Effect of Electron Beam Irradiation Sterilization on Volatile Components of Zhaotong Soybean Paste

Abstract

This paper examined the effects of different doses of electron beam irradiation on the sensory evaluation, microbial content and changes in volatile components of Zhaotong soybean paste, aiming to investigate the feasibility of irradiation sterilization for Zhaotong soybean paste. According to the results, when the electron beam irradiation dose was 3.68 kGy, the comprehensive sensory evaluation of Zhaotong soybean paste was good, and the total number of bacteria, fungi and coliform contents met the health standards. A total of 41 volatile components were identified in Zhaotong soybean paste before irradiation and 100 volatile components were detected after irradiation. The volatile components after irradiation mainly consisted of 32 esters, 4 aldehydes, 26 alkenoids, 15 alcohols, 11 ketones, 1 ether, 2 phenols and 9 other substances. Among them, the irradiation dose had greater effects on alcohols, esters, aldehydes and other types of volatile substances. The types and contents of esters increased significantly after irradiation, while the contents of aldehydes and alkylenes decreased. The volatile components of Zhaotong soybean paste before irradiation were mainly isobutanol, linalool, 4,7-dimethyl undecane and methyl linoleate, accounting for 36.90%, 20.29%, 11.70% and 4.94% of the total content, respectively. On the other hand, the volatile components in irradiated Zhaotong paste were dominantly linalool, methyl linoleate, ethyl benzoate and Ligustrazine. The relative contents of isobutanol decreased significantly after irradiation while linalool remarkably increased. Based on the results, it could be concluded that 3.68 kGy was a reliable dose for the irradiation sterilization of Zhaotong soybean paste, and the results would provide reference information for the promotion of Zhaotong soybean paste to the highland local specialties.

Keywords

• zhaotong soybean paste
• electron beam irradiation
• volatile ingredients
• headspace solid phase micro extractions
• gas chromatgraphy mass spectrometry