Preparation Of Okra (Abelmoschus Esculentus L.) Acid-Soluble Pectin And Its Antioxidant,Anti-Pancreatitis Activity Study

Okra(Abelmoschus esculentus L.)was rich in pectin polysaccharides,which had the functions of protecting stomach,promoting digestion and detoxifying.However,there were few reports on acid-soluble pectin of okra.Acute pancreatitis was an acute digestive disease caused by a variety of causes.The body would suffer oxidative stress during acute pancreatitis,which increased the risk of multiple organ failure syndrome.The currently used gastrointestinal targeted antibiotics for treatment had a greater impact on intestinal microbes.Therefore,it was of great significance to seek natural active substances for dietary supplementation to prevent the further deterioration of acute pancreatitis.To this end,this paper used okra as the raw material,using response surface methodology to optimize the heating acid hydrolysis extraction process of okra crude acid-soluble pectin,and then further separation by column chromatography to obtain the okra acid-soluble pectin component.The physical and chemical properties and structure were analyzed,and finally,its antioxidant activity and anti-pancreatitis activity were discussed.The main research results were summarized as follows:(1)The processing technology of extracting crude acid-soluble pectin from okra by heating and acid hydrolysis was optimized.The best extraction conditions were indicated as below:p H value was 4,ratio of liquid to material was 20 m L/g,extraction temperature was 50?,extraction temperature was 50 min,extraction rate was 19.23%.(2)The physicochemical properties and structure of acid-soluble okra pectin co-mponents were analyzed.In terms of physicochemical properties,the contents of total sugar,uronic acids,protein and esterification degree of acid-soluble crude okra pectin(CAOP)and purified acid-soluble okra pectin(AOP)were compared.AOP was composed of four monosaccharides,GalA,Gal,Rha and Xyl,respectively.The relative content ratio of monosaccharides was 79.1:4.3:14.5:2.1.The molecular weight of AOP was 9.28×10~4Da.AOP was a kind of amorphous polymer with smooth surface and good thermal stability.The results of FT-IR and ~1HNMR showed that it matched with the composition analysis of monosaccharides,and the possible connection of monosaccharides were deduced.(3)Antioxidant activity and anti-pancreatitis activity of acid-soluble okra pectin components were studied in vitro.Both AOP and CAOP had good antioxidant activity,and AOP showed higher antioxidant activity,which may be related to the difference in chemical composition between the two.In the RAW 264.7 macrophage experiment,AOP could significantly inhibit the inflammatory response induced by LPS.At the same time,AOP protected the intestinal mucosal barrier function and reduced the inflammatory response of acute pancreatitis by improving the expression of sIgA in intestinal mucus,promoting the expression of tight junction protein in intestinal epithelial cells and up-regulating the content of intestinal endogenous antimicrobial peptides.