Complex With The Enzyme Aging Of Flue-cured Tobacco

The aging of the tobacco leaf is an acknowledged method to improve the leaf flavoring property and its usability. The leaf aging concluded crude aging and artificial fermentation. The crude aging spent too long time and had higher cost, meanwhile artificial fermentation could't get the better quality. Therefore, so many researchers devoted themselves to study the aging mechanisms and its condition. They hoped to search for a better method to ferment leaf that could not only control cost but also have good quality.In this thesis, we had selected 10 enzymes which could improve the leaf's characteristic from 25 enzymes. The 10 enzymes were distinguished into two classes: primary enzyme and assistant enzyme. The primary enzyme included cellulase from Aspergillus fumigatus (the enzyme activity is 50000u/g), pectinase from Aspergillus fumigatus (the enzyme activity is 1 800 000u/g), a -amylase from Trichodema(the enzyme activity is 100 000u/g), thermostable amylase (the enzyme activity is 40 000u/g), pullulanase (the enzyme activity is 10 000u/g), which proportion was 2:3:2:2:1. The assistant enzyme included neutral proteinase from Aspergillus fumigatus (the enzyme activity is 5000u/g),lipase from Aspergillus fumigatus (the enzyme activity is 12000u/g), polyphenol oxidase(the enzyme activity is 1200u/g), pentosanase (the enzyme activity is 5000u/g), β -1,4-glucosidase(the enzyme activity is 300000u/g) and the proportion was 1:2:2:2:3. Then we combined these enzymes with the suitable steady liquid to make the aging fluid of the flue-cured tobacco. The proportion of the primary enzyme and the assistant enzyme was 3.5:1. The dilution proportion was 4000:1 to 6000:1.Then, the comparison experiment about 4 kinds of first-cured tobacco leaves was respectively carried out in the threshing and redrying and aging. The result indicated that the aging fluid could degrade the leaf cell wall substances, accelerate the increasing of total volatile acids content and the decreasing of the wikipedia substance content. Meantime it had no effect on the contents of chlorine, potassium, the reducing sugar, total nitrogen, protein, total nicotine and volatile alklines. After 6 months, the quality of the artificial fermentation leaf was better than that of the crude aging leaf. The improvement effect of the aging fluid on the quality of the upper leaves and middle leaves were superior to that of lower leaves.In the experiment, the method that can isolate and mensurate the cell wall substance was improved and detailed. The results showed that the coefficient of variation of the cell wall substance content was 1.11% -5.05%, the coefficient of variation of total cellulose content was 2.47%-6.34%, the coefficient of variation of the pectin content was 5.00%-5.25%. After the process error was eliminated, the coefficient of variation mentioned above were 0.55%-2.69%, 0.79%-1.46%, 1.82%-3.86%.