The physicochemical properties and gastrointestinal fate of oleosomes from non-heated and heated soymilk

摘要

Soymilk is a widely consumed food rich in lipids and proteins. The lipids are stored in a subcellular organelle known as oleosomes (oil bodies). Conventionally, soymilk is consumed after heating to reduce the intensity of beany flavor, however little information is available regarding the potential impact of heating on the physicochemical and gastrointestinal fate of oleosomes. In this study, oleosomes isolated from heated and non-heated soymilk were used to investigate the effects of thermal treatment on their physicochemical properties and digestive fate, using a simulated gastrointestinal tract model. The thermal treatment caused compositional changes in the surface proteins of oleosomes, as depicted in the SDS-PAGE results. Heating led to an increase in the particle size, and has no significant on the zeta-potential of oleosomes. On the other hand, non-heated oleosomes were much more viscoelastic. In addition, non-heated oleosomes have a slightly slower free fatty acid (FFA) release rate during digestion. After digestion, the antioxidant capacity of the digesta of the heated oleosomes was slightly stronger. This was likely due to the release of small peptides at the end of digestion. Importantly, four bioactive peptides were identified in the non-heated oleosome digesta, with three more in the heated oleosome digesta.