Effect of Selenium Nanoparticles on Physicochemical Profile and Shelf-Life of Fermented Dairy Drinks

The article describes the synthesis of selenium nanoparticles by chemical reduction in an aqueous medium using selenious acid as a precursor, nonionic surfactant Kolliphor HS15 as a stabilizer, and ascorbic acid as a reducing agent. The new acidophilic fermented dairy drink contained a starter based on a pure culture of Lactobacillus acidophilus. It was fortified with selenium nanoparticles at the rate of 30 % of recommended daily intake for adult consumers. The experimental drink had a slightly viscous consistency but tasted and smelled like pure fermented milk. Nanoselenium had no effect on the quality, physicochemical parameters, storage capacity, and sensory profile of the experimental fermented dairy drink. The changes in titratable and active acidity were studied during storage by potentiometric and titrimetric methods, respectively. The active acidity of the medium and the titratable acidity at the end of shelf-life corresponded to State Standard GOST 32923-2014 for fermented milk products fortified with probiotic microorganisms. The method of microscopy made it possible to study the effect of selenium nanoparticles stabilized by Kolliphor HS15 on the growth of Lactobacillus acidophilus. Nanoselenium stimulated the growth of Lactobacillus acidophilus: the experimental fermented dairy drink demonstrated a significant increase in lactic acid bacterial count compared to the control sample.