Food Safety Standard

Functional properties of Dairy Ingredients

What do we mean by functional properties?

The functional properties of dairy ingredients may be defined in relation to their performance as ingredients in final product or formulated foods.
The functional properties of the ingredients are those properties, which provide specific function in the final products. Functional properties determine the overall behavior of ingredients in foods during processing, applications, storage and consumption.
Functional properties of a particular ingredient determine their end-use in the final product
The functional properties of dairy ingredient typically dependent upon:
- Type and composition of ingredients (e.g., WPC/WPI/MPC/caseinates)
- Processing conditions- Primary processing (during ingredient making) and secondary processing (during formulations)
- Formulations/ Final product (e.g., beverage, soup, sauces, ice cream, bakery)

What is Solubility?

It is an ability of dairy ingredients to readily go in the solution and remain soluble under different processing conditions such as heat treatments or in different formulations such different pH or mineral levels.

Why is it important?

During reconstitution or while making beverages, complete solubalization or rehydration of dairy ingredients is very important

To avoid defects (e.g., chalkiness/Gritty texture)
To avoid settling of floating of particles
To provide desired nutritional and functional benefits

Several factors can affect reconstitution of dairy ingredients

Water quality (Hardness, mineral content etc.)
Reconstitution temperature
pH of the solvent
Other component present in the solvent (e.g., sugar, competition with other components, availability and mobility of water)
Particle chemistry surface composition e.g., fat on surface, surface charge (hydrophilic or Hydrophobic, denaturation and aggregation of proteins)
Particle morphology‐particle size and shape, agglomeration, porosity, surface area, etc.

What is heat stability?

Heat stability can be defined as an ability of a given sample to withstand UHT sterilization (140-145°C/ 4-5s) or retort temperatures (120°C/ 20 min) without coagulation, precipitation or excessive thickening/gelation/viscosity increase.

What is Emulsification?

In the process of making oil-in-water emulsions, oil/water interfaces are created. These interfaces are protected by adsorption of surfactants and partially lost again by recoalescence of those emulsion droplets that are not protected quickly enough by surfactants.

Foamability/Whip ability

Foaming/ whipping is defined as the creation and stabilization of gas bubbles in a liquid.
Milk proteins have surface-active properties. Milk proteins easily adsorb on fat globule interfaces during homogenization and to the air water interface during whipping. It is well known that both caseins and whey proteins have excellent surface-active properties
Dairy ingredient such as WPC, WPI, MPC and skim milk powders are beneficial in the development of foam/ incorporation of air. e.g., during manufacture of Ice cream, frozen desserts, whipped toppings, meringues, mousses and cakes

The whipping properties of dairy protein ingredients are affected by many factors, such as:

Concentration and state of the dairy proteins,
pH
Ionic environment
(pre-) heat treatment and
the presence of lipids

As dairy protein concentration increases, foams become denser with more uniform air bubbles of a finer texture. Generally, overrun increases with protein concentration to a maximum value after which it decreases again.

Viscosity

Dairy ingredients play an important role in controlling the texture/modifying the rheological properties of foods.
Viscosity development is closely related to gelation properties
Dependent upon the state of the protein, dairy proteins can contribute a desired viscosity to a wide range of foods such as:

Soups, Sauces, Salad dressings, Batters and Yogurts

Water binding

The amount of water held in a gel under a given set of conditions is referred to as its water‐holding or water‐binding capacity.
It is possible to achieve desired water binding when dairy ingredients such as MPC, WPC, WPI and milk powders are used in viscous food products such as beverages, soups, sausages and custards.
The water binding and associated properties (i.e., swelling, gelation and viscosity) of proteins are the major determinants of texture in a number of processed food products such as cheese, yogurt and reduced‐fat dairy foods.
The water enclosed in the gel’s three-dimensional structure, can reduce the cost of food (as water is inexpensive) and can also improve sensory perception.

Gelation

Dairy proteins, have the ability to form rigid, heat‐induced irreversible gels that hold water and fat, and provide structural support.
Gelation is a two‐step mechanism that involves an initiation step, the unfolding or dissociation of protein molecules, followed by an aggregation step in which association or aggregation reactions occur, resulting in gel formation.

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