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.