Investigation of the degradation patterns and mechanisms of amide compounds in Zanthoxylum oil under temperature influence

Zanthoxylum oil, which is prepared by diluting CO₂ supercritical extracts with soybean oil, contains volatile oils and amide compounds. During storage, light, acidity, and temperature are the main factors causing the decrease in pungent components. The temperature-induced degradation mechanisms of these compounds remain ambiguous, which is challenging, because thermal effects significantly decrease product quality and sensory acceptability. In this study, the effect of temperature on pungent amides in Zanthoxylum oil was investigated, with a focus on characteristic spectra, degradation kinetics, and mechanistic analysis, to elucidate thermal degradation patterns and molecular mechanisms. The results indicate that hydroxy-α-sanshool, the principal amide, undergoes notable thermal degradation, with its degradation increasing proportionally with temperature. High-temperature treatments induce the isomerization of hydroxy-α-sanshool into hydroxy-β-sanshool and hydroxy-ε-sanshool, as well as oxidative transformation into compounds such as (2 E ,6 Z ,10 E )-8,9-dihydroxy-N-(2-hydroxy-2-methylpropyl)dodeca-2,6,10-trienamide and (2E,6Z,8E)-10,11-dihydroxy-N-(2-hydroxy-2-methylpropyl)dodeca-2,6,8-trienamide. These findings provide a scientific basis for optimizing processing strategies to mitigate degradation and increase the shelf life of Zanthoxylum -derived products. • Storage optimized, stability elucidated for Zanthoxylum extract. • The simulation clarified the degradation kinetics of HαSS, predicted its shelf life. • LC-MS/NMR analysis of HαSS degradation: pathways and thermal stability.