabolic fate of the protein once in the bloodstream and/or the protein's functional properties as a food ingredient/stabilizer. So, when we say that the protein remains highly functional, we are referring to the protein's ability to affect metabolic pathways in the body (as desired) as well as the protein's ability to perform functions in food applications...emulsification, foaming, and, in the case of cheese making, forming a desired curd texture. Of course, all of these functional properties are compared to the functionality of the proteins as they are naturally found in milk. What we are really saying is that our processing of the MPI/MPS does not adversely affect the proteins and they retain their natural functional properties as when they are found in milk.

Milk Protein Concentrate (MPC) and Milk Protein Isolate (MPI) is usually sold as a fine, white powder. In water, MPC/MPI forms a white, opaque dispersion of low viscosity – looking very similar to milk. MPC/MPI will remain suspended for prolonged periods of time in water. A well manufactured MPC/MPI will have no odor and a bland flavor profile. In water, a 10% dispersion of MPC/MPI has a smooth, creamy mouthfeel.

Solubility of dairy proteins is measured by determining the quantity of protein nitrogen that is water soluble versus the quantity of protein nitrogen that is water insoluble. Proteins are long chains of amino acids. Nitrogen is part of the backbone of every amino acid. Therefore, to measure protein solubility, one needs only to measure the solubility on the amino acid nitrogen in the protein. There are many slightly different methods for measuring protein solubility. Each one, because of the slightly different analytical procedures, will yield differing results with some yielding higher solubility values and some yielding lower solubility values for the same protein sample.

Therefore, when measuring dairy protein solubility, it is important to analyze all protein powders using the same analytical methodology in order to yield results that show relative solubility values. While there are many methods, most of them involve the following steps:

Protein Solubility (Nitrogen Solubility Index)

  1. Mixing a known quantity of protein powder into water.
  2. While keeping the dispersion temperature below that which would cause protein denaturation (usually below 130°F and usually around room temperature), allow the protein to hydrate for a specified amount of time.
  3. A sample of the aqueous protein dispersion is removed and analyzed for total protein content (total nitrogen content).
  4. Another portion of the same protein dispersion is centrifuged for a specified period of time at a specified centrifugal force. Centrifuging should yield a precipitate at the bottom of the centrifuge tube and a clear supernatant.
  5. Just to be sure, the supernatant is usually filtered through fine filter paper to remove any insoluble protein fines that may still be floating in the supernatant.
  6. The centrifuged and filtered supernatant is then analyzed for protein content (nitrogen content). The supernatant contains the water soluble protein.
  7. NSI is calculated by dividing the supernatant protein content by the total protein content and multiplying by 100.

Whey Protein Solubility (Whey Protein Nitrogen Index)

The steps are pretty much the same as for NSI, with the exception that one must first remove all casein nitrogen from the milk or MPC sample without causing damage to the whey proteins. This is usually accomplished by addition of certain chemical agents that will cause a complete precipitation of the casein as a curd but will not cause damage to the whey proteins in between steps 3 and 4 above (after a sample of the hydrated protein dispersion is removed for total protein nitrogen analysis). Once the casein curd has been precipitated out, it is filtered away from the resultant whey and the whey is subjected to the same procedure as for NSI determination. The whey contains the soluble portion of the whey protein. That portion of the whey that was denatured and insoluble is removed with the casein precipitate. WPNI is calculated by dividing the protein content of the clarified whey by the total protein content (before the casein and insoluble whey protein were removed) and multiplying by 100.

Of course, there are more recently developed methods involving the use of chromatographs to determine both casein content and whey content of samples. Most companies, however, rely on the centrifugation method to determine dairy protein solubility.

These two terms are usually used in conjunction with discussions of protein solubility. NSI stands for Nitrogen Solubility Index and is expressed as a percentage of the protein nitrogen that is water soluble relative to the total protein nitrogen present. For example, if 75% of the total nitrogen contained in a protein is found by analysis to be water soluble, then the NSI is said to be 75. NSI is used to demonstrate total protein solubility. NSI values for MPC powders can be affected by:

  1. Age of the milk when the MPC was manufactured
  2. Manufacturing conditions
  3. Exposure to heat
  4. The presence of reactive minerals.

Fresh milk (0 to 24 hours old) will yield a more soluble MPC than will older milk. As milk sits in a silo, even at refrigerated temperatures, there are reactions that occur within the milk. Most of these reactions result in a decrease of milk protein solubility. A general rule of thumb is, fresher milk makes more soluble MPC. Manufacturing an MPC can be very tricky to those who don’t know what they are doing. There are subtle changes to MPC protein that will occur if the protein becomes too concentrated at the wrong time. Basic chemistry states that the more one concentrates molecules in a confined space, the faster they will react with each other. Many of these accelerated reactions prove detrimental to MPC solubility. As we have already covered, increased heat exposure during manufacture of MPC will result in a loss of solubility due to whey protein denaturation and calcium-casein interactions. MPC solubility can also be affected by the presence of reactive, free minerals. Calcium and magnesium ions will readily react with casein and cause the casein to lose solubility. Care needs to be taken during MPC manufacture to avoid liberating ionic calcium and magnesium.

WPNI, otherwise known as Whey Protein Nitrogen Index, is a measurement of whey protein solubility. As with NSI, WPNI is expressed as the amount of whey protein nitrogen that is water soluble relative to the total amount of protein nitrogen present. WPNI is usually used as a measuring stick to determine the amount of heat exposure a dairy powder has undergone. With higher heat exposure during manufacture, whey proteins will denature and become less water soluble, resulting in a powder with low WPNI value. A high WPNI value signifies less heat exposure and less whey protein denaturation. A low WPNI value signifies excessive heat exposure and a high degree of whey protein denaturation. For example, in nonfat dry milk (NFDM) with a total protein content of 35%, a low heat treated NFDM might have a WPNI result of 6.0 (6.0% of the whey protein nitrogen is water soluble versus the 35% total protein nitrogen). A high heat treated NFDM might yield a WPNI result of 1.2, signifying that most of the whey proteins in the skim milk have been heat denatured during the heating process. For an 80% protein MPC powder, the WPNI value should be much higher. In theory, an 80% protein MPC powder could contain as much as 18% whey protein nitrogen (soluble and insoluble). Therefore, a low heat exposure result for an MPC 80 powder would be somewhere in the range of 14 and higher while lower WPNI values would reflect increasing levels of heat exposure.

In analyses by outside laboratories, NSI results for MPC powders were found to range from a low of 35 to a high of 72.

NSI results for three separate lots of Idaho Milk Products’ IdaPro® MPC powders ranged from 67 to 72. An outside laboratory also analyzed MPC powders for WPNI. Typically, most MPC powders have WPNI values of 4 to 7. Idaho Milk Products’ IdaPro® MPC 80 was found to have a WPNI value above 15.

The results of both analyses indicate that IdaPro® MPC 80 is more carefully manufactured than other MPC powders and was likely exposed to less overall heat load during manufacture, thereby suffering significantly less protein denaturation and functional property changes from heat during processing than other brands of MPC powders.

Solubility of MPC/MPI is an important quality characteristic that determines how successful the product will be in various applications.  This important product attribute can be affected by several process parameters including freshness of the raw milk prior to processing, processing conditions, and length/conditions of storage.

In order to maximize MPC solubility it’s important to minimize the potential for casein micelles to react with each other and agglomerate into larger micellar structures.  These agglomerations are what lead to solubility issues.  Like most chemical reactions, the more time, energy, and concentration put into the MPC production process the more likely casein micelles are to form large insoluble agglomerates.  For this reason, IMP ensures that our milk is processed from raw milk to a powder within 24 hours of milking the cows at the farm. To further inhibit micellar agglomeration, IMP employs “cold process filtration” in the manufacture of our MPC and MPI. It is void of any heat input after pasteurization. We do not use a high heat evaporation step to concentrate the MPC prior to drying, as is utilized by most ultra filtration factories around the world.  In addition, we try to manufacture our MPC/MPI on a just-in-time basis, to fit pending orders, so that the amount of time it sits in our warehouse prior to shipping to the customer is greatly reduced.  With these strategies in place, IMP provides customers with MPC/MPI that is second to none with regards to solubility.

The response to this question is dependent upon the context in which you are asking the question. In a laboratory situation, suspension stability is measured by dispersing a protein powder in ambient temperature water (10% w/w) and pouring the aqueous protein dispersion into a 100 ml graduated cylinder. One then observes how long it takes the first sediment to appear at the bottom of the cylinder as well as the total sediment volume over a specific time period (say, 4 hours). The protein that will remain in suspension the longest displays superior suspension stability and also the protein that settles out the least over a specific time period also displays superior suspension stability.

In real-life applications, however, suspension stability is much more commonly referred to as how well the protein powder remains suspended in water or other liquid after it has been thoroughly dispersed in the liquid. For example, in high protein ready-to-drink shakes, suspension stability is determined by how long the protein will remain suspended in the drink over the shelf life of the product. In cheese making, suspension stability would have more to do with how much settling out the protein powder evidences after being dispersed in milk.

Basically, when we talk about suspension stability, we talk about how well the protein stays suspended in cold to ambient temperature liquids prior to, or in the absence of, added heat. Once heat is applied to the dispersion, then suspension stability and solubility become one and the same.

The number one key factor is compatibility of the protein with the other ingredients in the system. For instance, excess free calcium is well known to cause a decrease in milk protein suspension stability and solubility. Sodium phosphate salts are well known to increase milk protein suspension stability and solubility. Probably the second most important factor would be how the powder was dried. With milk protein powders, spray drying conditions can affect how fast water can penetrate the outer layer of the powder particle. If the powder particle is too resistant to water permeation, then the powder is more likely to display poor suspension stability. Third factor would be the temperature of the protein dispersion. Obviously, the higher the temperature when the protein is dispersed into water (within reason...temperatures in excess of 50°C should be avoided), the better the suspension stability.

Very little actually. But there are some differences. It is possible to have a protein powder that is highly soluble but displays poor suspension stability. Conversely, it is also possible to encounter a protein powder with good suspension stability and relatively low solubility. Suspension stability, as discussed above, is really a measure of how well the powder stays suspended in water after it is dispersed into ambient temperature water. All other things being equal, this is really a matter of how impervious the outer layer of the powder particle is to water penetration. A water-impervious outer layer will make a powder display poor suspension stability (because it is taking the water too long to penetrate into the inner layers of the particle and make the particle truly soluble). Solubility of a protein is usually measured by dispersing a protein powder in ambient temperature water, followed by heating the protein dispersion to at least50°C (and usually 70°C) and holding the protein dispersion at that temperature for a specified period of time to allow for maximum hydration/solubilizing of the powder (the dispersion is then cooled to room temperature and centrifuged to determine the percentage of soluble versus insoluble material present). The elevated temperature hold allows water to penetrate even the most impervious of particle outer layers, thereby allowing the water to penetrate the particles maximally. Water penetrated particles will have reached their maximum solubility level. So you see...a powder that might display lower suspension stability (due to a more impervious outer layer) could actually display high solubility (once the water has thoroughly penetrated into the particles).

Yes. All high protein powders experience degrading chemical reactions as they age. When MPC/MPI powder ages, reactions such as residual fat hydrolysis, loss of solubility, and Maillard browning will continually progress. These chemical reactions are fueled by the concentration of the milk proteins in close proximity with milk minerals and remaining sugar as well as residual lipolytic and proteolytic activity. Such reactions have a negative effect on protein powder properties. For example, the Maillard Reaction, or sometimes it is more commonly known as the Maillard Browning Reaction, is a chemical reaction between an amino acid (or hydrolyzed protein peptides) and a reducing sugar (in the case of milk, lactose). The two molecules form a new compound that is significantly altered from a simple amino acid and a simple sugar. The new compound may exhibit lower water solubility than either of the two chemicals separately. The new compound may also impart a new flavor and in many cases, the new flavor can be overpowering.There are also numerous studies that show that MPC/MPI powders lose solubility in storage. The leading theory is that calcium and phosphorous in the MPC/MPI powder will react with the proteins and cause a loss of protein solubility. In addition, dairy powders contain residual levels of native milk enzymes. These enzymes will, over time, hydrolyze fat and protein in powders and can cause formation of bitter fatty acids and/or bitter protein peptides. The newly formed fatty acids and peptides will detract from the fresh, bland flavor of the powder and could even affect overall protein solubility.

It is important to utilize the freshest MPC/MPI powders available to ensure that your products will have maximum shelf life. Most MPC powders sold in the USA are manufactured overseas. By the time these powders clear US ports, they are months old. Idaho Milk Products manufactures IdaPro® MPC/MPI powders domestically and on a make-to-order basis. IdaPro® MPC/MPI powders can be delivered anywhere within North America within weeks of manufacture, thus ensuring that your food products will exhibit the best sensory, solubility, and maximum shelf life properties. These properties are very important in ingredient sensitive applications such as Ready-to-Drink protein beverages. In such applications, the solubility of the protein will affect shelf stability (beverage gelling or clotting) and the MPC/MPI flavor will affect how much flavor and what type of flavor needs to be added to manufacture a pleasant tasting consumer product. Fresh MPC/MPI powders are essential ingredients for manufacturing the best Ready-to-Drink clinical, adult, and sports nutrition protein beverages. IdaPro® MPC/MPI powders are the freshest available in North America.

In many cases, yes. You will probably find that IdaPro MPC/MPI delivers a better flavor and more soluble mouthfeel than other MPC/MPI powders. For example,  manufacturers of high protein Ready to Drink products have found that they can decrease added flavoring levels and decrease stabilizing salt levels when they use IdaPro MPC/MPI powders compared to other MPC/MPI sources.

They still maintain excellent product flavor and prolonged shelf life stability while decreasing ingredient costs. Just as with RTD products, in many other  applications IdaPro MPC/MPI powders will significantly improve sensory properties while decreasing cost.

Since MPC and MPI are made up of Casein and Whey Proteins, we can look at the glutamine content of each protein to get an idea of the glutamine content of the respective product. Whey protein is reputed to contain roughly 7% to 8% glutamine (per 100 grams of amino acids). Casein has a slightly higher glutamine content that usually ranges from 8% to 10% (per 100 grams of amino acids). MPC and MPI will usually contain 7% to 9% glutamine, based on the total amino acids present. That means that our MPC-80 powder will have an “as is” glutamine content of roughly 6.5% to 7.5% and our MPI-85 powder will have an “as is” glutamine content of 7% to 8%.

First, it is necessary to understand that high heat NFDM is only required for use in some baking applications…not all baking applications. In certain baking applications, high heat treated milk powder is required because whey proteins, in low heat treated powders, that denature during the baking process will interfere with desired final properties of the baked goods. This is not the case, however, for all baked goods…only some baked goods. In many baking applications, medium heat and low heat milk powders can be used as the milk powder ingredient. It is in those applications where our MPC powder can be used as a substitute ingredient for skim milk powder. Also, MPC may be used as a substitute for high heat skim milk powder in some baking applications.

Yes.  Cold filtration manufacture of IdaPro MPI-85% results in a product with approximately 3.6% lactose. To deliver a product with less than 1% lactose, we utilize a very small amount of lactase enzyme which reduces the disaccharide lactose to its component sugars of glucose and galactose, resulting in a product with a typical analysis of 0.85% lactose, 1.4% glucose and 1.4% galactose.

Idaho Milk Products finished MPC is tested on the following schedule for the following items:

Test Item Frequency
Pesticide and Herbicide Residue semi-annual
Heavy Metals semi-annual
Dioxins semi-annual
Radioactivity semi-annual
Melamine and Cyanuric Acid semi-annual


By the method used to run an amino acid assay, the amide group on glutamine is sheared off during the breaking of peptide bonds, changing the glutamine into glutamic acid. They are not the same thing...but by an amino acid assay, glutamine always shows up as glutamic acid. Unfortunately, it doesn't help that the body cannot convert glutamic acid back to glutamine.

The amount of rennet casein that can be replaced with MPC/MPI depends on the type of processed cheese application and the expertise of the manufacturer. In general, almost every manufacturer should be able to replace one-third of their rennet casein requirement with MPC/MPI without any noticeable changes in product quality.

If one replaces too much rennet casein, the most noticeable effect would be a softening of product texture or a significant change in melt rate and spread of the cheese product. MPI-85 would be the most logical product to use when replacing rennet casein. The protein content of MPI-85 is almost identical to the protein content of rennet casein and, therefore, would be a direct substitute for rennet casein without the need of adjusting the formula to meet required protein/fat ratios.

IdaPro MPC/MPI is best used in processed cheese or analog cheese applications to replace caseinates. As stated in the answer to the question above, MPC/MPI can only be used to replace a percentage of rennet casein in those applications before changes in product texture or melt properties become significant. In those non-specific processed cheeses and cheese analog products that use caseinate, however, MPC/MPI can completely replace the caseinate as the protein base of the product without loss of product properties.

People add Milk Protein Concentrate (MPC) and/or Whey Protein Concentrate (WPC) to yogurt as functional ingredients. They are sometimes erroneously referred to as "stabilizers". Prior to MPC being plentiful, it was noted that adding a protein product to yogurt milk did improve yogurt gel stability (shelf life). The higher the viscosity of the protein in water, the better it is at stabilizing...because high viscosity proteins will bind more water. That is why sodium caseinate works the best as a yogurt stabilizer. Sodium caseinate binds much water, thereby extending yogurt gel stability before syneresis and loss of gel structure. This may not seem like a big deal, but it is. Yogurt manufacturers strive continually to extend shelf life. In their efforts to gain longer shelf life, formulators add gums, gelatins, pectins, and starches (all known as stabilizers) to bind water. Regulations in different countries limit how much of these stabilizers a yogurt manufacturer can add. Stirred curd yogurt manufacturers need more stabilizing/viscosity building in their yogurts than the legal maximum levels of stabilizers will sometimes provide. That is when yogurt manufacturers look to milk proteins to perform a stabilizer type of function in yogurt. Initially, yogurt manufacturers turned to WPC for extra stability. With the advent of MPC manufacture, MPC became a preferred functional ingredient in yogurt.

Prior to the introduction of MPC, WPC was commonly used throughout the yogurt industry as the functional protein ingredient to increase yogurt gel strength and decrease gel syneresis (wheying off). A number of dairy industry studies throughout the years have found an increase in yogurt gel strength and a decrease in syneresis in WPC-fortified yogurts as compared to yogurts manufactured from 100% milk. This result isn’t all that surprising because as WPC is added to yogurt milk, the total solids of the milk, as well as the protein content of the milk, is increased. As yogurt total solids and protein content increase, increased gel strength and decreased syneresis result. WPC is from a dairy origin and, therefore, thought to be an ingredient with better consumer appeal, compared to other commonly used stabilizers—“modified foodstarch,” “pectins,” and/or “gelatins.” As a result, many yogurt manufacturers have added WPC to their yogurt as a stabilizing ingredient. As WPC usage in yogurt increased, however, it became apparent that there were limitations as to how much WPC could be added to yogurt formulations before significant sensory defects were encountered. Addition of WPC to yogurt milk results in a yellowish color which intensifies with increasing WPC levels. Excess levels of WPC in yogurt can cause the otherwise smooth yogurt gel to turn grainy, thereby lowering consumer acceptance. Excess levels of WPC were also found to adversely affect yogurt aroma and flavor, resulting in a sensory profile that is not considered normal for yogurt and can cause consumer rejection.

To overcome the issues encountered with use of WPC in yogurt, researchers began using MPC to blend with WPC or totally replace WPC in yogurt applications. Use of MPC results in a more realistic gel texture compared to WPC. Use of MPC in yogurt does not negatively impact the flavor or aroma of yogurt as does WPC. On the other hand, recent studies have demonstrated that yogurt containing WPC may display increased gel strength compared to yogurts containing MPC. Therefore, researchers feel that a blend of MPC and WPC (predominately MPC) may work best in yogurt applications. Use of a blend in which the MPC content is about 80% of the blend (compared to 20% WPC) will yield a yogurt with increased gel strength and decreased syneresis while maintaining desirable sensory properties.

No. Anyone who has seen 10% solids WPC dispersions knows that they're water thin. So, yogurt manufacturers heat denature the added whey protein along with the whey proteins that are present in the yogurt milk. Heat denatured whey proteins bind significantly more water than do undenatured whey proteins. Heat denatured whey proteins do not, however, compare to the water binding properties of casein. Thus, yogurt manufacturers tried adding higher quantities of whey proteins.

Yes. There are two primary problems:

  1. When whey proteins heat denature, disulfide cross bridging between molecules occurs and, with extreme heat, a release of sulfur also occurs. The yogurt pasteurizing step of 195° F for 8 to 10 minutes is extreme and can promote a release of sulfur. The released sulfur has been shown to interfere with a realistic yogurt aroma.
  2. In excess usage levels, whey proteins change the texture of the yogurt gel...making it more like a custard or a pudding rather than the delicate gel structure (like flan) that yogurt lovers expect. The same holds true for other stabilizers (gums, gelatins, starches, pectins).

Whey proteins do, however, impart a nice, smooth mouthfeel to yogurt and so, have found high usage in yogurt.

Yes. MPC is an excellent functional yogurt ingredient. MPC, having the same protein ratios as the milk from which yogurt is made, will not change the expected yogurt gel texture. It imparts the standard casein polymer gel that natural yogurt displays and not the starchy, gummy, custardy, pudding gel that many over-stabilized yogurts today exhibit. Plus, the casein in the MPC binds significantly more water than does WPC. A yogurt manufacturer can use less MPC to gain more gel stability and longer shelf life than they can with WPC. As an added value, yogurt manufacturers do not encounter the annoying sulfur aromas and changes in gel texture that accompany use of WPC at higher levels.

MPC is a valuable functional ingredient in Greek-style yogurt. The lowest protein content of the Greek yogurts for sale in the USA are 2 times regular yogurt protein content. If we look at regular yogurt as 3.2% protein, then Greek- style yogurts would have protein contents of 6.4% and up. If one wants to manufacture Greek-style yogurt without also manufacturing the undesirable and hard-to-dispose-of acid whey, then the only solution available is to fortify the Greek-style yogurt milk to a desired protein content prior to culturing/fermentation. MPC can be used to fortify Greek-style yogurt milk with added solids and protein. Once the Greek-style yogurt milk is at desired protein content, a manufacturer is able to make Greek-style yogurt without generating acid whey that is fast becoming a disposal problem.

Yes. When MPC is utilized at higher levels in yogurt formulas, the casein starts to impart a gritty, grainy texture to the yogurt gel. This is not a significant problem with regular yogurts here in the USA or in Europe, as it is highly unlikely that a manufacturer would add MPC to their yogurt milk in high enough levels to impact the smoothness of the yogurt gel. It becomes a problem for yogurt manufacturers in those countries that have limited milk supplies and need to use higher quantities of MPC to extend out their milk solids for yogurt manufacture. Milk is in short supply in regions such as Asia, the Middle East, Northern Africa, tropical locales like the Philippines, parts of South America, and even Canada to some extent. In countries with limited milk supplies, where manufacturers would use MPC as if it was fluid milk by diluting MPC dispersions back to fluid milk composition, yogurt gel textures could start to become grainy as the usage level of MPC increases in the yogurt milk. Even so, many of these countries do not experience any major problems with gel texture in regular yogurts. For those that do experience problems, blends are available that include both MPC and WPC. The MPC provides gel strength/stability and a realistic gel texture. WPC tends to help smooth out the yogurt gel. Such blends of MPC and WPC would allow a yogurt manufacturer in milk-deprived regions to advance from replacing 20% of skim milk solids with MPC or WPC to perhaps, 50% replacement of skim solids with a MPC/WPC blend without a significant loss in product quality.

Yes. Some practical yogurt industry work has shown that, in combination with proper stabilizers, MPC can be used to fortify 3.2% protein milk up to about 6.4% protein yogurt milk without a corresponding loss of gel smoothness. At fortification levels above 6.4%, resultant yogurt gels start to become grainy in texture, losing the smooth mouthfeel that is desired by consumers.

If a manufacturer wants to make a Greek-style yogurt with a protein content above 6.4%, we suggest using WPC in combination with MPC to obtain the remainder of desired protein fortification above 6.4%. As with regular yogurt, the MPC will provide realistic yogurt gel texture and bind water for prolonged shelf life of the yogurt while the WPC will help to maintain the smooth mouthfeel desired by consumers.

It depends entirely on the desired yogurt protein content. We would recommend:

6.4% Protein Greek-style yogurt: 3.2% protein from the yogurt milk, 3.2% protein from MPC or an MPC/WPC blend. 100% MPC or a 90% MPC/10% WPC blend.

7.0% Protein Greek-style yogurt: 3.2% protein from the yogurt milk, 3.0% milk protein from MPC, and 0.8% protein from WPC. The MPC/WPC blend would be 79% MPC and 21% WPC.

9.5% Protein Greek-style yogurt: 3.2% protein from the yogurt milk, 3.2% milk protein from MPC, and 3.1% protein from WPC. This blend would be 51% MPC and 49% WPC.

We can definitely say that MPC will contribute to a more realistic milky and yogurt flavor than will WPC. Whey proteins are not primary to yogurt...in authentic, old fashioned 3.2% protein yogurt without stabilizers, the whey proteins are present only at a level of 0.58% while casein is present in the yogurt at a level of 2.62%. To increase whey protein levels above their naturally occurring levels in yogurt, the whey proteins would then start to "add" to the overall flavor of the yogurt, and not in a realistic way. MPC, being concentrated skim milk solids and containing milk proteins in their natural ratios as found in milk, would only "add" milk flavor to yogurt. MPC would impart a more realistic flavor when added to yogurt as a functional ingredient.

Acid whey is a byproduct of making acid types of dairy products including high-protein or Greek-style yogurts made with a centrifuge method. In order to concentrate the yogurt, the whey is “strained” off. While acid whey can be used in limited quantities in many applications including animal feed and fertilizer, the quantity produced by many manufacturers is difficult to manage.

High-protein or Greek-style yogurt made with MPC eliminates acid whey waste by straining skim milk solids before making yogurt and eliminating the need for a second straining step that generates acid whey after the yogurt is manufactured. When used at the optimal levels, the water binding properties and flavor attributes of MPC result in creamy, great tasting yogurt without the need of adding an extra centrifuging step at the conclusion of the yogurt making process.

For purposes of this discussion, ready-to-drink (RTD) beverage will refer to that group of protein-fortified beverages that are shelf stable, i.e., do not require refrigeration for storage and transportation. RTD beverages all have one thing in common no matter how they have been processed. Microbiological assays on RTD beverages yield values of zero or none detected. A properly manufactured RTD will, for all intents and purposes, be commercially sterile until the package is opened. Obviously, the common method used to achieve these minimal microbiological levels is heat treatment. It is safe to say that RTD beverage pasteurization heat treatments surpass the heat thresholds required to denature whey protein fractions, whether the RTD was manufactured via retort or Ultra High Temperature (UHT) pasteurization followed by aseptic packaging. Therefore, whey proteins (WPC and/or WPI) are not the best protein ingredients for RTD beverages because they will denature and lose solubility when exposed to the rigorous heat treatments required to manufacture a shelf-stable RTD. The first wave of high protein RTDs that came on the market were all manufactured using a high level of WPC or WPI because the technology for stabilizing casein micelles against high heat conditions wasn’t as advanced as it is today. Initial trials to manufacture RTDs containing casein ended with the RTDs forming irreversible gels just days after processing. To avoid the casein gelation, early RTD formulators only used WPC or WPI for protein fortification. The intense heat treatment, however, would cause the whey proteins to denature and lose solubility. When whey proteins denature, they form extremely fine flocculants that are not readily observable without sophisticated analysis. It takes days or weeks before one can visibly detect a settling out of denatured whey proteins. Such was the case with WPC RTD beverages…they initially appeared to have survived the heat treatment but days to weeks later, the whey proteins were settling out to the bottom of the RTD packaging or floating to the top of the beverage. Formulators, therefore, had to add stabilizers to maintain the fine particle denatured whey proteins in suspension in the beverage. Even with the addition of stabilizers, RTDs made with whey protein had poor shelf life, with most falling apart in just a few months.

MPC, on the other hand, is heat stable, even at UHT pasteurizing temperatures and one can manufacture RTDs with excellent shelf life using MPC for protein fortification. Since MPC is primarily casein based, it possesses excellent heat stability compared to WPC. The casein in MPC, however, is in micellar structure and exposure to high heat conditions can initiate casein micelle aggregation which, if unchecked, will lead to the irreversible formation of a gel in the RTD. In many cases, these gels appear within days or weeks after processing. Fortunately, there is a known way to retard casein micelle aggregation caused by heat exposure. Addition of a small amount of complex polyphosphate to the RTD will slow down heat stimulated casein micelle aggregation to the point where RTD beverages containing MPC remain stable for as long as one year to 18 months after processing. MPC is now the preferred protein fortification ingredient for RTD beverages.

Milk Permeate contains primarily crystals of α-lactose monohydrate and have a characteristic tomahawk-like shape. These crystals are very hard and brittle. Milk permeate also contains all of the mother liquor which is typically separated out of refined lactose. This mother liquor is made up of denatured casein and smaller whey proteins, vitamins, and minerals. Milk Permeate produced at IMP is primarily comprised of α-lactose Monohydrate. In its crystalline form, each lactose molecule is associated with one molecule of water. The water is incorporated in the crystal and forms an integral part of it. It is not removed by normal drying processes. When working with formulators, it is important to understand the free and bound moisture content of any Lactose crystal as it will lend to degradation by Maillard browning, which in turn shortens shelf life. Free moisture is on the “surface” of the lactose crystal and is measured by drying at 100°C for 5 hours in a convection oven. Milk permeate typically has a free moisture content of <3.00%. Total moisture is the molecule of water picked up by the molecule of lactose during the crystallization process and is perfectly stable under suitable conditions. This is measured at 100°C for 15 hours in a convection oven. Milk permeate typically has a bound moisture content of approximately 9.00%.

It is well known that Whey Permeate Powder (WPP) will undergo Maillard Browning over storage time. This is because WPP contains the milk sugar, lactose, which is a well-known reducing sugar along with free amino acids and short length, hydrolyzed protein peptides.

In the manufacture of cheese, protein hydrolysis occurs, leaving a remnant of free amino acids and small peptides that end up in the permeate (WPP) that results after filtration of the cheese whey to concentrate intact proteins. Because there are so many reactive nucleophilic amino acid groups in WPP, very little energy is required for the Maillard reaction to proceed. Therefore, the Maillard reaction can occur at ambient temperatures over time in Whey Permeate Powders.

MPP is not as likely to undergo a Maillard reaction as is WPP. Milk Permeate Powder (MPP) also contains lactose but it does not contain as many free amino acids or hydrolyzed protein peptides as WPP because the process of filtering skim milk to make MPC does not cause protein hydrolysis to occur in cheese manufacture. Therefore, the Maillard reaction does not proceed as easily with MPP. MPP will undergo Maillard reactions in applications where sufficient heat is introduced and sufficient time is allowed for the reaction to proceed. In general, however, it can be said that the Maillard reaction is less likely to occur when using MPP as an ingredient when compared to WPP.

That would depend on the application, but in general, you will probably have to modify your product formula. Maltodextrin does not have a significant mineral content while MPP contains approximately 8% mineral content. A significant portion of the MPP mineral content comes from potassium, calcium, and magnesium. These minerals can interfere with gum stabilizing systems and emulsification systems. Therefore, care must be taken to prevent the minerals from interfering with product stability by sequestering the mineral activity. Addition of sequestrant salts, such as disodium or dipotassium phosphate should help decrease mineral reactivity with the rest of the product ingredients. If the product contains iota or lambda carrageenan and/or guar gum, you might find that you can decrease gum usage levels when substituting MPP for maltodextrin, or any other ingredient with little or no mineral composition, because calcium acts synergistically with these gums to enhance gelling and water binding.

In most food product applications, lactose is used as a dairy solids filler/texturizer. Since MPP is 82% lactose, it can act as an excellent replacement for lactose as a dairy solids filler/texturizer. The primary difference between MPP and lactose is that lactose does not contain milk minerals while MPP contains approximately 8% milk mineral content. A significant portion of the MPP mineral content comes from potassium, calcium, and magnesium. These minerals can interfere with gum stabilizing systems and emulsification systems. Therefore, care must be taken to prevent the minerals from interfering with product stability by sequestering the mineral to decrease their reactivity with other ingredients. Addition of sequestrant salts, such as disodium or dipotassium phosphate should help decrease MPP mineral reactivity with the rest of the product ingredients. If the product contains iota or lambda carrageenan and/or guar gum, you might find that you can decrease gum usage levels when substituting MPP for lactose, or any other ingredient with little or no mineral composition, because calcium acts synergistically with these gums to enhance gelling and water binding.

Sweet whey powder (SWP) and skim milk powder/nonfat dry milk (SMP/NFDM) both contain significant mineral content and mineral composition is similar to MPP. SWP is almost equivalent to MPP in mineral composition while SMP/NFDM possesses a higher calcium content than MPP. You should be able to substitute MPP for SWP directly without any change in product formulation. When substituting MPP for SMP/NFDM, you might have to slightly modify your gum system and sequestering salt levels. If your product contains iota and/or lambda carrageenan or guar gum, you might have to increase the gum usage slightly to achieve desired stability when replacing SMP/NFDM. On the other hand, you might find that you can decrease usage of sequestering/emulsifying agents, such as disodium and dipotassium phosphate when replacing SMP/NFDM with MPP.

Our feed is a mixture of alfalfa hay, corn silage, grain mix, and minerals.

A full 75% of the feed to the cows is Idaho grown. Mainly corn, alfalfa, and barley are grown in Idaho and fed to our cows. The other 25% are grain by-products following removal of certain human consumption products; examples, soy and canola meal following oil removal and cotton seed following cotton fiber removal.

The protein source is plant, mainly from soy, canola, and alfalfa.

We do extensive antibiotic screening on every load of milk that arrives at Idaho Milk Products. If a load of milk is detected to contain antibiotics, that entire load of milk is rejected, as is required by law, and current protocol calls for sending that load to a digester for disposal. This program is FDA mandatory and regularly monitored by the FDA. Consequently, no milk is used for manufacture and, therefore, none of our products contain antibiotics. It is interesting to note that as of this writing, Idaho Milk Products has not had any loads received to date test positive for antibiotics. On the other hand, it is standard dairy industry practice to treat ailing cows with antibiotics to help them heal much faster, as a doctor will prescribe antibiotics for people who are ailing. These ailing cows, however, are kept isolated from healthy cows in “hospital pens” at the farms and they are milked separately from the healthy cows. Their milk is not included with milk for sale to the factory.