Frequently Asked Questions
Skimmed milk powder is defined by Codex Alimentarius. Nonfat dry milk is defined by the Code of Federal Regulations. The main difference between the products is the adjustment of protein level. The protein content of SMP can be adjusted by the addition of milk retentate, milk permeate, or lactose. The protein content of SMP is typically lower than the protein content of NFDM.
A supplier listing for all dairy ingredients is located at ThinkUSAdairy. Select "Supplier Search" to start your search and then select the ingredient you are looking for.
Typically you would make the selection by looking at the total composition and the cost of each ingredient and think about what application you want to use it in. For instance, a WPC80 will have about 5-7% fat, 4-5% lactose, and 4% ash. Compare that to a WPI, which will have less than 1% fat, about 1% lactose, and 2% ash. A WPC80 will be less expensive than a WPI. If you are not concerned about the fat and lactose in a WPC80 then use it to fortify with protein. WPC80 can have more flavors associated with the fat, which may or may not be desirable for your application. If you are trying to make a low pH clear drink then a WPI is the only ingredient that will provide good clarity.
A listing of starting formulas for main dishes, appetizers, sauces, beverages, desserts, etc. are located at ThinkUSAdairy. Select “Nutrition & Trends” to start your search and then select “Eating Occasions.” You may select “Breakfast,” “Snacking,” “Dining Out,” or “Working Out.” Under each unit, you will find a “Formulas & Recipes” section that lists “(the name of the unit) – view all applications.” You may click and select industry segment, and/or application and/or dairy product and/or specialty/focus. You may then search for results where you can view all applications.
Here are a couple of resources from ThinkUSAdairy that you might find helpful. There is a “Dairy Detective” article, authored by CDR's Susan Larson, which gives a general overview of using whey proteins to replace egg protein. There is also a downloadable resource titled “Whey Protein as an Egg Replacer Guidelines.” Another helpful resource is this monograph on how whey can be used in baked goods.
You should remember that different dairy ingredients have unique characteristics and they do not behave the same in all food systems. For many uses, it is critical to hydrate the powders. Whey proteins hydrate much faster than the casein proteins. Good hydration of milk protein powders is key to their performance in low-acid (neutral pH) beverages. It is important to dissolve the powders in a solution. The temperature of the liquid influences the rate of hydration. Higher temperatures increase the rate of hydration. A high-speed mixer will help disperse the powders, but allowing time for the powders to absorb the liquid is also important to optimize their heat stability and solubility over the shelf life of the beverage. Proper storage of dairy powders will insure their best performance. For instance, studies of whey protein concentrate with 85% protein (MPC85) have found that losses in solubility occurred within 60 days at storage temperatures of 30°C (86°F) and above. Working with the best quality materials helps insure the finest finished product.
Permeate is a byproduct of the production of whey protein concentrate (WPC), ultrafiltered (UF) milk or milk protein concentrate (MPC). The composition of permeate will vary depending on the starting material. Permeate is mainly composed of lactose and mineral and has little to no true protein.
There are two sources of permeate: milk permeate and whey permeate. Whey permeate comes from the ultrafiltration of whey, that is the result of the cheesemaking process, while milk permeate comes from the ultrafiltration of skim milk. Ultrafiltration of whey or milk concentrates the larger molecules, such as protein and fat, which becomes the retentate (the components that are retained by the ultrafiltration membrane). The retentate becomes the protein-based ingredients, like whey protein or milk protein concentrates or isolates (WPC, WPI, MPC, MPI). Lactose, and minerals are the smaller molecules which go through or “permeate” the ultrafiltration membrane, and thus are called the permeate. Both milk and whey permeates contain primarily lactose and minerals. Permeates contain very little fat or protein. Whey permeate and milk permeate are very similar; the main difference being that milk permeate hasn’t gone through cheesemaking process. Therefore, milk permeate has a cleaner, milkier flavor while whey permeate picks up some flavors from the cheesemaking process.For more information, see this overview on whey and milk permeate.
Permeate may be used in formulas as a cost-reduction opportunity and it may also be used for sodium reduction. However, the high-mineral content often gives a salty taste perception. In addition, because of the high-lactose content, there is also a sweet flavor perception. This monograph on permeate gives some direction on how to use permeate in a formula to replace salt and includes some starter recipes.
Permeate is largely made up of lactose. Lactose has a maximum solubility of about 14%. A gritty texture will indict that not all of the lactose in the formula is completely soluble. In this case, the amount of permeate in the formula should be decreased.
The staff at CDR will work with companies and individuals to develop new product ideas or new flavors or modifications of current products that are dairy based. The CDR Dairy Ingredients and Cultured Products Staff has experience working with large and small companies to develop products. The staff also has product development experience from working in the food industry. Initial discussions will clarify the concept and basic cost. We will explore the concept and match it with our capabilities and expertise. Confidentiality and fee-for-service documents can be prepared. You should visit the CDR Working With Us webpage.
This Dairy Pipeline article (see page 4) discusses whey protein and milk protein and the differences between concentrates and isolates. The article discusses the functionality differences of the different proteins and their strengths and differences.
DLP and mother liquor both refer to the ingredient remaining after the lactose crystallization process. This product is typically sold in a liquid form for animal feed. It contains lactose, minerals, water, and non-protein nitrogen but its composition is not defined. The lactose process with DLP identified can be found on page 88 of the 2nd edition of the Dried Dairy Ingredient Handbook written by Dr. Karen Smith (CDR Dairy Processing Technologist) and provided as part of the ADPI Industry Standards Handbook. Dairy product solids is the industry term used for permeate ingredients produced as a co-product by the ultrafiltration of milk or whey to produced milk protein concentrates and isolates or whey protein concentrates or isolates. ADPI has published an industry standard for dairy permeate (compositions below) and there is also a Codex Standard for permeate.
Buttermilk powder (21 CFR 101.4 (b)(6)) and nonfat dry milk (21 CFR 131.125) both have standards of identity in the Code of Federal Regulations. Buttermilk powder is included in two different product definitions:
- Dry buttermilk is the product resulting from the removal of water from liquid buttermilk derived from the churning of butter. It shall contain not less than 4.5% milkfat and not more than 5% moisture. Dry buttermilk shall have a protein content of not less than 30%.
- Dry buttermilk product is the product resulting from the removal of water from liquid buttermilk derived from the churning of butter. It shall contain not less than 4.5% milkfat and not more than 5% moisture. Dry buttermilk product contains less than 30% protein, the label of which should specify the minimum protein content.
Nonfat dry milk (NFDM) is the product resulting from the removal of fat and water from milk and contains the lactose, milk proteins, and milk minerals in the same relative proportions as in the fresh milk from which it was made. It contains not over 5% by weight of moisture.
Many factors contribute to off flavor development in stored dried dairy ingredients. Each dairy ingredient, whether it is processed from milk or whey, has a characteristic flavor profile that comes from the original fluid ingredient. The quality of the fluid milk or whey is influenced by the source of the fluid product (milk or whey source), processing, storage conditions, microbial content, and composition. All of these factors can lead to compounds such as by-products of the Maillard browning reaction or other chemical reactions that leave compounds that will be susceptible to off flavor development in storage, especially at temperatures that are above ambient temperatures (75°F, ~24°C). Warm temperatures >75°F and humid conditions (>75% relative humidity) will contribute to an increase in browning of dried dairy ingredients, which will also contribute to more caramelized and burnt flavors. Elevated temperatures and humidity will also increase flavors associated with fat oxidation, such as stale, cardboard off flavors. More about off flavor development in dairy powders can be found in the following two references.
- Determination of the sensory attributes of dried milk powders and dairy ingredients, M.A. Drake, Y. Karagul-Yuceer, K.R. Cadwallader, C.V. Civille, and P.S. Tong, Y. of Sensory Studies 18 (2003) 199-216.
- Technical Report: Sensory properties of whey ingredients, K. Burrington, U.S. Dairy Export Council, January 2012.
Permeate can be used to replace sweet whey, as a partial replacement for skim milk powder or nonfat dry milk, as a clean label replacement for carbohydrates such as maltodextrin or dextrose, as a source of carbohydrate and electrolytes for an isotonic drink, as an ingredient that provides carbohydrates and dairy minerals for nutritional applications, or as an ingredient to help reduce sodium.
- Burrington, K. Applications Monograph: Permeate for Sodium Reduction. U.S. Dairy Export Council, January, 2011.
- Burrington, K., Schoenfuss, T., and Patel, S. Technical Report: Co-products of Milk and Whey Processing. U.S. Dairy Export Council, May, 2014.
The total protein content of milk protein concentrates and isolates is higher than NFDM or SMP but the ratio of casein to whey protein (approximately 80% casein to 20% whey protein) or (4:1, casein:whey protein) is the same in all of these ingredients.
- Patel, H, and Patel, S. Milk Protein Concentrates: Manufacturing and Applications. U.S. Dairy Export Council, May 2014