| The active ingredients in sweet rice wine and Lithocarpus litseifolius (Hance) Chun were investigated in this paper.Lithocarpus litseifolius (Hance) Chun, alias Sweet Tea, which is a medicinal and edible plant. It has three kinds of functions of tea, medicine and sugar. The leaves of Lithocarpus litseifolius (Hance) Chun have high sweetness after soaking, so it was called Sweet Tea(ST). Phloridzin and trilobatin are the main sweet components in Sweet Tea. Modern pharmacological studies have shown that ST have a wide range of biological activities, such as hypoglycemic, antihypertension, antiallergic, anti-oxidative, improving memory. These effects are associated with flavonoids in ST. Therefore, the quality control of ST based on the determination of flavonoids. In this paper the total flavonoids from leaves of Lithocarpus litseifolius (Hance) Chun was extracted with 70% methanol, and the crude extract was dissolved with water and extracted with different polarity solvents (petroleum ether, ethyl acetate and n-butanol). Then, ethyl acetate extraction was isolated and purified by macroporous resin, silica gel column chromatography and Sephadex LH-20. The isolated compounds were identified by means of MS,’H-NMR and 13C-NMR spectra. Compounds were identified as phlorizin, trilobatin,3-hydroxy phlorizin and kaempferol-3-O-β-D-glucoside. Reversed phase high-performance liquid chromatography (RP-HPLC) method was developed for simultaneous determination of eight flavonoids (3-hydroxy phlorizin, isoquercitrin, phlorizin, quercetin, phloretin, quercitrin, kaempferol-3-O-β-D-glucoside and trilobatin) in ST from Yunnan, Jiangxi and Hunan. Comprehensive survey and analysis of effect of the temperature of chromatographic column, flow rate, the ratio of the mobile phase and the optimum conditions:kromasil C18 column (200×4.6 mm,5 μm), the UV detection wavelength at 257 nm, the mobile phase was 0.1% glacial acetic acid aqueous solution (A)/methanol (B) at a flow rate of 1.0 mL/min, the temperature of chromatographic column at 25 ℃, injection volume was 10 μL, chromatography analysis for 40 min. Program of HPLC gradient elution:0-10 min,35-40% B; 10-35 min,40-65 %B; 35-40 min,65-80% B. The result showed that phlorizin and trilobatin were the main components in ST and the quality of ST was greatly influenced by harvesting time, location and leaf age. The active components of Lithocarpus litseifolius (Hance) Chun were studied in this experiment, which provided a theoretical basis for the further development and utilization of Lithocarpus litseifolius (Hance) Chun.Sweet rice wine is a sweet and full-bodied traditional snacks. It has functions as activate blood circulation and reducing swelling and so on. It is also the best of tonifying blood for weak body. At present, most sweet rice wine is brewed through traditional process, which is loved by most consumer because of being unique taste and flavor of glutinous rice. Sweet rice wine is rich in a variety of vitamins, amino acids and glucose. In this study, changes in contents of phenolic acids and amino acids in the fermentation process of sweet rice wine were investigated. The high performance liquid chromatography method was employed to determination of phenolic acids. The optimized chromatographic separation conditions:kromasil C18 column (200×4.6 mm,5 μm), the UV detection wavelength at 280 nm, the mobile phase was 0.1% glacial acetic acid aqueous solution (A)/methanol (B) at a flow rate of 1.0 mL/min, the temperature of chromatographic column at 25 ℃, injection volume was 10 μL, chromatography analysis for 50 min. Program of HPLC gradient elution:0-5 min,5-22% B; 5-28 min,22-22% B; 28-32 min, 22-47% B; 32-36 min,47-50% B; 36-40 min,50-60% B; 40-45 min,60-80% B; 45-50 min,80-80% B. The result showed that six phenolic acids were detected in sweet rice wine. The content of phenolic acids showed a rising trend in the fermentation process. The content of phenolic compounds in rice wine was various in different fermentation stages. The increase in the content of catechins is the fastest. The content of catechins is the highest and the quercetin is the lowest at the end of fermentation. Anion exchange chromatography with integrated pulsed ampere detection methods was used determine the amino acids in the sweet rice wine. Chromatographic separations were achieved using AminoPac PA 10 anion exchange column. The mobile phase was water,250 mmol/L sodium hydroxide solution and 1 mol/L sodium acetate solution at a flow rate of 0.25 mL/min, the temperature of chromatographic column at 30 ℃, injection volume was 10 μL, chromatography analysis for 30 min. The result showed that the content of amino acids in sweet rice wine is rich, which mainly was composed of sweet and bitter taste amino acids. The sweet rice wine sample has the best sensory evaluation, which has the higher amino acids content than the initial fermentation liquor samples.This study provides an important scientific basis for optimal brewing of sweet rice wine,which also is to prepare for therealization of the industrial production of sweet rice wine... |
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