Studies On The Extraction And Separation Of Flavonoids From Fresh Alfalfa

Medicage stativa L. is perennial leguminous grass which is one of the main popular and applied forage in China. At present, Alfalfa has been developed and utilized as a resource of protein both at home and abroad. The main by-products of alfalfa leaf protein extracted from are residue and waste liquid, which contains the alfalfa flavonoids. Flavonoids can eliminate free radical, and has functions of anti-oxidation, anti-tumor and estrogen-like, which has a broad application prospect. Therefore, this topic has researched the separation and purification of total flavonoids from waste liquid. The purpose of the studies was to provide a scientific proof for the comprehensive exploitation and utilization of industrial waste liquor after extracting leaf protein, thereby to open up a new way to improve the alfalfa economic value.1. Method the extraction conditions of flavonoids from alfalfa hay were optimized by single factor and complete orthogonal tests.The results showed the ethanol concentration was70%, extraction temperature was80℃, extraction ratio of1:20of material liquid, extraction time was90min. At the same time, we extracted the total flavonoids from the eight kinds of alfalfa in different harvest and measured their contents. In June, August and November, three harvest time of flavonoids content, variety "sadie5","queen","suntory","sadie7","visitors"(P<0.05), the flavonoids content of alfalfa were reached significant level varieties in November is significantly higher than in June and August (p<0.05).2. We used alkali extraction and acid precipitation, as well as acid and heating extraction, investigated the optimum extraction of leaf protein and the total flavonoids from alfalfa. The best process parameters obtained by the incomplete orthogonal test is definded.By referring to the indicator of ratio of leaf protein and total flavonoids. Leaf protein and Medicage flavonoids by alkali extraction and acid precipitation is as follows:extracting solvent was pH.10, precipitating solvent was pH.4.5,precipitating time is32min. The extracting amount of leaf protein was16.61lmg/g, and the extracting amount of total flavonoids is0.365mg/g. Leaf protein and Medicage flavonoids by acid and heating extraction is as follows:precipitating solvent was pH. 5.1, heating temperature was85℃, precipitating time is11min. The extracting amount of leaf protein was18.085mg/g, and the extracting amount of total flavonoids is0.384mg/g.3.The adsorption effects of three macro-porous resins (AB-8, D101and HPD750) on flavonoids from Alfalfa was studied. Through static adsorption and desorption experiment, AB-8was selected as the adsorption resin because of its higher adsorption and desorption rate. Through the dynamic adsorption-desorption of macro-porous resin AB-8, the optimum dynamic elution condition was:concentration of sample was0.528mg/ml, eluted with3BV70%ethanol, the purity of flavonoids crude extraction of flavonoids was48.52%.