Dynamic variation and interrelation in the volatile and non-volatile fractions of deep-fried green onion (Allium fistulosum L.) oil with different frying temperatures

The flavor of deep-fried green onion oil (FO) changed significantly at 155 °C, with decreased fresh onion-like aroma and green scent, and increased savory and burnt notes. A total of 144 odorants were identified in FO samples. The total content of sulfur-containing odorants was highest at 155 ℃, while the total content of target furans and aldehydes/ketones peaked at 165 ℃. UFA accounted for approximately 95% of the non-volatile fractions in FO, mainly in the form of PUFA. The oxidation degradation of UFA at high temperatures promoted the generation of small molecule aldehydes. Odorants in FO predominantly originated from reactions between sugars and amino acids, contributing to the enticing aroma.