Study on stability and in vitro digestion of camellia oil nanoemulsion system

The soy protein isolate (SPI) was combined with tea saponin as an emulsifier to prepare camellia oil nanoemulsion, and the stability of camellia oil nanoemulsion was compared with that of soybean protein isolate or tea saponin as emulsifier. The effects of different pH, ionic strength, heating temperature and storage time on the average particle size, ξ-potential and microstructure of camellia oil nanoemulsion prepared by three emulsifiers were studied. The results showed that the nanoemulsions prepared by combining natural emulsifiers (SPI-TS) in the pH range of 5-9 were stable and remained stable in the range of 0-300mm NaCl concentration, but had poor tolerance to high salt environment. After heating at different temperatures (30 °C-90 °C) for 30min, the average particle size, ξ-potential and microstructure of the three emulsions did not change significantly, showing good heating stability. At different storage temperatures (4, 25, 50°C) SPI-TS and TS emulsion could exist stably about four weeks, and had good storage stability. In addition, we performed in vitro simulated gastrointestinal digestion studies on the digestive properties of camellia oil nanoemulsions. The results showed that the particle size, the ξ-potential of the nanoemulsion changes depend on the type of emulsifier during digestion. The release rate of free fat acids (FFAs) of nanoemulsions after gastrointestinal digestion were all higher than that of the control group. The results showed that the nanoemulsion delivery system could effectively improve the digestion of camellia oil, It was important to improve the bioavailability of camellia oil.