The impact of gradient variable temperature fermentation on the quality of cigar tobacco leaves

[El Presidente]

 

 

 

The impact of gradient variable temperature fermentation on the quality of cigar tobacco leaves

 

ORIGINAL RESEARCH article

Front. Microbiol.

Sec. Microbe and Virus Interactions with Plants

 

 

1 China Tobacco Sichuan Industrial Co., Ltd., Chengdu, Sichuan, China

2 China National Tobacco Quality Supervision & Test Centre, Zhengzhou, Henan Province, China

 

 

In order to enhance the quality of cigar tobacco leaves (CTLs), a gradient variable temperature fermentation approach was employed. Methods: The temperature gradient demonstrated a gradual increase from low temperature (35±2℃) to moderate temperature (45±2℃), and then to high temperature (55±2℃). Each temperature gradient underwent a 10-day fermentation process, resulting in a total duration of 30 days. Changes in sensory evaluation, chemical composition, and bacterial absolute quantitative structure and function were examined throughout the process of gradient variable temperature fermentation. Results: Compared to constant temperature fermentation, gradient variable temperature fermentation improved the sensory quality of CTLs, reduced total sugar and cembrane degradation products, and increased the amino acid contents. It resulted in significant changes in bacterial quantity and function of CTLs. The results of correlation analyses showed that sensory quality had significant correlation with chemical composition, which effected by predominant microbes. The gradient variable temperature fermentation process underwent a three-phase model to characterize the alterations of CTLs. Phase I (35℃) was the microbial stage, during which there was a significant decrease in both the total number and function of microorganisms. The dominant genera shifted from Acinetobacter to Staphylococcus and Corynebacterium, and with high reducing sugar, polyphenol compound and low sensory score. Phase II (45℃) marked a chemical stage, with an enhancement in sensory evaluation. A total of 17 chemicals significantly decreased and six increased, and the decline of microbial populations persisted. The enhanced relative abundances of four microecological hubs, had the potential to produce protease and lipase to the production of peptides, amino acids, and organic acid, catabolizing sugars and polyphenol compounds, through carbohydrate metabolism and amino acid metabolism, resulted an increase in sensory quality of CTLs. Phase III (55℃) indicated a relative mature stage with the highest score of sensory evaluation. Eight compositions from plamochromic pigments and polyphenol compounds exhibited gradual decreases, while relative contents of carbohydrate metabolism and amino acid metabolism increased. Conclusion: The gradient variable temperature fermentation had demonstrated a significant positive influence on the quality of CTL by providing optimal fermentation temperature for microbial growth, metabolism, and the generation of quality related chemical compositions.

Keywords: Cigar tobacco leaf (CTL), gradient variable temperature fermentation, bacterial community, Chemical component, Correlation analysis

Received: 16 May 2024; Accepted: 20 Nov 2024.

https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1433656/abstract

[MrBirdman]

I wonder how they maintained such precise temperature ranges? I also have zero clue how this compares to traditional Cuban or NC fermentation temps. I’m sure there are members here who can shed some light on that.