Study On The Extraction And Modification Of Pectin From Pitaya Peel

Pectin is a fiber widely exists in plant with the traits of gel properties and safety. It is widely used in foods, medicine and cosmetics as thickening material, stabilizing agent and emulsifying agent. In recently years, more and more research showed that the low molecular weight pectin has the activities of antialcoholism, lead elimination, anti-tumor and regulating blood fat. Now most of pectin studies focus on the modifying and extraction on low esterification degree pectin. The extraction technology and modified technology of pectin from pitaya peel was investigated, and its antialcoholism activity was studied in this paper. The research results provide the experimental date and theory evidence to the pectin exploitation. The main content and results as the following:By investigating the influences of acid species, ratio of material to liquid, pH value, extraction temperature and extraction time to yield, molecular weight and esterification degree of pectin extracting from pitaya peel, characterizing the extraction pectin products with molecular weight and esterification degree, the acid extraction technological conditions pectin from pitaya peel were set up. The results showed that the preferable acid extraction condition were the following:the acid was H2SO4at concentration0.05mol/L, the ratio of material to liquid1:10, the extraction temperature at95℃and extraction time for140min. The yield, molecular weight and esterification degree of pectin was not change evidently in the procedure of amplification process. The products under this condition were the primrose yellow powder with the molecular weight between50000and60000and the esterification degree between40%and44%. The production belongs to low esterification degree and middle molecular weight pectin, using for exploitation on functional foods of eliminating lead and antialcoholism.The influences of enzyme species, enzyme concentration, ratio of material to liquid, pH value, extraction temperature and extraction time to yield, molecular weight and esterification degree of pectin extracting from pitaya peel were investigated, and extraction pectin products were characterized with molecular weight and esterification degree, and the enzyme extraction technological conditions were set up. The results showed that the preferable enzyme extraction condition were the following: the enzyme was cellulose, the quantity added to4mg/g, the ratio of material to liquid1:30, the extraction temperature at40℃and extraction time for120min. The molecular weight and esterification degree of pectin was not change in the procedure of amplification process but the yield was a little reducing. The products under this condition were the light grey powder with the molecular weight between40000and50000and the esterification degree between36%and40%. The production belongs to low esterification degree and low molecular pectin, using for exploitation on functional foods of eliminating lead and improving immunity. Compared to the acid extraction method, it had the merits of short production cycle, mild production conditions, higher yields, environmental protection and lower producing cost. This technology was worth popularizing.The influences of alkali species, alkali concentration, reaction temperature, reaction time and ratio of material to liquid to molecular weight and esterification degree of pectin modified by alkali technologies were investigated, and alkali modified pectin products were characterized with molecular weight and esterification degree, the alkali modified technological conditions were set up. The results showed that: the influencing factors of alkali modified technological conditions of pitaya peel pectin were the following: alkali concentration, ratio of material to liquid, the hydrolysis temperature and hydrolysis time. The preferable alkali modified condition were the following: the alkali specie was potassium hydroxide, alkali concentration1%, the ratio of material to liquid1:10, the hydrolysis temperature at30℃and hydrolysis time for30min. The molecular weight and esterification degree of pectin was not change in the procedure of amplification process. The molecular weight below10000and the esterification degree was under10%of the modified pectin producing by this technology.The hydrolyze the methyl ester bond and molecular degradation laws of pectin when pectinase and pectinesterase recombination were investigated, and modified pectin products were characterized with molecular weight and esterification degree, the technological conditions were set up. The results showed that: the influencing factors of modified technological conditions of pitaya peel pectin were the following: enzyme concentration, ratio of material to liquid, the hydrolysis temperature and hydrolysis time. The behavior of hydrolyzing the methyl ester bond play the main roles at low temperature and molecular degradation play the main roles at high temperature. The modified pectin produced by enzyme technology owning the characters with molecular weight between20000and40000and esterification degree between20%and30%. The molecular weight and esterification degree of modified pectin can be controlled by controlling the hydrolyzing the methyl ester bond time and temperature, the hydrolysis time and temperature. The better double enzyme recombination technology conditions were the following:50g pectin powder added to1OOOmL water mixing to well-distributed pectin solution, heating the temperature to65℃, regulating the pH value of solution to2.8, then cold the temperature to30℃, adding1.5%pectinase, mixing, hydrolyzing the methyl ester bond180min, disorder the activity of pectinase; adding0.15%pectinesterase, mixing, hydrolysis for120min, obtain the low esterification degree and low molecular weight pectin solution, then through alkali neutralization, filtration, desiccation and comminuting, the modified pectin were obtained. The molecular weight was from20000to40000and the esterification degree was from20%to30%of the modified pectin producing by this technology.By investigating the difference of the pectins with different molecular weight and degree of esterification on antialcoholism and avoid be drunk effects of mice, the pectin type with the effects of antialcoholism and avoid be drunk has been compared through animal experiments. The results showed that: the key roles of pectin’s action of against alcohol were not the content of galacturonic acid but the molecular weight and esterification degree of pectin. The pectin with low molecular weight and low esterification has the better antialcoholism effects than other pectin type. The pectin with low esterification degree and high molecular has the better effects avoid be drunk than other pectin type.