Emulsions stabilized by soy protein nanoparticles as potential functional non-dairy yogurts.

BACKGROUND: Rice bran oil and soy protein nanoparticles (SPNs) may be considered as novel functional food ingredients for soy yogurt production. Formulation of soy yogurt with SPNs and rice bran oil, which has significant physiological functions, will convert them into functional food products. This study was conducted to develop rice bran oil-based soy protein nanoparticles emulsion (SPNE) and to evaluate physical properties, antioxidant activities, oxidative stability and microbiological load as well as textural attributes of SPNs incorporated yogurt (SPNY) during storage at 4 °C for 45 days. RESULTS: SPNs were prepared from soy protein isolate of defatted soy flour. Solubilization, crystallization and ultrasonication was carried out six times. After the sixth cycle of repeated solubilizing, crystallization and ultrasonication, the size of nano protein was reduced to 72.42 ± 0.22 nm from 586.72 ± 0.75 nm (after first cycle). Viscosity, penetration values and water-holding capacity of SPNs added to yogurt were decreased with increase in reduction size of SPNs. SPNs added to yogurt exhibited greater antiradical scavenging ability and ferric reducing antioxidant property than control yogurt. Fortified soy yogurt had significant higher oxidative stability and proteolytic activity. CONCLUSION: Fortification of non-dairy food products with SPNs, which has significant physiological functions, convert conventional soy yogurt into functional food products. © 2019 Society of Chemical Industry.

Hepatoprotective effects of synbiotic soy yogurt on mice fed a high-cholesterol diet.

OBJECTIVES: The role of probiotic yogurt in the prevention and treatment of hypercholesterolemia has attracted global attention. Mounting evidence has indicated that probiotics and prebiotics improve lipid metabolism by lowering low-density lipoprotein cholesterol concentration in plasma of hypercholesterolemic patients. The present study aimed to develop synbiotic soy yogurt that had a greater cholesterol-lowering effect in hypercholesterolemic mice compared with control soy yogurt. METHODS: Synbiotic soy yogurt was prepared using soy milk and synbiotic capsule containing LactoBacil Plus (SCLBP) probiotic cultures and fructo-oligosaccharide. Synbiotic soy yogurt was analyzed for proximate composition and microbiological and antioxidative properties during storage periods of 28 d. To study hypocholesterolemic effect, hypercholesterolemia was induced in mice with administration of 1.25% cholesterol and 0.5% cholic acid for 4 wk. After that 24 male Balb/c mice were randomly divided into four groups and fed basic, high-cholesterol, high-cholesterol with soy yogurt, or high-cholesterol with synbiotic soy yogurt diet for 5 wk. Blood samples were collected to measure lipids concentration and oxidative and antioxidative status. RESULTS: Proximate composition of SCLBP-formulated soy yogurt exhibits a marked difference from control soy yogurt in terms of total solids, moisture, protein, fat, ash, carbohydrate, and energy content. Results indicated that the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (75.28%) in synbiotic yogurt containing 2% SCLBP was significantly greater (P ≤ 0.05) compared with control soy yogurt (52.98%). In mice with hypercholesterolemia that were fed synbiotic soy yogurts, the yogurts had a favorable effect in reducing blood cholesterol, triglycerides, and low-density lipoprotein cholesterol and lipid peroxidation in liver. These led to a significant decrease of the atherogenic index compared with soy yogurt (control) only. Treatment with synbiotic soy yogurt cultures ameliorates lipid peroxidation in liver. CONCLUSIONS: These results indicated that the synbiotic soy yogurts have beneficial effects against hypercholesteroemia and can be used as a therapeutic agent in hypercholesteremic patients.