Study On The Fermentation And Pharmacological Action Of Yacon Leaf

The paper taking the yacon leaves as the research object, yacon leaves was processed into tea in foreign country, and the tea have the effects of hypoglycemic, reducing blood lipid and detoxification. But the tea taste bitter. The researches show that:there are rich compositions of flavonoids, phonetic acids and polysaccharides, have the pharmacological effects of protesting liver, antioxidation, hypoglycemic, bacteriostasis, anti-atherogenic and so on. The paper aims at changing the yacon leave tea's taste, and keeping or improving the pharmacological effects. The paper includes six chapters below.Chapter one gives a review of the research process of yacon leaves, the review introduces the nutritional components, functional components, pharmacological effects and so on mainly.In chapter two, the paper studies the fermentation of yacon leaves. Through compareding with the fermentation methods of normal temperature with no-adding microorganism, normal temperature with adding microorganism, constant temperature with no-adding microorganism and contents temperature with adding microorganism. It studies the effects of temperature, water content and microorganism on fermentation. The best fermentation was determined by the changing of the taste and functional components. The study show that:the best fermentation was:the water content was 30%, the temperature was 40℃, adding the lactobacillus and yeast, the time was 21d. Through fermentation, the tea taste sweet, the color was excellent, and the tea keep the functional component, the yacon leaves were suitable for exploiting health tea.In chapter three, the paper studies the pharmacological effects of yacon leaves fermentation pre and post. The results show that:the extracts of 70% alcohol have the highest activity of anti-glucosidase; the extracts of butanol have the highest activity of anti-glucosidase. The hypoglycemic substance in yacon leaves have excellent thermal stability, and affinity with a-glucosidase. The animal model further show:the one of the hypoglycemic mechanisms is correcting the imbalance antioxidant system and-scavenging free radicals.In chapter four, the paper studies the antioxidation activity of yacon leaves fermentation pre and post by DPPH·method. The results show that:the extracts of 70% alcohol of yacon leaves fermentation pre and post have the highest activity of antioxidation and the extracts of butanol have the highest activity of antioxidation, the free radical scavenging activity was 82.49%. Through fermentation, the yacon leaves'antioxidation decreased small amplitude, because the antioxidation substances of yacon just like phonetic acids were oxidized.In chapter five, the paper studies the antibacterial activity of yacon leaves fermentation pre and post to staphylococcus aureus, pseudomonas aeruginosa, escherichia coli and malassezia. The results show that:the extracts of yacon have strong antibacterial activity to the four microorganisms. Through fermentation, the yacon leaves'antibacterial activity to staphylococcus aureus was increased, and the same to the malassezia, the antibacterial activity to the pseudomonas aeruginosa haven't changed, but the extracts'antibacterial activity to the escherichia coli was decreased. Before fermentation, the minimum inhibitory concentration of yacon leave to the four microorganisms were 0.065g/mL,0.025g/mL,0.025g/mL,0.0325g/mL, respectively. After fermentation, the minimum inhibitory concentration of yacon leave to the four microorganisms were 0.03g/mL,0.025g/mL,0.03g/mL,0.03g/mL respectively.Chapter six summarizes the research and forecast the future.