| The research on microorganism and enzyme of flue-cured tobacco leaves during aging was conducted during 2000-2002. The results showed that:1. Phyllospheric microorganism existed on tobacco leaves. Endophytic bacteria in tobacco was firstly defined in this article. The quantity of phyllospheric microorganism and endophyric bacteria was large in fresh leaves, endophytic bacteria quantity was much larger than phyllospheric bacteria, the time was 1.86; After curing, microorganism quantity reduced quickly, phyllospheric bacteria reduced 99.97%, endophytic bacteria reduced 99.99%, mould reduced 99.02%. A large number of microorganism were died during redrying, then the microorganism quantity reduced in the beginning of aging; The contrast of phyllospheric bacteria and endophytic bacteria was 16:1, the microorganism quantity continue to reduce during aging, at the end of aging endophytic bacteria reduced 98.86% contrasting to the beginning of aging, endophytic bacteria reduced 81.36%, the contrast of phyllospheric bacteria and endophytic bacteria was 1:1, mould's quantity was 0.2. Phyllospheric microorganism's species and quantity were influenced by environment, endophytic bacteria influenced to tobacco leaves quality more directly and much larger than phyllospheric bacteria. Erwinieae, Plesiomonas, Aeromonas bacteria lived as endophytic bacteria during the first three period, these dominantbacteria led to important action in the chemical components degrading of sugar, starch , protein, pectin and the conversion from nitrate to nitrite, and this was the basic of aging. The dominant bacteria during aging was sporeformer which had high resistance. It was proved that microorganism participate in the process of aging at the beginning by the quantity of microorganism and the conversion of chemical components, then microorganism had little influence to the quantity of tobacco leaves after three months of aging. Mould had much little influence than bacteria to tobacco leaves quality during aging, actinomyce couldn't be separated during the whole process of aging.3. The experiment of microorganism separation and identification from different ecological region in our country proved that the effect of microorganism to the different tobacco characters of ecological region was not high.4. In mature fresh leaves, the activity of amylase and proteinase was high and invertase was low. Amylase and proteinase still had activity after curing and drying, their activity would be higher at three mouths of aging, and this activity would be the highest activity during aging. After three months of aging, enzyme activity continued to reduce. Neutral proteinase had no activity after redrying. Polyphenol oxidase had only little activity after curing, then its activity couldn't be tested after that. The content of starch, non-reducing sugar, soluble protein free ammo acid, chlorophyll kept reducing during aging. The content of carotenoid and petroleum ether extract reduced at three months of aging and then increased. The top content of nitrate and nitrite was at three months of aging, then they would continue to reduce.5. The enzyme activity and chemical components of cured leaves all changed after microwave treatment. The activity of invertase and amylase reduced. Soluble protein content first increased and than reduced, low power treatment had no clear effect toprotein, middle power and high power treatment could lead to the reducing of soluble protein content; Free amino acid content reduced only a little; Chlorophyll a and chlorophyll b content all reduced, carotenoid content had no clear change; Petroleum ether extract content increased. Compare to the tobacco leaves after aging which were treated by microwave and which were not treated by microwave, their chemical components were obviously different; Soluble protein content reduced, free amino acid content increased, nicotine content increased, chlorophy a content totally reduced, and chlorophyll b and carotenoid content had no obviously change.
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