Dairy produts.

Explanation

Since ancient days, milk is converted into various products for its preservation.
(ii) Water content and acidity of the milk changes during formation of these products and texture, taste and flavour is improved.
(iii) Bacteria in milk is used for most milk products . Milk is pasteurized at the beginning to destroy unwanted microbes .
(iv) These processes are performed on a large scale with more skill.
(v) Milk is fermented with the help of lactobacilli. Lactose sugar of the milk is converted into lactic acid .
(vi) Milk proteins are coagulated with the help of lactic acid .
(vii) Compounds with taste and flavour are also formed . e.g. Diacetyl has the flavour of butter.