PJB-2024-1539
Growth characteristics of aroma-enhancing bacteria in reconstituted tobacco extracts using isothermal microcalorimetry
Shen Huang, Lanxin Zhang, Mingyi Yan, Jinchu Yang, Aamir Rasool, Robina Manzoor, Tingting Zhang, Yingjie Feng and Duobin Mao
Abstract
Microorganisms, particularly those contributing to aroma development, play a vital role in the aging of flue-cured tobacco. In this study, heat release by five aroma-enhancing bacteria were measured during their growth in reconstituted tobacco extracts using isothermal microcalorimetry (IMC). The growth of the strains H4 (Pantoea), H8 (Klebsiella), H9 (Acinetobacter), H11 (Staphylococcus), and H12(Enterobacter) was detected under the conditions of 3%(v/v) inoculations, temperature of 26, 30, 34 and 37℃, pH 6 and 2.6 baume degree. Additionally, the growth of H8 was analyzed under the conditions of 30℃, pH of 4, 5, 6, 7, 8, baume degrees of 2.6, 5.2, 10.4, 15.6, 20.8 and 26. The number and contents of aroma components in reconstituted tobacco extracts significantly increased compared to the control groups after fermentation by H8, with resulting in significant enhancement of aroma. Specifically, the total content of aroma components in the reconstituted tobacco extracts was 9.245 mg/mL. Further, important aroma components significantly increased compared to controls, with 4,7,9-megastigmatrien-3-one increasing by 0.43 mg/mL, (Z)-6,10-Dimethyl-5, 9-undecadien-2-one by 0.144 mg/mL, (E)-6,10-Dimethylundeca-5, 9-dien-2-one by 0.072 mg/mL, (E)-5-isopropyl-8-methylnona-6,8-dien-2-one by 0.059 mg/mL, and (2, 6, 6-Trimethyl-2-hydroxycyclohexylidene) acetic acid lactone by 0.044 mg/mL. The content of Benzyl alcohol changed the most, increased by 943.86%, Benzaldehyde increased by 93.75%, and (E)-5-isopropyl-8-methylnona-6,8-dien-2-one increased by 84.29%. These findings lay the groundwork for optimizing aroma enhancement through H8 and comprehending the underlying mechanisms. Furthermore, they serve as a foundation for optimizing microbial growth characteristics within opaque reconstituted tobacco extracts
To Cite this article:
Huang, S., L. Zhang, M. Yan, J. Yang, A. Rasool, R. Manzoor, T. Zhang, Y. Feng and D. Mao. 2024. Growth characteristics of aroma-enhancing bacteria in reconstituted tobacco extracts using isothermal microcalorimetry. Pak. J. Bot., 56(4): DOI: http://dx.doi.org/10.30848/PJB2024-4(27)
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