Emulsion Enzyme In Tobacco Fermentation Process

How to improve the quality of tobacco leaves and to shorten the aging time of tobacco are two problems to resolve impatiently for all tobacco enterprises. As aqueous enzyme is not stable, the enzyme's catalytic role is limited and the quality of the degraded tobacco is not good. For these reasons, in this thesis, the study was focused on improving the internal quality of tobacco leaves and accelerating tobacco aging by adding emulsion enzymes.Main positive results were as follows:1. Selection of water soluble carriers and actives for the emulsion enzymes and preparation of stable emulsion.Nine kinds of water soluble carriers which were biology compatibility were studied, in which carriers such as Arabic tree gum, sodium alginate and chitosan had certain promotive effects on the smoking quality, gelatin and PEG had no effects, and the other four had negative effects. Combining with the nature of the carriers and the stability of emulsion, sodium alginate and Arabic tree gum were determined as the water soluble carriers for preparing emulsion.25 kinds of enzymes were studied, in which 10 kinds of enzymes such as cellulose, pectase, amylase, protease and so on, were selected as resources of enzyme to improve the quality of low grade tobacco leaves and accelerate tobacco aging, because they could improve the smoking quality. And A was used as a stabilizer for preparing emulsion enzyme according to its influence on the residual activity of enzyme.The effects of type and use level of emulsifier and carriers, use level of stabilizer, emulsion temperature, emulsion time and stir speed on the viscosity and residual enzyme activity of the emulsion were investigated. The optimum conditions for preparing stable emulsion were determined as follows:emulsifiers were sucrose ester and Span-60, and m(sucrose ester):m(Span-60)=5:3; carriers were sodium alginate and Arabic tree gum, and m(sodium alginate):m (Arabic tree gum)=1:15;w(stabilizer A)=0.3%-0.4%; emulsion temperature 20～30℃; emulsion time 3 h; stir speed 400-500r/min. The residual activity of emulsion enzyme could be improved more 25% than that of aqueous enzyme, and the reasons were discussed in the article.2. Studies on improvement of the upper tobacco quality by adding emulsion enzyme or aqueous enzymeThe improvement effect of emulsion enzyme or aqueous enzyme including amylase, protease, cellulose and pectinase respectively on the upper tobacco leaves was investigated. According to the degradation ratio of responding polymer components in tobacco and the improvement of smoking quality, process conditions such as degradation temperature, use level of enzyme, degradation time, moisture content of tobacco were studied emphatically. And the optimum conditions were determined, and following conclusions could be drawn: the degradation ratio of each chemical ingredient had a positive correlation with the amount of corresponding enzyme, degradation time and moisture content of tobacco, but non-linear. And the ratio had a positive correlation with degradation temperature at first, but negative correlation later. However, the smoking quality had no entirely positive correlation with the reducing extent of the ingredients. Degradation time of the emulsion enzymes was 3-6h longer than that of the aqueous enzyme, and degradation temperature was 5～10℃higher, which hinted that under the protection of the emulsion membrane, the stability of enzyme was improved. It was also showed that the degradation ability of starch, protein, holocellulose, pectin by adding emulsion enzyme was 9%-11%,6%-7%,2%-3%, 4%-6% higher respectively than that by adding aqueous enzymes, which was consistent with the improvement of the enzyme's stability of emulsion.Mixed enzymes could decompose and invert holocellulose, starch, protein and nicotine in B3F. The degradation ratio of above mentioned compositions by adding emulsion enzyme was 3.78%,7.69%,3.43% and 5.25% higher respectively than that by adding aqueous enzymes. Mixed enzymes could also increase the accumulation ability of organic acids, amino acids, volatile components and reducing sugar. The accumulation ability of above mentioned compositions by adding emulsion enzyme was 0.22%,0.35%,1.69μg/g and 6.35% higher respectively than that by adding aqueous enzymes. The tar in B3F degraded by emulsion enzyme was 0.49mg/cig. less than that by aqueous enzyme, so the safety of smoking cigarettes could be improved by adding emulsion enzyme. In addition, the qualities of tobacco degraded by emulsion enzyme were better than that by aqueous enzyme in aroma quality, after-taste, and offensive odor.3,The applied research on promoting natural aging of tobacco by adding emulsion enzyme Aging process of the test and check samples of three tobacco leaves B2F,C3L,X2L was studied. Test and check samples which were aged 0,1,3,6,12,18 months were taken and the characters such as characteristic compositions in smoke, conventional chemical compositions, superficial structure, and aroma components of tobacco leaves were analyzed. The results showed that for the two samples the smoking quality was positively correlated with aging time, and so was the transformation or degradation ability of the major ingredients in tobacco, but non-linear. Chemical compositions of the tobacco leaves changed greatly in the earlier stage, and slowly in the later. In the earlier stage emulsion enzyme could accelerate the reduction, transformation, accumulation of the chemical compositions in tobacco. It could also reduce irritancy and physiological strength, eliminate offensive odor, increase aroma quality and quantity, and improve after-taste in smoke. In addition, emulsion enzyme had the greatest impact on B2F, followed by C3L, and minimal X2L, and could shorten aging time of the B2F tobacco more than 12 months, C3L and X2L 6 to 12 months respectively.4,The change rules of enzyme activity in the process of tobacco natural fermentationAfter the activity of enzyme in tobacco aged 0,1,3,6,12,18-month was analyzed, the change rules of the enzyme activity was concluded. In the initial fermentation activity in test samples was much higher than that in check samples. To the test samples, the activity of saccharidase, cellulose and protease was negatively correlated with aging time. And the activity of amylase, pectinase decreased at first, increased 3 months later, and kept up a steady decrease after six months. The activity of polyphenol oxidase increased during the first month, and later kept up a steady decrease. To the check samples, the activity of amylase, cellulase, pectinase, and protease increased during the first six months, decreased six months later. The activity of polyphenol oxidase increased quickly during the first 3 months, decreased later. The activity of enzyme in test and check samples was close after aging18 months.5,The correlations between the change rules of enzyme activity and the chemical constituents of tobaccoAfter the correlations between the change rules of enzyme activity and the degradation rules of the chemical constituents of tobacco were studied. For all the 3 kinds of tobacco, the higher the enzyme activity was, the faster the degradation of the chemical constituents. In the initial fermentation activity in test samples was much higher than that in check samples, and so was the inversion rate of the chemical constituents, so emulsion enzyme could improve the process of tobacco natural fermentation. To the check samples, the enzyme activity was high during the first six months, and the degradation of the chemical constituents was fast too, and later, with the decline of the activity, the degradation decreased. In addition, with the type of the tobacco changing, the degradation ability of enzyme was different.6,In this part, the action mechanism of emulsion enzymes and the degradation course of starch, holocellulose, protein, pectin and polyphenols were analyzed.The major innovations are:1. There is creation in research method:First time, emulsion enzyme was used to improve the quality of tobacco leaf and promote the aging process.2. There is creation in characterization method of emulsion stability:Viscosity and residual enzyme activity were used to characterize the stability of emulsion.3. First time, the correlations between the change rules of the activity of cellulose and pectinase and the chemical constituents of tobacco in the aging process were studied.4. First time, the change rules of enzyme activity in tobacco aging process were studied after emulsion enzyme was added.