Sensory, physicochemical and microbiological properties of set-type kefir produced from different dry matter ratio milk with starter culture and kefir grain

In this study, using two different kefir cultures, set type kefir production from milk containing different ratio of non-fat dry matter was investigated. For this purpose, non-fat dry matter content of milk was adjusted to 9 %, 11 %, 13 % and 15 % and kefir was produced by inoculating milks with both culture obtained from kefir grain and starter culture. Set type kefir samples were stored at +4 °C and sensory, physicochemical and microbiological properties of kefir were investigated with analysis carried out on the 1st, 8th and 15th day of storage. According to the results it was determined that dry matter content, fat content, pH, water-holding capacity and viscosity values of all kefir samples decreased while titrable acidity of samples increased during storage. Besides, total bacteria and yeast counts of samples decreased after 8th days of storage. Furthermore, depending on the storage period, a decrease in the sensory qualities of kefir samples was observed. Dry matter, titrable acidity, water-holding capacity and viscosity values were higher for kefir samples produced with starter culture while fat content, total bacteria and yeast counts were higher for kefir samples produced with kefir grain. Moreover, sensory evaluation of kefir produced with starter culture got higher scores than grain kefir samples. It was also determined that protein content, titrable acidity, water holding capasity, viscosity and yeast count of kefir samples increased with the increasing rates of non-fat dry matter. KEYWORDS: Kefir grain, kefir starter culture, non-fat dry matter of milk, set type kefir.