What are key factors that dictate stability?

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…

What is suspension stability and how is it measured?

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…

Is solubility a reflection of quality?

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…

What are typical NSI and WPNI results for MPC powders?

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…

What is NSI and WPNI?

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…

How is solubility of Dairy Proteins measured?

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…

Sensory properties of MPCs and MPIs

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…

What exactly causes Maillard browning?

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…

What is a Maillard Reaction?

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…

Are different heat treatments used in manufacturing MPCs?

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…