Impacts of thermal sterilization on volatile substances in xiongzhang tofu seasoning packets according to electronic nose and gas chromatography-mass spectrometry
Lian He, Yuwen Yi, Cheng‐Jian Xu, Jing Deng, Hua-Chang Wu, Mingfeng Qiao, Sook Wah Chan, Jin-Xiang Hu
Abstract
Seasoning packets, which are essential for pre-cooked Xiongzhang tofu dishes, contain odor substances that are crucial for providing food aromas because of their low molecular weights, boiling points, and volatilities. Identifying these volatile substances is crucial; however, the impact of sterilization on these compounds is not well understood. Therefore, we explored the effect of thermal sterilization on the volatile substance content of Xiongzhang tofu seasoning packets. Three different sterilization treatments were investigated using sensory evaluation, electronic noses, and gas chromatography-mass spectrometry (GC-MS) combined with microbial indicators, orthogonal partial least squares discriminant analysis, the odor activity value (OAV), and differential heat maps. Heat sterilization enhanced flavor richness and preference scores, with the microbial content meeting national standards. GC-MS analysis revealed that pasteurized samples had high similarity with non-sterilized samples, whereas high-temperature/high-pressure sterilized samples showed significant differences. OAV analysis revealed dominant fruity, floral, and spicy aromas, with significant differences in the characteristic compounds among samples. The main characteristic differences among the three treatments were attributed to compounds including (methoxymethyl) ethylene oxide, 2,3-butanediol, epoxypropane, methoxyacetone, methyl thioether, and formic acid. High-temperature/high-pressure sterilization may have facilitated the release of sulfur-containing substances. This study enriches our understanding of the impacts of thermal sterilization of the volatile substance content of seasoning packets in pre-cooked dishes. • Heat sterilization improves the overall flavor profile of seasoning packets. • Odoriferous compounds validate the reliability of electronic nose analysis. • The sample flavor post-heat sterilization was richer and fuller. • High temperature/high pressure sterilization can improve the release effect of sulfides in seasonings.