Process Technology of Improving the Quality of Sun-cured Red Tobacco Leaves by Co-fermentation of Cellulose-degrading Bacteria and Cocoa Powder

Purpose To reduce the cellulose content in sun-cured red tobacco leaves, decrease the irritancy of the leaves, and improve overall quality.

Methods Bacteria capable of degrading cellulose were isolated from the surface of sun-cured red tobacco leaves. The strain with the highest cellulase production was used for enzyme fermentation. The enzyme solution produced by fermentation of the strain and cocoa powder were used to treat sun-cured red tobacco leaves, and the optimum fermentation process parameters were determined according to the degradation rate of cellulose.

Results Six strains capable of degrading cellulose were isolated from the surface of sun-cured red tobacco leaves, and the strain HNY63 showed the highest cellulase production. The enzyme solution produced by fermentation of strain HNY63 was diluted to a cellulase activity of 12.92 U/mL, and the cocoa powder and diluted enzyme solution were added at 0.5% and 25.0% of the weight of tobacco leaves, respectively. After fermentation at 45 ℃ for 48 hours, the degradation rate of cellulose in sun-cured tobacco leaves reached 26.90%. Additionally, the chemical composition of the leaves was optimized, increasing the content of aromatic compounds significantly. The aroma characteristics were enhanced, and the offensive taste and irritancy were reduced, greatly improving the overall quality of the tobacco leaves.

Conclusion The fermentation treatment using the enzyme solution from strain HNY63 in combination with cocoa powder is an efficient process for improving the quality and aroma characteristics of sun-cured red tobacco leaves.