Characterization and Evaluation of Changes in the Aroma-Active Components in Szechuan Pepper (Zanthoxylum bungeanum Maxim) Under Different Cooking Temperatures Using Gas Chromatography-Olfactometry

Abstract

The flavor of Szechuan pepper plays an important role in Sichuan cuisine, where it is responsible for the tingling and numbing characteristic. The aims of this study were to characterize and identify aroma-active compounds of Szechuan pepper and to evaluate changes in flavor components between room and high temperature (ca. 70–80 °C). Solvent-assisted flavor evaporation (SAFE) and headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O) were used. In this study, linalool, linalyl acetate, and limonene were identified as the major components by both SAFE and HS-SPME. Seven compounds, namely myrcene, limonene, 1,8-cineole, linalool, 2-phenylethanol, 4-methylacetophenone, and trans-carveol, were identified as aroma-active compounds using GC-O. The most intense aroma-active compounds were 1,8-cineole and linalool. Moreover, 2-phenylethanol and 4-methylacetophenone were identified as aroma-active components for the first time in Szechuan pepper. The relative contents of 1,8-cineole, linalool, 2-phenylethanol, 4-methylacetophenone, and trans-carveol were significantly increased as simulated cooking temperature increased from 40 to 75 °C, whereas myrcene, limonene, and hexanal were significantly decreased; 1,8-cineole was not detected at 40 °C but was detected at 75 °C. A total of 83 volatile compounds were identified, including 62 by SAFE and 57 by HS-SPME. Of these, 34 volatile compounds were identified by both SAFE and HS-SPME. For the first time, 2-phenylethanol and 4-methylacetophenone were identified as key aroma-active components in Szechuan pepper. The overall flavor of Szechuan pepper might be influenced by a result of the relative ratios of key aroma-active components. Cooking temperature should be taken into consideration when Szechuan pepper is used as an ingredient in food. These results could be beneficial for furthering our understanding of aroma-active compounds in Szechuan pepper and improving dishes prepared with this ingredient.