Yunnan Herbal Laboratory, School of Ecology and Environmental Science, Yunnan University, Kunming, Yunnan, 650091, P. R. China.
College of Basic Medicine, Yunnan University of Chinese Medicine, Kunming, Yunnan, 650500, P. R. China.
J Microbiol. 2021 Jan;59(1):20-28. doi: 10.1007/s12275-021-0219-4. Epub 2020 Dec 23.
The microbial community is one of the most important factors in shaping the characteristics of fermented food. Nuodeng ham, traditionally produced and subjected to 1-4 years of fermentation, is a dry fermented food product with cultural and economic significance to locals in southwestern China. In this study, we aimed to characterize the microbiota and physicochemical profiles of Nuodeng ham across different stages of fermentation. Ham samples from each of the four years were analyzed by sequencing bacterial 16S rRNA gene and fungal internal transcribed spacer sequence, in order to characterize the diversity and composition of their microflora. A total of 2,679,483 bacterial and 2,983,234 fungal sequences of high quality were obtained and assigned to 514 and 57 genera, respectively. Among these microbes, Staphylococcus and Candida were the most abundant genera observed in the ham samples, though samples from different years showed differences in their microbial abundance. Results of physicochemical properties (pH, water, amino acid, NaCl, nitrate and nitrite contents, and the composition of volatile compounds) revealed differences among the ham samples in the composition of volatile compounds, especially in the third year samples, in which no nitrite was detected. These results suggest that the structure and diversity of microbial communities significantly differed across different stages of fermentation. Moreover, the third year hams exhibits a unique and balanced microbial community, which might contribute to the special flavor in the green and safe food products. Thus, our study lends insights into the production of high quality Nuodeng ham.
微生物群落是塑造发酵食品特征的最重要因素之一。诺邓火腿是一种传统的干式发酵食品，经过 1-4 年的发酵，对于中国西南地区的当地人来说具有文化和经济意义。在这项研究中，我们旨在描述不同发酵阶段的诺邓火腿的微生物群和理化特性。对来自四年的火腿样本进行了细菌 16S rRNA 基因和真菌内部转录间隔区序列的测序分析，以描述其微生物菌群的多样性和组成。共获得了 2679483 条高质量的细菌序列和 2983234 条高质量的真菌序列，分别归为 514 个和 57 个属。在这些微生物中，葡萄球菌和假丝酵母是火腿样本中最丰富的属，但不同年份的样本在微生物丰度上存在差异。理化特性（pH 值、水分、氨基酸、NaCl、硝酸盐和亚硝酸盐含量以及挥发性化合物组成）的结果表明，不同年份的火腿样本在挥发性化合物的组成上存在差异，特别是在第三年的样本中，未检测到亚硝酸盐。这些结果表明，微生物群落的结构和多样性在不同发酵阶段有显著差异。此外，第三年的火腿表现出独特而平衡的微生物群落，这可能有助于绿色安全食品的特殊风味。因此，我们的研究为高质量的诺邓火腿生产提供了新的见解。
