College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China; Key Laboratory of Leather Chemistry and Engineering, Ministry of Education, Sichuan University, Chengdu 610065, China.
Zigong Yanweiyuan Food Co. Ltd, Zigong 643010, China.
Food Res Int. 2022 Oct;160:111622. doi: 10.1016/j.foodres.2022.111622. Epub 2022 Jul 8.
Paocai is a traditional Chinese fermented vegetable product popular in Asian countries. As an important additive, salt concentration is closely related to the quality of paocai. The aim of this study was to investigate the effect of salt concentration on the physicochemical characteristics, microbial diversity, and flavor profiles of spontaneously fermented radish, and the cross-correlation between microorganisms and flavor compounds was also revealed. Analysis of the microbial diversity of paocai showed that Firmicutes, Proteobacteria, and Ascomycota were detected as the main phyla with different salt concentrations, Weissella and Lactobacillus were the predominant bacterial genera, and Yarrowia dominated the fungal genera. Based on LEfSe analysis, Lactobacillus, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Microbacterium, Lactococcus, Staphylococcus, and Weissella were regarded as differential genera caused by differences in salinity. Analysis of the flavor compounds showed that 17 free amino acids, 5 isothiocyanates, 3 terpenes, 15 sulphur-containing compounds, 16 esters, 8 organic acids, 9 aldehydes, 8 ketones, 25 alcohols, 7 nitriles, 2 lactones, and 10 hydrocarbons were detected. Then, the correlation between the microbial community and flavor compounds was revealed, and the results indicated that several bacterial genera significantly correlated with flavors, including Lactobacillus, Kosakonia, Weissella, Leuconostoc, and Staphylococcus, while fungi had weak correlations with flavors. In addition, Metacyc pathway analysis was carried out to elucidate the effect of salt content on the metabolic pathways, showing that most flavor-related pathways were up-regulated with the increase in salt content. Results presented in this study may contribute to further understanding the role of salt in the fermentation of paocai and provide effective references for quality control of traditional fermented vegetables.
泡酸菜是一种流行于亚洲国家的传统中国发酵蔬菜产品。盐浓度作为一个重要的添加剂，与泡酸菜的质量密切相关。本研究旨在研究盐浓度对自然发酵萝卜的理化特性、微生物多样性和风味特征的影响，并揭示微生物和风味化合物之间的交叉相关性。泡酸菜微生物多样性分析表明，不同盐浓度下检测到厚壁菌门、变形菌门和子囊菌门为主要门，魏斯氏菌属和乳杆菌属为主要细菌属，假丝酵母属占主导地位。基于 LEfSe 分析，认为盐度差异引起的差异属有乳杆菌属、根瘤菌属-类根瘤菌属-副根瘤菌属-根瘤菌属、微杆菌属、乳球菌属、葡萄球菌属和魏斯氏菌属。风味化合物分析表明，检测到 17 种游离氨基酸、5 种异硫氰酸酯、3 种萜烯、15 种含硫化合物、16 种酯类、8 种有机酸、9 种醛类、8 种酮类、25 种醇类、7 种腈类、2 种内酯类和 10 种烃类。然后，揭示了微生物群落与风味化合物之间的相关性，结果表明，几个细菌属与风味有显著相关性，包括乳杆菌属、约氏乳杆菌属、魏斯氏菌属、肠膜明串珠菌属和葡萄球菌属，而真菌与风味相关性较弱。此外，进行了 Metacyc 途径分析，以阐明盐含量对代谢途径的影响，结果表明，随着盐含量的增加，大多数与风味相关的途径都上调。本研究结果可能有助于进一步了解盐在泡酸菜发酵中的作用，并为传统发酵蔬菜的质量控制提供有效参考。
