| The aging time and quality of tobacco strips was directly related to the usability of cigarette raw material and economic profits of charity.So far,it is a focus of attention and urgent problem of every cigarette charity and scientific workers of tobacco to promote the aging quality of tobacco strips,lower the storing cost,increase the usability of tobacco raw material.Modern instrumental analysis and statistics methods were used in this research with material from different storing conditions,producing areas and grades,and systematically analyzed the changing rules of moisture content,p H value,some carbohydrate,nitrogen-containing components,fragrant precursor,volatile aroma and some readily oxidizable substance of tobacco strips during aging.Meanwhile,the diversity of types and growth of endophytic bacteria in tobacco strips of different producing areas was investigated by plate method,16 SrDNA series analysis methods and cluster analysis methods,etc.and analyzed the enzyme activity differences of degrading enzyme and oxidase by endophytic bacteria.Results are as follows:1.Effects of different storing environments on moisture content and pH of tobacco strips were studied in this research.Results showed that the natural environment have large impact on environmental temperature and humidity of tobacco mellowing storage,while storing temperature and humidity have large impact on relative moisture and pH value of tobacco strips.The different aroma type of tobacco strips in 3 mellowing storage with relative moisture content variation range have significant difference(P<0.05),relative moisture content variation range in strong flavor type and clean flavor type of tobacco in different storage area significantly greater than relative moisture content variation range in local production and storage.During aging,the different aroma type of tobacco strips in 3 mellowing storage with pH value continued to decline,showed that alkaline material is reducing and acid material is increasing after aging,the Xingyi with high humidity and high temperature mellowing storage of clean flavor type and middle flavor type tobacco strips with pH value declined more than the Guiyang mellowing storage and Guiding mellowing storage of tobacco strips,but strong flavor type tobacco strips in 3 mellowing storage with pH value decline showed no significant difference.2.Effects of different storing conditions on soluble sugar and alkaloid of tobacco strips were studied in this research.Results showed that in the aging process of tobacco strips,the content of the total sugar and reducing sugar in different aroma types of tobacco strips of three mellowing storage showed a trend of decline,and the fastest rate of change of aging stage was the 6 th-12 th months when this period is just the stage of the rising storage environmental temperature,so the higher monthly temperature and the higher relative humidity of mellowing storage accelerated the degradation and translation of the total sugar and reducing sugar in tobacco strips.There were some visible differences(P<0.05)in the total sugar and the reducing sugar in different mellowing storage and different aroma types of tobacco strips.The decline range of total sugar and reducing sugar between clean-flavor and middle-flavor of tobacco strips in Xingyi high humidity and high temperature storage was greater than that in Guiyang and Guiding storehouses,but the differences of falling range of strong flavor tobacco strips were not significant.In the aging process of tobacco strips,the changes of the alkali content in different aroma types of tobacco strips of three mellowing storage were weak,and the change law of the sugar-nicotine radio synchronized with total sugar.So the higher monthly temperature and the higher relative humidity of mellowing storage became,the shorter its nature aging time became.3.Effects of different storing conditions on protein and amino acids contents of tobacco strips were studied in this research.Results showed that during aging process,the protein content of tobacco strips in different producing areas of three aging storehouse declined consistently.The content of free amino acid increased in the first 12 months of aging,then went down after 12 months of aging.The free proline content increased consistently,and the changing law of it was different from that of free amino acid.So conclusion could be drawn that little of the free proline in tobacco strips was oxidized during aging process.During 6 to 18 months of aging,there was significant difference in the protein content of tobacco strips for strong flavor and middle flavor type,but tobacco strips of strong flavor type no obviously.During aging of 12-18 months,extremely obvious significance of the free amino acid content was found in strong flavor type of tobacco strips.The protein and free amino acid content of tobacco strips in Xingyi storehouse was the largest than it in Guiyang and Guiding affected by environmental temperature and humidity,and there were differences for protein and free amino acid decreasing amplitude of tobacco strips stored in the same aging mellowing storage from different producing areas.Thus,storing condition had great compacts on protein and amino acid content in tobacco strips during aging,and then affected the aging quality and profits of tobacco strips.4.Effects of different storing conditions on ascorbic acid,polyphenol,carotenoids and their degradation products of tobacco strips were studied in this research.Results showed that during aging process,the degradation of Xanthophyll and ?-carotene in tobacco strips mainly occurred in 12-18 months of aging and the drastically increasing of carotenoids degradation products mainly occurred in 12-24 months of aging.While the degradation of chlorogenic acid,rutin and ascorbic acid content mainly occurred in 0-6 months of aging.The storing temperature affected the oxidation rate of polyphenol,ascorbic acid and carotenoids contents.Thus the oxidation rate of polyphenol,ascorbic acid,carotenoids and carotenoids degradation products contents in Xingyi mellowing storage was faster than Guiyang and Guiding mellowing storage,due to its higher monthly storing temperature.5.Endophytic bacterium in storing tobacco leaves vein of 6 raw material areas from Guizhou Industrial Co.,Ltd was screened and authenticated,and the enzymatic activity difference of degradation biological macromolecules produced by endophytic bacterium was analyzed.Results showed that eight strains of bacteria were screened from storing tobacco strips from different producing areas and could be classified into 6 category,authenticated by 16 S rDNA amplification and sequencing,and comparatively analysed by BLAST.The dominant bacterial community was Bacillus.Chryseobacterium sp bacteria community both existed in tobacco strips vein from Chenzhou,Hunan and Xuchang,Henan.Bacillus circulans bacteria community both existed in tobacco strips vein from Liangshan,Sichuan and Baoshan,Yunnan.Endophytic bacterium in tobacco strips of other producing areas were different.Production properties of tobacco leaves affected the population structure of endophytic bacterium in tobacco leaves vein which were closely related to producing areas and aroma type of tobacco strips.6.The activity of hydrolytic enzymes and oxidase of endophytic bacterium in tobacco strips was studied in this research.Results showed that endophytic bacterium in tobacco strips of different producing areas secreted ?-amylase,casein enzyme,polyphenol oxidase,peroxidase and ascorbate peroxidase,the activity differences were obvious in different endophytic bacterium.The activity of Bacillus producing alpha amylase and protease was high in leaf vein of Baoshan Yunnan,Liangshan Sichuan,Sanming Fujian and Zunyi Guizhou.The activity of chryseobacterium,micrococcus and Stenotrophomonas maltophilia producing enzyme was low in leaf vein of Chenzhou Hunan,Xuchang Henan and Zunyi Guizhou.The activity of Aeromicrobium and Stenotrophomonas maltophilia producing polyphenol oxidase,peroxidase and ascorbate peroxidase was high.7.Effect of enzymatic activity of endophytic bacterium on soluble sugar contents in tobacco strips from different producing areas during aging was studied.Results showed that the total sugar contents declined during aging process.The degradation rate of Xuchang Henan and Chenzhou Hunan was the fastest during 0-6 months and Baoshan Yunan was the fastest during 6-12 months.The reducing sugar contents firstly went up then declined during aging process.The increasing rate of Xuchang Henan and Chenzhou Hunan was the highest during 0-6 months affected by the variation of total sugar,and Baoshan Yunan was the fastest during 6-12 months,due to microbial metabolism and enzyme activity.There was significant linear positive correlation between the variation of soluble sugar and endophytic bacterium producing ?-amylase activity.8.The variation rule of protein and amino acids contents in tobacco strips during aging process was studied.Results showed that the protein contents in tobacco strips from different producing areas declined during aging process,and the degradation rate of Yunnan area was the fastest in 6-12 months of aging.The variation of amino acids went up in the first 12 months of aging,and the increasing rate of Baoshan Yunnan was the fastest.While it went down in the following 12 months aging,and the degradation rate of Liangshan Sichuan was the fastest.There was significant linear positive correlation between the variation of protein and amino acids contents and endophytic bacterium producing protease activity.9.The variation rule of antioxidants contents like ascorbic acid in tobacco strips during aging process was studied.Results showed that during 0-6 months of aging,the degradation rate of lutein and ?-carotene was faster in Xuchang Henan and Chenzhou Hunan,and the degradation rate of polyphenols and ascorbic acid was faster in Baoshan Yunnan,Sanming Fujian and Liangshan Sichuan.While during 6-12 months of aging,the degradation rate of antioxidants was fast in Zunyi Guizhou.It was found that there was extremely significant positive correlation between oxidase activity and the variation of antioxidants. |
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