Pectin Methyl Esterase-Modified Pectin Extracted from Ougan(Citrus suavissima Hort.Ex Tanaka)Peel by Acid Method
In order to fully utilize Ougan(Citrus Suavissima Hort.ex Tanaka)peel resource and increase industrial added value,acid method was used to extract pectin from Ougan peel(named CP1),and then CPI was modified by pectin methyl esterase into product labelled as EMP1 in this paper.The process conditions for acid-extracted pectin were optimized by orthogonal experiments,and physicochemical properties,structural characteristics,and in vitro antioxidant activity of the pectins before and after modification were analyzed and compared,so as to obtain the best process conditions and low molecule polysaccharide with high biological activity.The results showed that the optimal extraction conditions for the extraction of the Ougan peel pectin by acid method were 95 ℃,pH value 2.0,extraction time 90 min,and solid-liquid ratio 1∶50,under these conditions,the extraction rate of pectin from Ougan peel was(22.33±0.40)％.The content of galacturonic acid(GalA％)in EMP1(89.64％)was significantly higher than that in CP1((84.97±1.44)％)whereas its molecular weight(7840 g/mol)and degree of esterification(32.42％)were significantly lower than those of CP1(309062 g/mol and 85.53％,P＜0.05).The content of monosaccharide composition,ratio of crystal type and surface structure of pectins before and after modification were different,and the antioxidant activity of modified pectin was improved in dependence on its concentration.In summary,the modified pectin had lower molecular weight,higher purity,and good antioxidant activity,which could provide theoretical reference for their applications in the food industry.
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