3.2. Dairy Industry

Milk itself contains a large number of enzymes, some of which are important in milk processing:

• naturally occuring proteases - contribute for the flavour characteristics of the cheese
• naturally occuring lipases - frequently lead to the development of rancidity in products containing milk fat.

The two major uses of enzyme technology in the dairy industry are:

1) The hydrolysis of  lactose.

2) The use of rennets in the milk coagulation:

Calf rennet is the most used rennet. The active enzyme present is an acid protease, designated as rennin or chymosin.

The microbial rennets have already been accepted in most countries as alternative coagulants in the production of a number of cheeses.

Another application is the use of calf chymosin produced by recombinant microorganisms like yeasts.

There are however other particular applications of enzyme technology in the production of highly specialized milk products.

Enzyme-modified cheeses are produced by addition of individual or multiple lipase and proteinase enzyme preparations to natural cheeses in order to accelerate the natural biochemical changes involved in traditional cheese ripening.

• adequate blends of microbial lipases are used to produce low-carbon-chain-length fatty (volatile) acids to confer strong cheese flavour to the product
• the neutral fungal proteinase is suited for the generation of strong savoury flavour without bitterness.

Enzyme-modified cheese makes it possible for the food technologist to:

• increase a product's flavour intensity, without increasing the cheese solid content

• or to reduce cheese solid content for production of "healthier" (low-fat) products, whilst maintaining the original flavour intensity of the product.

The degree of modification can be controlled to develop a variety of:

• flavour profiles
• product compositions
• product forms

Enzyme modified cheese products are used in processed cheese, cheese spreads, cheese dips, cheese snacks, biscuits and cheese cake.

Several methods for accelerating cheese ripening are being presently investigated in order to minimize storage costs, which represent a significant proportion of the total production process cost.