Formulation of a probiotic buttermilk powder using cell protectants by spray drying and estimation of its shelf-stability

Probiotic powders have received significant attention in recent times, due to their health benefits. However, the decrease in viable counts of the probiotic bacteria after spray drying and during subsequent storage remains a concern for spray-dried powders. Therefore, the proportion of the cell protectants such as whey protein concentrate (WPC), trehalose, and maltodextrin were optimised by response surface methodology to achieve high viability of bacteria in the spray-dried buttermilk powder along with evaluation of their physicochemical characteristics. The viable counts of Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus and Bifidobacterium bifidum were, respectively, 32.6, 52.2, and 50.9% lower in the control sample without protectants than in the powder containing protectants after 49 d of refrigerated storage. The optimised concentration of the thermal protectants in this study will help in the industrial production of buttermilk powder with desirable properties and an affordable cost.