原烟复烤前后细菌种群变化研究

Study on Change of Bacteria Populations of Raw Tobacco Leaves before and after Redrying

为明确原烟复烤前后表面细菌种群变化情况及其对烟叶发酵的影响,考察了3种不同烟叶(自然状态下的原烟、施加微生物的原烟、复烤后片烟)经发酵后微生物及化学成分的变化情况。不同烟叶发酵1个月后,利用变性梯度凝胶电泳(DGGE)方法研究表面细菌的变化情况,并采用连续流动分析法检测化学成分的变化规律。结果表明:与原烟相比,复烤后烟叶表面的细菌发生明显变化,其中降解蛋白质菌(Bacillus cereus)、降解淀粉菌(Bacillus amyloliquefaciens、Bacillus subtilis)、产香菌(Erwinia、Pantoeadispersa)等细菌的数量均明显低于复烤前的原烟。发酵后,原烟表面富集上述几类细菌,而复烤后烟叶表面细菌则未得到明显富集,部分细菌已检测不到。烟叶发酵1个月后,淀粉、蛋白质、氮含量均降低,还原糖含量显著增加,且原烟的化学成分变化幅度显著高于复烤后烟叶。表明复烤工艺可造成烟叶表面细菌种类和数量减少,由此影响烟叶发酵过程。

In order to study the changing of bacterial populations on the leaf surface of tobacco before and after redrying, three different kinds of tobacco leaves were investigated, including raw tobacco leaves, raw tobacco leaves adding microbes and flue-cured tobacco leaves. After fermentation for one month, the change of bacterial populations on the leaf surface of tobacco were studied by DGGE （ denaturing gel gra-dient electrophoresis） ,the change of chemical compositions of tobacco leaves were detected by the contin-uous flow method. The results showed that the bacterial populations on the leaf surface of tobacco changed largely after redrying. The numbers of protein degrading bacteria （ Bacillus cereus） , starch degrading bacte-ria （Bacillus amyloliquefaciens , Bacillus subtilis） and aroma producing bacteria^ Erwinia ,Pantoeadispersa） were obviously lowered after redrying. These kinds of bacteria were increased in raw tobacco leaves after one month fermentation, while they almost disappeared in the flue-cured tobacco leaves. For chemical compositions ,contents of starch ,protein and total nitrogen declined , sugar content increased. Likewise, the change amplitude of these chemical compositions was relatively larger in raw tobacco leaves than that in the flue-cured tobacco leaves. Study here indicated that the redrying process could reduce the bacterial population on the surface of tobacco leaves,which may effect the fermentation process.