Fermented Milk Beverages Fortified with Soy Protein

Abstract

Introduction. Fermented milk beverages with various vegetable additives expand the range of functional foods with probiotics, vitamins, and minerals. The research objective was to develop a new technology for fermented milk drinks fortified with soy protein. Study objects and methods. Heat-treated cow’s milk with Direct Vat Set bacterial starter served as the control sample, while the experimental samples featured fermented milk fortified with soy additives. The soy protein ingredient was obtained from powdered sprouted soybean. Soybeans were pre-germinated in a thermostat at 26°C for 24 h and blanched with steam for 15 min. After that, 1–9% of the soy substance was added to pasteurized milk and fermented at 38–40°C for 6–8 h. The resulting sample was tested for quality indicators and physicochemical composition. Results and discussion. The best sensory properties belonged to the sample with 5% mass fraction of the soy additive. As a result, the soy-fortified beverages entitled Bifivit and Immunovit had a better nutritional value: protein – by 1.92 and 1.79 g, fat – by 0.77 and 0.75 g, vitamin E – by 0.16 mg, choline – by 23.82 mg, potassium – by 149 mg, phosphorus – by 19 and 22 mg, calcium – by 25 and 24 mg, magnesium – by 22 and 23 mg, respectively. One portion (100 g) of these drinks contained over 15% of recommended daily intake of protein, vitamin B2, potassium, magnesium, calcium, and phosphorus. The content of lactic acid and bifidobacteria remained above the norm (1×108) both in fresh products and by the end of their shelf life. Conclusion. The article introduces a technology of new functional soy-fortified fermented milk drinks with improved chemical and sensory properties.