Microbiological, Chemical and Sensory Characteristics of Kefir Prepared with Various Fruit Additives

In this study, effects of kefir on the chemical (titratable acidity and pH), microbiological (Lactobacillusspp., Lactococcusspp. and yeast counts)and sensory properties of kefir that was prepared with fruits (strawberry, apricots, banana) (at a ratio of 20%) during the incubation (checked at 0, 3, 6, 9, 12, 15, 18 and 21 hours)and storage (checked at 1, 2, 3, 4, 5, 6, 7 and 14 days)periods were investigated. Significant differences (p<0.05) were found in the analysis of the characteristics of the different kinds of fruit kefir when compared with plain kefir. Differences were found both between the kinds of fruit and the time points at which the samples were analyzed. At the end of the incubation and storage periods, Lactobacillusspp. andLactococcusspp. counts were found to be higher in the fruit kefirs than in plain kefir. At the end of the incubation stage, apricot kefir had the highest acidity (0.73) and strawberry kefir and apricot kefir had the lowest pH (5.80). The yeast count was found to be the highest in apricot kefir (5.00 log10cfu/ml) and the lowest in banana kefir (4.00 log10cfu/ml). At the end of the storage period (at +4 °C), apricotskefir (0.70) had the highest acidity and the pH level was higher in all fruit kefirs when compared with plain kefir (5.20). Yeast counts were found to be the lowest in apricot kefir (3.04 log10cfu/ml). Comparison of fruit kefirs with sensory analysis failed to identify any statistically significant effect of the fruit on the sensory characteristics, but the best-liked types were banana and plain kefir. We proved that the added varieties of fruit affected the pH and acidity levels of the kefir and also influenced the development of microflora, so we concluded that this could consequently affect the product’s shelf life