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

Abstract

BACKGROUND Rice bran oil and soy protein nanoparticles (SPN) may be considered as novel functional food ingredients for soy yogurt production. Formulation of soy yogurt with soy protein nanoparticles 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 SPN incorporated yogurt (SPNY) during storage at 4°C for 45 days. RESULTS SPN were prepared from soy protein isolate of defatted soy flour. Solubilization, crystallization and ultrasonication had been carried out for 6 times. After 6th cycle of repeated solubilizing, crystallization and ultrasonication, 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 SPN added yogurt were decreased with increase in reduction size of SPNs. SPN added yogurt exhibited greater antiradical scavenging ability and ferric reducing antioxidant property than control yogurt. Fortified soyyogurt had significant higher oxidative stability and proteolytic activity. CONCLUSION Fortification of non-dairy food product with SPN, which has significant physiological functions convert conventional soy yogurt into functional food products.