TECHNICAL CHALLENGES IN CHOLESTEROL REMOVAL FROM DAIRY PRODUCTS

Milk is a natural complex system present as oil in water emulsion.
The natural organisation of milk fat globules is stabilized by the presence of
a natural membrane, called the milk fat globule membrane. It has tripartite
structure consisting of a monolayer facing the inner triacylglycerol core and
an external bilayer. Apart from giving the nutritive value, milk fat globule
membrane also contributes towards the techno-functional properties of the
dairy products. The milk fat globule membrane is composed of both polar
lipids and proteins. Cholesterol is also present in milk fat globule membrane
and accounts for about 2% of milk fat globule membrane. Increased consumer
awareness has created a perceived demand for low cholesterol products. The
World Health Organization and American Heart Association has also recommended that consumers
reduce their consumption of saturated fatty acids and cholesterol to lower the risk of coronary heart disease. Therefore, many researchers have developed different methods for reducing cholesterol
in dairy and food products. These methods include physical process (vacuum steam distillation, short
path molecular distillation and supercritical fluid extraction), biological process (cholesterol reductase and cholesterol oxidase), complexation method (adsorption with saponin, digitonin and cyclodextrin)
and chemical process. Most of these methods are very efficient in process of cholesterol removal. However, most of these methods have various drawbacks for application in dairy industry like, formation of toxic oxidation products, denaturation of proteins, loss of low molecular weight triglycerides, loss of volatile components, loss of flavour compounds etc. This leads to loss of
nutritive value of dairy products. Thus, the objectives of cholesterol removal from milk and milk
products should be, firstly focusing on the maximum cholesterol removal, secondly maintaining the nutritional quality comparable to the control and thirdly the process of cholesterol removal should not
compromise the techno functional properties of the dairy products.