Starch degradation by alpha-amylase in tobacco leaves during the curing process

Yamaguchi, Naoto; Suzuki, Shingo; Makino, Amane

doi:10.1080/00380768.2013.842884

Cited by 22 publications

(11 citation statements)

References 34 publications

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“…In order to achieve favorable physical and chemical properties, tobacco leaves are subjected to different processes, injury, and heat and osmotic stresses [42]. During the process of curing, which includes aging, yellowing, browning, drying, and fermentation, different chemical changes occur in controlled conditions of temperature, moisture content and ventilation.…”

Section: Changes During Processing Of Tobacco Leavesmentioning

confidence: 99%

“…Total carbohydrate content remains almost the same during processing, because starch content decreases while water-soluble sugar content increases (Figure 1). Sweet, roast smell appears as a result of curing [42]. On the other hand, aging is a mild fermentation process.…”

Section: Changes During Processing Of Tobacco Leavesmentioning

confidence: 99%

“…In the research of Abubakar et al [43], most of the starch degraded within the first 80 h of the yellowing phase. Yamaguchi et al [42] proved starch degradation in tobacco leaves during the curing process to be predominantly caused by α-amylase. Other reported enzymes involved in starch degradation are glucan water dikinase and β-amylase, but they are more important during growing, and less during leaf processing.…”

Section: Degradation Of Starchmentioning

confidence: 99%

“…Under normal growing conditions, starch degrades as follows. First, it is phosphorylated by glucan water dikinase, and then the phosphorylated soluble starch degradation is catalyzed by β-amylase and isoamylase, releasing considerable amounts of maltose [42]. At the same time, proteins are fragmented releasing amino acids, which will be lately contribute in Maillard reaction with sugars [6].…”

Section: Degradation Of Starchmentioning

confidence: 99%

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Carbohydrates—Key Players in Tobacco Aroma Formation and Quality Determination

et al. 2020

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Carbohydrates are important compounds in natural products where they primarily serve as a source of energy, but they have important secondary roles as precursors of aroma or bioactive compounds. They are present in fresh and dried (cured) tobacco leaves as well. The sugar content of tobacco depends on the tobacco variety, harvesting, and primarily on the curing conditions (temperature, time and moisture). If the process of curing employs high temperatures (flue-curing and sun-curing), final sugar content is high. In contrast, when air curing has a lower temperature, at the end of the process, sugar level is low. Beside simple sugars, other carbohydrates reported in tobacco are oligosaccharides, cellulose, starch, and pectin. Degradation of polysaccharides results in a higher yield of simple sugars, but at the same time reduces sugars oxidization and transfer into carbon dioxide and water. Loss of sugar producers will compensate with added sugars, to cover undesirable aroma properties and achieve a better, pleasant taste during smoking. However, tobacco carbohydrates can be precursors for many harmful compounds, including formaldehyde and 5-hydroxymethylfurfural. Keeping in mind that added sugars in tobacco production are unavoidable, it is important to understand all changes in carbohydrates from harvesting to consuming in order to achieve better product properties and avoid the formation of harmful compounds. This review summarizes current knowledge about tobacco carbohydrates, including changes during processing with special focus on carbohydrates as precursors of harmful compounds during smoking.

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Section: Changes During Processing Of Tobacco Leavesmentioning

confidence: 99%

Section: Changes During Processing Of Tobacco Leavesmentioning

confidence: 99%

Section: Degradation Of Starchmentioning

confidence: 99%

Section: Degradation Of Starchmentioning

confidence: 99%

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Carbohydrates—Key Players in Tobacco Aroma Formation and Quality Determination

et al. 2020

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“…The α-amylase isoform I-1 (AmyI-1) is a key enzyme in starch metabolism and it has been reported that AmyI-1 is involved in starch degradation in plastids [7,8]. Yamaguchi et al [9] showed a correlation between α-amylase and starch content in the leaf sheath after heading with the activity being consistent with the degree of starch degradation. AmyI-1 is also targeted to chloroplasts and plastids [7,8].…”

Section: Introductionmentioning

confidence: 99%

Functional Analysis of Rice Long-Chain Acyl-CoA Synthetase 9 (OsLACS9) in the Chloroplast Envelope Membrane

Kitajima-Koga

Baslam

Hamada

et al. 2020

IJMS

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The long-chain acyl-CoA synthetases (LACSs) are involved in lipid synthesis, fatty acid catabolism, and the transport of fatty acids between subcellular compartments. These enzymes catalyze the critical reaction of fatty acyl chains to fatty acyl-CoAs for the triacylglycerol biosynthesis used as carbon and energy reserves. In Arabidopsis, LACSs are encoded by a family of nine genes, with LACS9 being the only member located in the chloroplast envelope membrane. However, the comprehensive role of LACS9 and its contribution to plant metabolism have not been explored thoroughly. In this study, we report on the identification and characterization of LACS9 mutants in rice plants. Our results indicate that the loss-of-function mutations in OsLACS9 affect the architecture of internodes resulting in dwarf plants with large starch granules in the chloroplast, showing the suppression of starch degradation. Moreover, the plastid localization of α-amylase I-1 (AmyI-1)—a key enzyme involved in starch breakdown in plastids—was suppressed in the lacs9 mutant line. Immunological and confocal laser scanning microscopy analyses showed that OsLACS9-GFP is located in the chloroplast envelope in green tissue. Microscopic analysis showed that OsLACS9s interact with each other in the plastid envelope membrane. Furthermore, OsLACS9 is also one of the proteins transported to plastids without a transit peptide or involvement of the Toc/Tic complex system. To identify the plastid-targeting signal of OsLACS9, the transient expression and localization of a series of N-terminal truncated OsLACS9-green fluorescent protein (GFP) fusion proteins were examined. Truncation analyses identified the N-terminal 30 amino acid residues to be required for OsLACS9 plastid localization. Overall, the data in this study provide an advanced understanding of the function of OsLACS9 and its role in starch degradation and plant growth.

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Microbial community and metabolic function analysis of cigar tobacco leaves during fermentation

Liu

Zhu

et al. 2021

MicrobiologyOpen

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Cigar tobacco leaves (CTLs) contain abundant bacteria and fungi that are vital to leaf quality during fermentation. In this study, artificial fermentation was used for the fermentation of CTLs since it was more controllable and efficient than natural aging. The bacterial and fungal community structure and composition in unfermented and fermented CTLs were determined to understand the effects of microbes on the characteristics of CTLs during artificial fermentation. The relationship between the chemical contents and alterations in the microbial composition was evaluated, and the functions of bacteria and fungi in fermented CTLs were predicted to determine the possible metabolic pathways. After artificial fermentation, the bacterial and fungal community structure significantly changed in CTLs. The total nitrate and nicotine contents were most readily affected by the bacterial and fungal communities, respectively. FAPROTAX software predictions of the bacterial community revealed increases in functions related to compound transformation after fermentation. FUNGuild predictions of the fungal community revealed an increase in the content of saprotrophic fungi after fermentation. These data provide information regarding the artificial fermentation mechanism of CTLs and will inform safety and quality improvements.

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Starch degradation by alpha-amylase in tobacco leaves during the curing process

Cited by 22 publications

References 34 publications

Carbohydrates—Key Players in Tobacco Aroma Formation and Quality Determination

Carbohydrates—Key Players in Tobacco Aroma Formation and Quality Determination

Functional Analysis of Rice Long-Chain Acyl-CoA Synthetase 9 (OsLACS9) in the Chloroplast Envelope Membrane

Microbial community and metabolic function analysis of cigar tobacco leaves during fermentation

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