Studying the Effect of Refrigerated Storage on the Vability of Native and Industrial Probiotic Strains and Some Physico-chemical and Sensory Properties in Cornelian Cherry Juice

Recently, an increased demand for nondairy probiotic products comes from the popularity of vegetarianism, lactose intolerance, and high cholesterol content in dairy products. The objective of this study is evaluating the effect of refrigerated study on the viability of probiotics and some physicochemical characteristics in cornelian cherry juice. Cornelian cherry juice with natural and adjusted pH with sodium bicarbonate was inoculated with three industrial bacteria (L. rhamnosus, L. plantarom and L. casei) and two native probiotic bacteria (L. casei) (108 cfu/ml). Then the samples were placed in the refrigerator (4°C) immediately after inoculation. Next, the changes in chemical characteristics such as pH, acidity, phenolic compounds content, anthocyanin content, antioxidant activity, microbial characteristics (such as enumeration of live probiotic cells), and sensory properties were evaluated during 4 weeks with the time intervals of one week for the samples with adjusted pH. Significant differences between the averages of obtained data were checked by one way ANOVA test. Also differences between the averages of each treatment during the refrigerating time were examined by repeated measure test using SPSS software at the significant level of 0.05. Data analysis showed that treatment type, storage period and interaction effect of these two factors have significant effects on the changes of physicochemical characteristics and probiotic viability (P<0.05). The results revealed that native probiotic strain L. casei spp. T4 compared to other strains maintained its viability at 8.67 log cfu/ml after 4 weeks of refrigerated storage. Also there were the most changes in physicochemical characteristics in the cornelian cherry treatments containing this strain, which is a marker of fermentative activity during the refrigerated storage. The results showed that cornelian cherry juice because of low pH and presence of inhibitor phenolic compounds has negative effect on viability of probiotics, especially industrial strains during the refrigerated storage.