Mechanism and Regulation of Tea Saponin Extraction from C. oleifera Seed Meal in Subcritical Water

Tea saponins are excellent natural surfactants, and previous studies on their extraction from <i>C. oleifera</i> seed meals in subcritical water have mainly focused on the optimization of external extraction conditions. In order to achieve the efficient extraction of tea saponins in subcritical water, this study explores the influence of the composition-internal factors on the extraction rate of tea saponins. In this study, the composition of three <i>C. oleifera</i> seed meals purchased from Hubei, Hunan and Guizhou province and extraction rates of tea saponins, dissolution rates of reducing sugars and proteins from these <i>C. oleifera</i> seed meals were compared, and the results showed that reducing sugars and proteins were intrinsic components affecting extraction rates of tea saponins in subcritical water. The simulation system involving tea saponins, whey protein isolate (WPI), and glucose in subcritical water showed that WPI reduced the content of tea saponins through the Maillard reaction, and glucose inhibited the participation of tea saponins in the Maillard reaction. The above mechanism was verified using alkaline protease, which changed the content of reducing sugars and proteins in the <i>C. oleifera</i> seed meal purchased from Hubei province, and provided guidance for achieving the efficient extraction of tea saponins.