Studies On The Technology Of Extracting Hesperidin By Ultrafiltration And Enzyme Modification

China is one of the main citrus growing in the globe, where citrus production ranks the second all over the world at present. Application of citrus fruit in food and medicine has long history. According to the epidemiological and animal researches, citrus fruits are rich in large quantities of bioactive compounds related to human health. Hesperidin, a bioflavonoid is an abundant by-product from citrus processing and with significantly pharmacological effect, including vascular system, anti-inflammatory and anti-carcinogenic activity. Although hesperidin has been reported to possess a wide range of pharmacological properties .Most of citrus peels were wasted in the citrus processing industry. Moreover, because of its poor solubility, it has not been widely used. This paper studies Ultrafiltration extraction condition, enzymatic modification conditions of hesperidin, and purification and characteristic of modificated hesperidin. The main results were listed as follows:(1) Hesperidin derived from citrus peel extraction was separated by UF method. The effect of transmembrane pressure (TMP), axial flow-rate, temperature, the volume concentration rate (VCR) of hesperidin extraction on ultrafiltration permeates flux, and different cleaning agents on the recovery of membrane flux were investigated. Through studying the effect of different molecule weight cut off and material protoplasmic membrane on extraction efficiency of hesperidin, the polypropylene membrane was selected. The optimum conditions were determined as: the ultrafiltration membrane with 30,000 MWCO should run at TMP 0.25Mpa, temperature of 30℃, axial flow rate of 80 L/h and VCR 3.4; The purity of hepseridin obtained was more than 85% after crystallization; the cleaning efficiency was highest using 0.1%HCl and 0.1%NaOH, the water flux of the fouled membrane was recovered. The above results indicated that the elimination rate of pectin by UF was to the pectin elimination rate achieves 91.3%; the hesperidin interception rate is 12.5%. Furthermore, flux decreased with increase of treatment time, the initial flux is higher 16L/ h, the permeating flux decreased by 43% from 0 min to 20 min due to gel formation.(2) The single factor experiment discovered that the pH of reaction system should be controlled in 6 to 8, the reaction temperature 50-60℃, with enzyme quantity 800 IU / g, the conversion rate of hesperidin is highest when reaction substrate choice dextrin, the reaction time is 24 h;Different temperature,pH and enzyme quantity were studied based on single factor experiment. The reaction conditions were optimized through Response Surface Analysis (Box-Benhnken's Center Composite Design).The functional relationship between main factors and response value were established, and the regression equation was obtained. The regression equation was as follow:Y = 79.79 +1.35 A+2.79 B +5.83 C +2.52 AB-2.58AC +0.375 BC-11.73A~2-16.20B~2 +1.31 C~2 Obtains through analyzing the regression equation: enzyme quantity is the most remarkable to the conversion rate of hesperidin in various factors, the factor correlation is small, the enzyme modified hesperidin optimum response condition was optimized: temperature of 55, pH of 7 and enzyme quantity of 800, pH is 7, adds the enzyme quantity is 800IU/g, its correspondence's response value (Y) is 79.79%, obtains the model forecast value confidence level through the verification test to be high.(3) Compared with three kind of resins (D101, D296, HP-10) to the adsorption characteristic of hesperidin, HP was selected to perform. The HP-10 resin to hesperidin tendency saturated adsorptive capacity is the 1844ug/mL wet resin; The optimum pH of 10 and the speed of flow of 1.0mL/min; were obtained, hesperidin desorption condition: the eluent is 50% ethyl alcohol, the eluent amount used is 300ml, the elution speed of flow is 1.0mL/min; Modified hesperidin desorption condition: the eluent is 70% ethyl alcohol, the eluent amount used is 300ml,the elution speed of flow is 1.0mL/min,concentrated, on distinction column once more. The elution curve obtained through resin HP-10 chromatographic and HPLC analysis of the modified hesperidin pure was the sole symmetrical peak.Therefore,overpass the experiment, we can obtain that the modified hesperidin pure was the sole component, and its purity achieves 92.3%,rate is 4.99%.(4) The modified hesperidin pure assumes white powder which is no smell and were readily soluble in water, sodium hydroxide and hydrochloric acid appeared to be the best solubility; It is very difficult to dissolve in benzene and chloroform. The absorption peak of hesperidin and modified hesperidin by UV scanning are same (λ=285nm) ,IR scanning showed that the structure of modified hesperidin determines initially as glycosyl hesperidin.