Effect of banana puree on the survival of Lactobacillus casei in banana and apple juice cocktail during storage

Probiotic juice is one of the great innovations in various kinds of healthy drink businesses. The aim of this study was to investigate the effect of banana puree on the survival of Lactobacillus casei and physicochemical and sensory properties of cocktail containing banana and apple juice during storage. For the purpose of the study, 7% and 15% banana puree were added to apple juice in three phases. After adding banana puree, the sugar content of fruit juice was estimated as 13 °Bx. The produced fruit juice was pasteurized at 90 ˚C for 2 min. Then, depending on the treatment, L. casei was added to some samples. The samples were examined under four conservation periods (i.e., 1, 20, 40, and 60 days). The results of the study showed that the level of L. casei decreased significantly during storage time in all treatments; however, it was significantly less than the number of those of control treatments containing banana puree. The enhancement of banana puree was accompanied with the elevation of pH and significant reduction of acidity and sugar content. The treatment groups containing probiotic showed a higher increase in pH and decrease in acidity level and sugar content, compared to the groups without probiotic. The results obtained from sensory evaluation indicated that with the enhancement of banana puree to 15%, the flavor and color levels decreased significantly. As the findings indicated, the use of probiotic showed no significant effect on flavor and color levels in juice. Therefore, it is recommended to use 7% banana puree with a storage duration of 20 days to produce cocktail juice containing apple juice and banana puree with L. casei.