Sanket Borad

Effect of processing on nutritive values of milk protein

ABSTRACT Milk is an essential source of nutritionally excellent quality protein in human, particularly in vegan diet. Before consumption, milk is invariably processed depending upon final product requirement. This processing may alter the nutritive value of protein in a significant manner. The processing operations like thermal treatment, chemical treatment, biochemical processing, physical treatments, nonconventional treatments, etc. may exert positive or negative influence on nutritional quality of milk proteins. On one side, processing enhances the nutritive and therapeutic values of protein while on other side intermediate or end products generated during protein reactions may cause toxicity and/or antigenicity upon consumption at elevated level. The review discusses the changes occurring in nutritive quality of milk proteins under the influence of various processing operations.

Development of protein fortified mango based ready-to-serve beverage

Fruit drinks contain negligible amount of protein as nutritional component. Fortification of fruit drinks with protein is a challenge due to protein stability in acidic and ionic environment. Mango ready-to-serve (RTS) beverage was fortified with modified whey protein and its rheological properties were studied. Whey protein was hydrolysed with papain to improve its stability in acidic medium. The water holding capacity of whey protein increased about two times after hydrolysis. Hydrolysed and native whey protein was used at 2, 3 and 4% levels for fortification of mango based RTS beverage. Addition of hydrolysed whey protein at all the three levels did not significantly change the flow behaviour of the beverage. Native whey protein fortification resulted in precipitation; however, addition of hydrolysed whey protein led to stable beverage formulation at all the three levels. Hydrolysed whey protein imparted slight bitter taste to the RTS beverage, which was masked by β-cyclodextrin @ 0.15% of total protein. The mango RTS beverage with 3.0% hydrolysed whey protein was found acceptable with good sensory appeal and stability during thermal processing as well storage in glass bottles.

Application of ohmic heating for concentration of milk

The concentration of milk through evaporation is the most commonly employed unit operation for the production of a wide array of traditional and industrial dairy products. Major problems associated with thermal evaporation are a loss of aroma, flavor and color change. Ohmic heating (OH) has an immense potential for rapid and uniform heating of liquid, semi-solid and particulate foods, yielding microbiologically safe and high-quality product. The effect of ohmic heating on physico-chemical, rheological, sensorial and microbial properties during concentration of cow milk, buffalo milk and mixed milk (50:50) was studied and compared to conventional evaporation. OH significantly increased free fatty acids (FFA), apparent viscosity, hydroxymethylfurfural (HMF) content, instrumental color values i.e. redness (a*) and yellowness (b*) values. However, pH value and whiteness (L*) of the concentrated milk decreased significantly. OH caused a drastic reduction in microbiological counts and treated milk can be kept for a longer period.