Effect of molasses on the viability of probiotic bacteria and some properties of probiotic yogurts

In this study, the effects of 3 different molasses types (carob, mulberry and grape) on the physicochemical, sensory and structural properties of yoghurts and the viability of probiotic bacteria (Bifidobacterium animalis subsp. lactis BB-12®) were investigated. Yogurt samples, which are the study material, were produced using cow's milk, yogurt culture and probiotic culture. Each type of molasses was used at 5% and 7% rates. 14 yoghurt samples with and without probiotics were produced from milk with and without molasses. Yogurt samples were stored at +4 °C for 21 days and physicochemical, structural, microbiological and sensory analyses were carried out on the 1st, 7th, 14th and 21st days of storage. Sterptococcus thermophilus and Bifidobacterium animalis subsp. lactis BB-12 enumaration, dry matter, fat, color, titratable acidity, pH, water holding capacity, viscosity, texture profile analysis and sensory analyses were performed on yoghurt samples. According to the results obtained in the study, the dry matter values of the yoghurt samples with molasses were higher than those without molasses. The pH values of all samples decreased with time and their acidity values increased. However, the pH and acidity values of yoghurt samples containing probiotics were higher than those of yoghurt samples without probiotics. The water holding capacity, viscosity and hardness of yoghurt samples decreased slightly with the addition of molasses. Among the yogurt samples with molasses, the highest water retention capacity was found in yogurts with carob molasses. Addition of molasses to yoghurt did not have a positive effect on the survival of S. thermophilus. Only 7% mulberry molasses had a positive effect on the vitality of B. animalis. Only 7% mulberry molasses addition had a positive effect on the vitality of B. animalis subsp. lactis BB-12. However, at the end of storage, the S. thermophilus and B. animalis subsp. lactis BB-12 counts of all samples were above the 8 log value. These results meet the live starter and probiotic number requirements for the fermented and probiotic product. As a result of the sensory analysis, it was observed that yogurt samples without molasses were preferred more than those containing molasses. Control samples without molasses received the highest scores for all sensory criteria examined by the panelists.