Lactic Acid Products

(soured milk products), a group of dairy products made from whole cow’s milk or its derivatives (cream, nonfat milk, whey) by self-fermentation or the addition of ferments. Lactic acid products are also made from the milk of sheep, goats, and mares.

The general preparatory process in the manufacture of all lactic acid products is the preliminary pasteurization or boiling of the milk (for varenets —fermented boiled milk), which prevents the development of harmful microorganisms. The milk is then fermented by introducing pure cultures of lactic acid bacteria or yeasts.

Lactic acid products are divided into products of lactic acid fermentation (cottage cheese, sour cream, clabber) and those of combined lactic acid and alcoholic fermentation (airan, kefir, riazhenka, acidophilus milk, koumiss). In the first group, bacteria decompose the milk’s lactose to lactic acid; this coagulates the milk’s casein, which precipitates in the form of flakes. The result is that lactic acid products are considerably more assimilable than milk. With mixed-fermentation products, the milk sugar forms not only lactic acid but also alcohol, carbon dioxide, and volatile acids. Here, too, the assimilability of lactic acid products is heightened. In terms of protein and fat content, there is practically no difference between lactic acid products and whole milk.

Because of their therapeutic and dietetic properties, lactic acid products are widely popular. They are also used in feeding animals. They are more quickly assimilated by the body than is milk, and they do not require the processing by digestive juices that milk does. (Milk is 32 percent assimilated an hour after consumption; lactic acid products are 91 percent assimilated.) The dietetic and therapeutic properties of lactic acid products are a function of the presence in them of lactic acid, a significant number of live lactic acid bacteria, and antibiotic substances with a bacteriostatic and bactericidal effect on putrefactive and pathogenic intestinal flora.

Acidophilus milk and koumiss are used for treating tuberculosis and diseases of the digestive system. Cottage cheese is used in the prevention of atherosclerosis and in diets prescribed for liver diseases and obesity.

There are both homemade and industrially produced lactic acid products. The most common of the homemade products are clabber, cottage cheese, and sour cream. Products of the sour clotted type have different local names, such as matsoni in Georgia, matsun in Armenia, and katyk in Azerbaijan.

To broaden the assortment of lactic acid products and cater to the convenience of consumers, a technology applicable to dry-milk plants has been developed for preparing dry lactic acid products (ordinary and dietetic clabber, kefir, and sour cream).