The Extraction And Application Of The Pectin From The Bark Of Mulberry Stalk

The paper mainly studies on the comprehensive utilization of mulberry branch’s bark which produced in sericultural industry as by-product for the purpose of enhancing economic benefit and social effect of silkworm industry. In branches of comprehensive utilization of sericultural resources, the total output of mulberry twigs is high and little is fully used. The output of mulberry swigs harvested in summer is possible to reach500to800kg per mu. As a natural product, pectin is broadly used in food industry and pharmaceuticals industry for its treatment in diabetes.Pectin’s extraction from mulberry bark and its hypoglycemic treatment has been investigated in the experiment; the experimental result has been provided the theory reference for the comprehensive utilization mulberry twigs.Take mulberry bark as raw materials, using ammonium oxalate-oxalic acid hydrolysis ethanol precipitation to extract pectin from it, the optimum process conditions of pectin extraction from bark of mulberry stalk are obtained, namely rate of material to solvent1:14, pH2.0, temperature90℃,120min, the pectin product yield ratio reaches to about12%.Using ammonium oxalate-oxalic acid hydrolysis ethanol precipitation to test the extraction rate from different parts of bark of Morus multicaulis Perr(Husang32) harvested in summer. The results showed that the extraction rate (extract from fresh bark) differs in different parts. The stem base of annual mulberry reached a highest extraction rate at12.4%. The newborn mulberry bark reached11.8%. The pectin yield of Husang32, Nongsang8, Nongsang14and Yu711were different. Husang32reached a highest ratio at12.4%. Rest of them ranked in from12.1%,11.6%to10.8%.Gather some branches of Husang32in different period (spring, summer, autumn) and different parts (upper, middle and basal) to determine their pectin extraction rate respectively.The result showed that pectin extraction rate is high in middle part of spring and autumn mulberry, then basal and upper part. Summer branches’pectin extraction rate in basal part of is higher than annual upper part. The difference in pectin extraction rate spring and autumn branches was not significant. The pectin extraction rates in middle part were12.3%and12.1%respectively; the pectin extraction rates in basal part were11.4%and11.7%respectively. The pectin extraction rate of summer branches was12.4%in basal part and12.1%in upper part. Compared with spring and autumn branches, the pectin extraction rates of summer ones were somewhat higher.The extraction rate of fresh skin is higher than the dried ones. The changes of pectin yield rates were compared by storing the barks of mulberry stalk form1to12months with artificial drying and natural drying treatment respectively. The results showed that the the extraction rate of mulberry bark by artificial drying is higher than natural drying and the pectin extraction rate is11.3%,8.3%,7.5%and6.3%for mulberry bark stored in1,3,6, and12months in natural condition and11.8%,9.3%,8.5%and7.3%in artificial drying conditions, respectively.Take little white rats as experimental animals to test pectin’s hypoglycemic effect through feeding experiment. The results showed:pectin extracted from mulberry bark had hypoglycemic effect for diabetic rats.Feeding these groups for two weeks with low and high dose of pectin and diabetes pills metformin glibenclamide respectively, their blood sugar level decreased11.33%,13.17%and18.91%. For four weeks, it decreased16.78%,18.20%and23.81%. The pectin could cushion diabetic rats’loss of weight and increase their food-intake and water-intake at the same time.These results provide theoretic basis for the utilization of mulberry resource and have significant values for accelerating the production and efficiency of sericulture and increasing farmers’income. The experiment of hypoglycemic effect of pectin extracted from mulberry bark pointed a direction for the further development of diabetes drugs and healthy food.