Effect of temperature on growth different kefir grains and organoleptic quality of kefir

Fermented products including kefir are food products with high nutritional and biological value. Kefir culture production is given by fermentation of milk with kefir grains. The kefir grains are usually of irregular shape and rough surface with unknown origin. The typical microflora of kefir is not exactly defined so microbiological composition and organoleptic quality of kefir depends on temperature of kefir grains growth. For kefir culture preparation two kefir grains of different origin (K and N) were used. For kefir culture production skimmed milk (90 C / 15 min) inoculated with two different kefir grains (K and N) incubated about 18 hours at 20 and 22 C were used. The ready kefir cultures were inoculated in homogenised and pasteurised (90 C / 15 min) milk with 3,2 % milk fat, and fermented at 20 C. After fermentation kefir samples were kept in refrigerator (at 6 – 8 C) during nine days, and analysed at regular intervals. The K products of kefir grain culture had the greatest influence on sensory quality and negligible influence on kefir acidity during nine days of storage in refrigerator at 6 – 8 C. The sensory quality of K products kefir culture prepared at 22 C had the best scores during nine days of storage. Kefir made of each kefir cultures analysed (K20, K22, N20, N22) had a desirable viscosity during nine days of storage.