26 Vol. 24, No. 1: 26–32 Czech J. Food Sci. Kefir is a unique and refreshing fermented milk product with defined health promoting benefits (FURUKAWA et al . 1990, 1991; CEVIKBAS et al . 1994; ZACCONI et al. 1995; ZUBILLAGA et al. 2001). The word of kefir is said to have originated from the Turkish word ‘Keyif’ for ‘good feeling’ due to the overall sense of health and well being when consumed. It originates in the Caucasus Moun- tains in the former Soviet Union, in Central Asia, and has been consumed as a traditional drink for thousands of years in these countries. In Turkey, kefir is currently available for retail sale; however, real kefir is produced only by traditional methods at home (OTLES & CAGINDI 2003). Kefir is distinguished from the more known fermented milk yogurt in that it is the product of fermentation of milk carried out only with kefir grains or with mother cultures prepared from the grains. The grains contain a relatively stable and specific balance of a complex mixture of both bac- teria and yeasts held together by a polysaccharide matrix. Out of the microbial components of the grains, the genera most frequently reported are homo-fermentative and hetero-fermentative lacto- bacilli, lactococci, leuconostoc, acetobacteria, and yeasts (both lactose-fermenting and non-lactose- fermenting) (ANGULO et al . 1993; GARROTE et al . 1998; LIN et al . 1999; SIMOVA et al . 2002). The lactic acid bacteria and yeast fermentation of milk results in the production of numerous components, including lactic acid, CO 2 , a small amount of alcohol, and an array of aromatic mol- ecules, all of which participate in providing kefir with its unique organoleptic characteristics; fizzy, slightly acidic and alcoholic taste, as well as the contents of antibiotics and bactericides that inhibit the growth of undesirable and pathogenic micro- organisms in kefir milk (ANONYMOUS 1992). The ready-to-serve kefir drink contains lactic acid, mainly the L(+) form, of about 0.6–0.9%, as well as formic, succinic and propionic acids, 50% volume CO 2 , 0.6–0.8% ethyl alcohol, different The Sensory Characteristics of Berry-Flavoured Kefir LÜTFIYE YILMAZ, TÜLAY ÖZC AN YILSAY and ARZU AKPINAR BAYIZIT Department of Food Engineering, Faculty of Agriculture, Uludag University, Görükle, Bursa, Turkey Abstract YILMAZ L., ÖZCAN YILSAY T., AKPINAR BAYIZIT A. (2006): The sensory characteristics of berry-flavoured kefir. Czech J. Food Sci., 24: 26–32. Certain physicochemical and sensory characteristics of the flavoured kefir drink were studied during refrigerated storage. Kefir drink batches were prepared using 2% addition of kefir grains, incubation for 18 h and subsequent filtration. The batches were then flavoured with blackberry, raspberry and strawberry aromas in the concentrations of 0.05, 0.10 and 0.15%, respectively. The samples were taken for analysis on 1 st , 4 th , 7 th , and 10 th days of storage at 4 ± 1°C. The sensory analysis of the flavoured kefir samples revealed the best acceptability level on the 4 th day of storage. Nevertheless, the samples were acceptable all throughout the storage. The percentage of the aroma addition significantly influenced the odour, flavour, texture, and mouth-feel, and the overall acceptability ratings. The higher percentage of the added aroma the more sensed, however, the lowest aroma addition was preferable. The pHs of the flavoured kefir drinks decreased throughout the storage time whereas, the titratable acidity, alcohol content and CO 2 values increased. Keywords: kefir; physicochemical parameters; sensory characteristics