STARTER CULTURES AND FERMENTED MILK PRODUCTS

Module 17. Koumiss

Lesson 31
KOUMISS- MANUFACTURING, NUTRITIVE AND THERAPEUTIC VALUES

31.1 Introduction

Koumiss (Turkish: kimiz, Mongolian: airag) is a fermented dairy product traditionally made from mare's milk as a result of lactic-acid and alcoholic fermentation. It is a traditional drink of normands-cattle-breeders and remains important to the people of the Central Asian steppes, including the Turks, Bashkirs, Kazakhs, Kyrgyz, Mongols, Yakuts and Uzbeks. It is also known as "Milk Champagne".

31.2 History

Koumiss is native to parts of southern Russia. This product is also a traditional drink of Central Asia. The name Koumiss was derived from a tribe called Kumanes, who lived along the river Kumane in the Asiatic Steppes. In earlier days, to accelerate the fermentation of Koumiss, pieces of horse flesh or tendon or some vegetable matter were added to the mare's milk placed into bags made from the skin of lamb presumably to provide microflora needed for fermentation. Mare's milk does not coagulate at the isoelectric point of casein and hence koumiss is not considered as a curdled product. However, its modern counterpart is based on cow's milk instead of mare's. It is now widely consumed in Eastern Europe.

31.3 Type of Koumiss

Based on different concentration of lactic acid and alcohol, three types of koumiss can be prepared.

1. Weak koumiss (0.7% lactic acid, 1.0 % alcohol)

2. Ordinary koumiss (1.1% lactic acid, 1.8% alcohol)

3. Strong koumiss (1.8 % lactic acid, 2.5% alcohol)

In addition to acid and alcohol, carbon dioxide is also produced to impart fizziness to the final product.

31.4 Production of Koumiss

Koumiss is made by fermenting mare's milk. During the fermentation, Lactobacilli bacteria acidify the milk, and yeasts turn it into a carbonated and mildly alcoholic drink. Traditionally, this fermentation took place in a horse-hide container, which might be left on the top of the yurt (Figure 31.1) and turned over on occasion, or strapped to the saddle and joggled around over the course of a day's riding. Today, a wooden vat or plastic barrel may be used in place of the leather container. Other accounts from some cities in northern or western China have it that the skin, partially filled with mares' milk, is hung at the door of each home during the season for making such beverages, and passersby, who are familiar with the practice, give each such skin a good punch as they walk by, agitating the contents so that they would turn into koumiss rather than coagulate and spoil.

Fig. 31.1 Woman sitting next to a yurt

Industrial-scale production of koumiss generally uses cow's milk because of the limited availability of mare's milk even in the areas of the world where koumiss is popular today. Cow milk is richer in fat and protein but lower in lactose than the milk from a horse. Before fermentation, mare's milk has almost 40% more lactose than cow's milk. Therefore, the cow's milk is fortified in one of the several ways. Sucrose may be added, to allow a comparable fermentation. Another technique adds modified whey in order to better approximate the composition of mare's milk. During fermentation, the lactose in mare's milk is converted into lactic acid, ethanol, and carbon dioxide, and the milk becomes an accessible source of nutrition for people who are lactose intolerant. The flow diagram of manufacture of koumiss is given in Figure 31.2.

One of the essential points in the making of koumiss is that during the whole process of fermentation milk should be kept constantly agitated by stirring. This helps in incorporation of oxygen to the fermenting fluid. It also causes breaking up of the precipitated casein into very fine particles. This contributes to ease of digestibility of koumiss. Figures 31.3 and 31.4 depicts the traditional vessels used for serving koumiss as well as a traditional way of pouring the product.

Fig. 31.2 Preparation of Koumiss

31.5 Starter Cultures

In the early days koumiss from a previous batch was used as starter. Nowadays purified starters are being used for the production of koumiss. It mainly comprised of L. bulgaricus and Saccharomyces lactis. Various strains of lactic acid bacteria and yeasts have been isolated from commercial koumiss viz., Lactobacillus delbruckei subsp. bulgaricus, Lactobacillus paracasei subsp paracasei, Lactobacillus rhamnosus, Lactobacillus paracasei subsp tolerans, Candida kefir and Kluyveromyces marxianus subsp lactis. It is also possible to find lactic streptococci, coliforms and some spore forming bacilli in koumiss.

31.6 Nutritive and Therapeutic Advantages of Koumiss

Koumiss has almost a similar nutritive value as the milk from which it is prepared except that during the making of koumiss, the sugar has been to a large extent replaced by lactic acid, alcohol and carbon dioxide gas. The casein has been partly precipitated in a state of very fine division and partly predigested and dissolved. There was not much change in fat and salts. The acid and alcohol produced help in the process of digestion and ease of absorption of fat and minerals. Nutritive and stimulating qualities of Koumiss render it very valuable for nursing females. Koumiss is considered to be a refreshing therapeutic drink. In USSR, this preparation is used for the treatment of pulmonary tuberculosis. Koumiss possesses diuretic properties and helps in restraining intestinal putrefaction. Koumiss has been and is employed with success in diabetes.

Koumiss has been described as the greatest of the fermented milk. In terms of experience and traditional manner of consumption this effervescent acidic, alcoholic fermented milk is comparable to beer and is well known for its therapeutic benefits. Koumiss can be a promising carrier of currently-in-use and future probiotic microorganisms which could provide consumers with health benefits beyond traditional nutrition, thus contributing to sustaining human health and well-being.