Study On Extraction Process Of Pectin From Potato Residues And Polemo Peel

Agricultural wastes are concerned as the source of pectin. In this paperthe sulfuric acid carbazole method for the determination of pectin wasdetermined to test. The abundant starch must be degradated by the enzyme inthe potato and sweet potato residue. After the pretreatment of potato residue,sweet potato residue and pomelo peel, the extraction of pectin from the threeagricultural wastes were optimized to solve the optimal extraction conditions,and the properties of pectins extracted from three kinds of raw materials werestudied.The sulfuric acid carbazole method was a conventional methods fordetermination of pectin,so the test was very necessary to determinate itsreaction condition.In the condition of6ml of sulphric acid, the effect of thecarbazole adding amount and color of time was studied on the determinationof each pectin concentration and the final determination conditions wereidentified as carbazole adding quantity of0.2mL and2h chromogenic time.When the enzymatic hydrolysis conditions were controlled in pH6.5,temperature65℃, the enzyme dosage of the potato residue and the sweetpotato residue respectively was20u/g and16u/g and the enzymatic hydrolysis time was60min. The starch removal rates was up to93.27%and96.58%.By the single factor and response surface experiment: the extractionconditions of the potato residue pectin,sweet potato residue pectin and pomelopeel pectin was pH1.45,1.33,1.33hydrochloric acid,stirring speed100rpm,90℃,87℃,99℃hot water and extraction time87min,92min,60min and thepectin extraction rate separately was5.61%,7.13%,38.9%and the ratio ofsolid to liquid respectively is1:16,1:20and1:30.The physicochemical properties and gelation properties of the three kindsof pectin were determined. The final comparison showed the other two kindspectin more lower gelation performance was poor, far below the pomelo peelpectin. It was closely related to the pectin structure and high ash content.