Water-Dispersible Phytosterol Nanoparticles: Preparation, Characterization, and in vitro Digestion

For improving solubility and bioaccessibility of phytosterols (PS), phytosterol nanoparticles (PNPs) were prepared by emulsification–evaporation combined high-pressure homogenization method. The organic phase was formed with the dissolved PS and soybean lecithin (SL) in anhydrous ethanol, then mixed with soy protein isolate (SPI) solution, and homogenized into nanoparticles, followed by the evaporation of ethanol. The optimum fabrication conditions were determined as PS (1%, w/v): SL of 1:4, SPI content of 0.75% (w/v), and ethanol volume of 16 ml. PNPs were characterized to have average particle size 93.35 nm, polydispersity index (PDI) 0.179, zeta potential −29.3 mV, and encapsulation efficiency (EE) 97.3%. The impact of temperature, pH, and ionic strength on the stability of fabricated PNPs was determined. After 3-h in vitro digestion, the bioaccessibility of PS in nanoparticles reached 70.8%, significantly higher than the 18.2% of raw PS. Upon freeze-drying, the particle size of PNPs increased to 199.1 nm, resulting in a bimodal distribution. The solubility of PS in water could reach up to 2.122 mg/ml, ~155 times higher than that of raw PS. Therefore, this study contributes to the development of functional PS-food ingredients.

Investigation of Enzymatic Hydrolysis Kinetics of Soy Protein Isolate: Laboratory And Semi-Industrial Scale

Soy protein isolate is a worthy substitute for meat protein. However, its low level of digestibility limits its spread to new market niches. This problem can be solved by enzymatic hydrolysis of soy protein to peptides. Several research teams have already been solving this problem, but their results were obtained under laboratory conditions and do not provide information about the reproducibility of the results on an industrial scale. In this paper, we have compared the results of laboratory and semi-industrial experiments of enzymatic hydrolysis of protein. Also the kinetics of the reaction under different conditions is shown, and the final product is characterized. The obtained results of semi-industrial experiments can form the basis of industrial regulations for the production of soy protein hydrolysate as an easily digestible form of dietary protein for athletes and patients with digestive disorders.