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Garlic can food and medicine, and its highest content of functional ingredients are garlic fructan, has antioxidant, anti-virus, enhance immunity, protect the liver and other effects, in the food, pharmaceutical and cosmetic industries have great potential applications. Garlic fructan bioactive size, their structures have an important relationship. But garlic fructan structure remains unclear. This thesis is to be adopted by methylation, hydrolysis, GC determination and other means of garlic fructan structures. The main results are: (1) Garlic by water extraction, cation-exchange resin separation, alcohol fractionation, DEAE-52 and Sephadex G-100 column chromatography. Garlic fructan, Sephadex G-100 column chromatography Identification it is pure. (2) optimize the sulfuric acid hydrolysis of garlic fructan conditions. Effects of garlic fructan hydrolysis degree factors were hydrolysis temperature gt; hydrolysis time gt; sulfuric acid concentration, the best combination of factors is sulfuric acid concentration of 0.02mol / L, 70 ℃, hydrolysis 2h; highest degree of hydrolysis of 76.19%, then conditions: sulfuric acid concentration of 0.020 mol / L, the hydrolysis temperature is 70 ℃, hydrolysis time was 2.5 hours. (3) to optimize the sulfuric acid hydrolysis methylation garlic fructan conditions. Impact permethylated garlic polysaccharide hydrolysis degree factors were sulfate concentration gt; hydrolysis temperature gt; hydrolysis time, the best combination of factors is sulfuric acid concentration of 0.40 mol / L, 100 ℃, hydrolysis 6 h; highest degree of hydrolysis of 34.28% , when conditions are: sulfuric acid concentration of 0.40mol / L, 100 ℃, hydrolysis of 7 hours; trifluoroacetic acid (TFA) hydrolyzing the methylation garlic fructan: Measured maximum degree of hydrolysis of 65.87% at this time conditions : TFA concentration of 0.5mol / L, 100 ℃, hydrolysis of 4 hours, the best combination of factors is the TFA concentration of 0.50 mol / L, 100 ℃, hydrolysis 6h. With TFA hydrolysis methylation garlic fructan obtained a degree of hydrolysis greater than the sulfuric acid hydrolysis and methylation garlic fructan in TFA was dissolved sufficiently, indicating that TFA is more suitable for the hydrolysis of methylation garlic fructan. (4) to analyze Hydrazone, a hydrazone reaction mechanism, and based on the reaction mechanism of synthesis of polysaccharide derivative, the phenyl hydrazine, 2,4 - dinitrophenyl hydrazine with a 5% glucose, fructose solution reaction, detection of the reaction speed, and then by mass spectrometry (MS) and thin layer chromatography (TLC) to detect the reaction product. The results showed that: a Hydrazone reaction product more, reaction speed, glucose and fructose into Hydrazone time was 5.3 minutes and 2.4 minutes, glucose and fructose into Hydrazone reactions occur in C1 and C2 bits, the di-substituted reaction product of the two or more; a hydrazone reaction rate is slow, fewer by-products, 2,4 - dinitrophenylhydrazine glucose, fructose solution reaction into a hydrazone times in 24 hours or longer, the reaction happened respectively C1 or C2 position, the mono-substituted reaction product only one. Analysis showed that the carbonyl reagent spatial effects and electronic effects affect both sugar substitute quantity and speed of response. In generating the derivative in the reaction prone to side reactions, the carbonyl reagent solution in acetic acid and phenyl hydrazine, 2,4 - dinitrophenylhydrazine reaction of acetyl phenylhydrazine, and 2,4 - dinitro hydracetin . (5) the garlic fructan methylation, hydrolysis, reduction, acetylation, by GC-MS line analysis, measured garlic fructan degree of branching is higher than 17%.
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