The effect of xanthan gum on the development of some probiotic bacteria

In this study, the effect of xanthan gum on the development of Bifidobacterium animalis subsp. lactis and Lactobacillus casei in vitro fermentation medium was investigated. Probiotic yogurt enriched with xanthan gum as potential prebiotic source was produced and quality parameters were examined during storage. During fermentation, it was determined that pH values decreased in the medium containing different substrate sources. B. lactis and Lb. casei species were found to be able to improve acidity by growing in the medium containing xanthan gum. The average OD values of B. lactis in the medium containing different substrate sources during fermentation were ranged from 0,244 to 0,747; for Lb. casei the OD values of ranged from 0,311 to 1,332. The average B. lactis counts at during fermentation was ranged from 7,11 to 7,83 log10 cfu/mL and the average Lb. casei counts ranged from 7,49 to 8,75 log10 cfu/mL. During fermentation, OD values and average number of microorganisms increased in the samples containing xanthan gum. The number of prebiotic activities (PAS) of Lb. casei in the medium containing xanthan gum was higher than inulin, for B. lactis, it was found to be lower than inulin. When examined the amounts of lactic acid and SCFA were analyzed during 48 hour -fermentation, both bacteria were able to produce these acids. It was determined that the amount of SCFA produced depending on the bacterial species and substrate types used were also different. According to the results of microbiological analysis of probiotic yogurts examined; B. lactis counts ranged from 8,05 to 9,70 log10 cfu/g and Lb. casei counts ranged from 9,47 to 10,10 log10 cfu/g. Throughout storage the minimum acidity value was found for BL sample with 0,74% and the maximum acidity value was found for LC sample with 1,12%. Whey separation values of the samples during storage were between 0,00 and 12,00 mL/25 g. The addition of xanthan gum was found to reduce whey separation values in the samples. As a result of color analysis, it was found that addition of gum during storage reduced the L* and b* values of both yoghurts and increased the a* values. Examining the results of the texture analysis of samples, consistency and cohesiveness values increased during storage and viscosity index values decreased. As a result of the sensory analysis, it was found that the samples containing xanthan gum for all parameters were less accepted by the panelists. According to the results of in vitro analysis, xanthan gum may be a potential prebiotic source. With the use of yogurt production, it has been determined that it can be used as an ingredient to support the development of probiotics in addition to its other techno-functional properties.