Recently, the research team of Fengzhong Wang, the innovation team for food nutrition and functional component utilization, performed headspace-gas chromatography ion mobility spectrometry (HS-GC-IMS) combined with 16SrRNA sequencing methods to clarify the discrepancy in characteristic flavor and bacteria composition of 10 fresh fermented rice noodles from southern China. The relevant research results were published in the journal Food Research International (IF: 6.475).

Fresh fermented rice noodle, as a staple food with springy bite and specific flavor, is widely produced and consumed in many Southeast Asian countries and south of China. There are diverse kinds of fresh fermented rice noodles with local characteristics in the south of China, such as Changde rice noodle, Yunnan Bridge rice noodle and Guilin rice noodle, which are well-known as regional specialty. Here, this paper makes it clear that the key volatile compounds and the core bacteria which contributed to the specific flavor of 10 fresh fermented rice noodles from the south of China.

Fig.2 Fingerprints of the different volatile components of the main volatile compounds (ROAV＞1)

Fig. 4 The bacterial composition of the 10 fresh fermented rice noodles. (A) Principal component analysis (PCA) of bacterial community on the OTU level; (B) Relative abundance of bacterial community at the genus level; (C) Relative abundance of bacterial community on the family level; (D) Taxonomic cladogram obtained from the LEfSe analysis of the 16S rRNA sequencing.

 

A total of 54 compounds were detected from 10 fresh fermented rice noodles. 1-Octen-one, ethyl 3-methylbutanoate, 3-methylbutanal, n-nonanal and hexanal were the key volatiles among them. The bacterial analysis showed that Leuconostoc and Lactococcus were the core bacteria at the genu level of all samples. Amyl acetate, 2-butanone and methyl-2-methylpropanoate were positively related to Lactococcus while ethanol was negatively correlated with Lactococcus. And Leuconostoc was positively related to 3-methylbutanal and acetone, while was negatively correlated with hexanal. Results indicated that key volatiles of different fresh fermented rice noodle samples were associated with bacterial composition.

This study elucidated the discrepancy in flavor of the 10 fresh fermented rice noodles from the south of China. These differences were closely associated with bacteria, which provided the guidance for developing the strain culture and standardizing the producing process of fresh fermented rice noodles.

 

Master student Aixia Wang is the first author, researcher Fengzhong Wang and Litao Tong as co-corresponding authors. This research was supported by the National Natural Science Foundation of China (31972005) and the Science and Technology Innovation Project of Chinese Academy of Agricultural Sciences (31401505).

 

Link to the paper: https://doi.org/10.1016/j.foodres.2021.110787