The stir-frying process of Citrus reticulata ‘Chachi’: Process optimization, physical and chemical properties, and spectrum-activity relationship

To optimize the stir-frying process of Citrus reticulata ‘Chachi’ (CRC), analyze the physical and chemical properties and evaluate the activity. The best process condition was stir-frying temperature 110 ± 10 °C and time 25 min. The stir-frying Citrus reticulata ‘Chachi’ (SCRC) induced notable changes in the appearance and microstructure, enhancing its aroma and mellowness, reducing water content, and no aflatoxin was detected. It increased total flavonoids content. The ultra-high performance liquid chromatography fingerprints of SCRC and CRC showed 11 common peaks, seven compounds were identified by the retention time with the peak shapes of the Ultraviolet spectra. Through ABTS radical scavenging and α-glucosidase activity inhibition experiment, it was found that SCRC had stronger activity. The results of grey correlation analysis showed that peak 11 (tangeretin) was closely related to antioxidant activity, and peak 9 (nobiletin) was closely related to hypoglycemic activity. The analysis revealed that the components of antioxidant and hypoglycemic effects both overlapped and differed, suggesting a correlation between the two. The stir-frying process improved the product quality and activities and was conducive to its application and industrialization for simplicity and practicality, thus providing a scientific basis for natural plants to industrial products with the process technology.