How is the quality of milk protein is assessed?

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.