Effect of vacuum frying on the structure and bioactivity of proanthocyanidins in Chinese quince (Chaenomeles sinensis Koehne) fruit.

The consumption of Chinese quince is hindered by the lack of suitable processing method. Vacuum-frying technology, as an efficient processing method, can help address this issue. However, the effect of vacuum frying on the structure and activity of bioactive components in Chinese quince, such as proanthocyanidins, is currently unknown. In this study, Chinese quince was vacuum fried at 70 °C-100 °C. Proanthocyanidins were extracted, characterized, and analyzed for their bioactivity. Results revealed that increasing the vacuum-frying temperature decreased the total proanthocyanidin content. Vacuum frying reduced samples' degrees of polymerization. Proanthocyanidin extracts vacuum fried at 70 °C exhibited the greatest antioxidant capacity. Proanthocyanidin extracts vacuum fried at 80 °C demonstrated pronounced hypoglycemic potential. These results show that vacuum frying can reduce the degree of polymerization of Chinese quince proanthocyanidins while enhancing their antioxidant activity and retaining their hypoglycemic capacity. This study offers valuable insights for the development of functional foods using Chinese quince.