Study On Extraction,Preparation And Functional Properties Of Polysaccharide From Shaddock Peel

The yield of shaddock increases year by year,however,the remaining pomace in the processing has not been effectively utilized.It not only brings pressure to the environment,also a waste of resources.In this paper,the functional properties and physicochemical properties of shaddock peel were analyzed,and the food additives were developed with shaddock peel polysaccharides as raw materials.The extraction rate of shaddock peel polysaccharide was improved by ultrasonic assisted enzyme method,made the feasibility and suitability of processing clear.The main results of this research were as follows:1.Extraction of shaddock peel polysaccharides were optimized by ultrasonic assisted enzyme method.The optimum parameters were solid to liquid ratio 1:30,pH6,enzyme dosage 1.7%,cellulase and pectinase ratio 1:1,enzymolysis time 1.2 h,enzymolysis temperature 50℃,ultrasonic time 29 min and ultrasonic temperature70℃.In these conditions,the extraction rate of shaddock peel polysaccharides(Ⅰ)was82.4%,the yield was 27.3%and the purity was 46.2%.2.The DPPH,ABTS and hydroxyl radical scavenging capacities of shaddock peel polysaccharides(Ⅰ)were analyzed.The results showed that shaddock peel polysaccharides had good DPPH scavenging capacity,strong ABTS scavenging ability,but the ability to scavenge hydroxyl radicals was common.The antibacterial activity of shaddock peel polysaccharides was studied.The results showed that shaddock peel polysaccharides had inhibitory effect on Escherichia coli and Bacillus subtilis.The inhibitory effect on Escherichia coli was better.3.Composition analysis showed that shaddock peel contained 1.3%fat,6.2%protein,12.2%pectin and 12.6%polysaccharides.The yields of shaddock peel polysaccharides with 5 different ingredients were obtained by different preparation methods.The yield were:water extraction group(A)6.3%,fat retention group(B)11.1%,pectin retention group(C)7.8%,protein retention group(D)21.2%,and all removal group(E)20.8%.4.The analysis of the functional properties of 5 groups of polysaccharides and the properties of bread both showed that the shaddock peel polysaccharide with the retention of pectin composition(Ⅱ)had better emulsification,thickening and stability.The removal of some small molecule alcohol soluble impurities in the alcohol degreasing process could promote the properties of shaddock peel polysaccharides.5.The weight average molecular weight of shaddock peel polysaccharides(Ⅰ),(Ⅱ)was determined by gel chromatography.The weight average average molecular weight(Mw)of shaddock peel polysaccharides(Ⅰ)were 2.085×10~5Da and 6.136×10~3Da respectively.The corresponding peak areas were 93.4%and 6.6%respectively.The weight average average molecular weight(Mw)of shaddock peel polysaccharides(Ⅱ)were 4.902×10~5Da and 2.535×10~3Da respectively.The corresponding peak areas were 94.5%and 5.5%respectively.The results showed that ultrasound assisted enzyme method could effectively reduce the molecular weight of shaddock peel polysaccharides.6.The rheological properties of shaddock peel polysaccharides(Ⅱ)have been studied.The results show that the shaddock peel polysaccharides solution is a non Newtonian fluid,there is a phenomenon of shear thinning and presents a certain pseudoplastic behavior.While the concentration of shaddock peel polysaccharides solution increases,the modulus of energy storage G’is higher than the modulus of viscosity G",and the solution tends to elastomer.