Extraction Of Jerusalem Artichoke Polysaccharide And Preparation Of Its Edible Composite Membrane

Jerusalem artichoke is a kind of medicinal and edible plants that is resistant to cold and drought and have strong adaptability to soil.Its underground tubers are rich in fructose polymers such as starch and inulin,which leads to its high research and application value.Jerusalem artichoke polysaccharide,abbreviated as inulin,is a chain-like plant storage polysaccharide made up of fructose molecules connected by?(1?2)glycosidic bonds.Jerusalem artichoke polysaccharide is not only widely used in the food processing industry such as baking,dairy products,beverages and seasonings,it plays a role in improving the texture and taste of food,improving the water retention of meat,and maintaining the stability of food,but also because of its different degree of polymerization,it has the physiological functions of dietary fiber and biologically active precursors,proliferates bifidobacteria in the intestines,and improves intestinal health;regulates blood sugar levels;controls blood lipids;and can also promote the absorption of minerals to a certain extent,and the synthesis of vitamins.Therefore,inulin has broad development prospects.This paper starts with in-depth research on the optimization of Jerusalem artichoke polysaccharide-chitosan edible composite membrane(Jerusalem artichoke polysaccharide-chitosan edible composite membrane,abbreviated as JPEM)and its application.The results are as follows,(1)Study the best technological conditions for hot water extraction and ultrasonic extraction of Jerusalem artichoke polysaccharides.The material-to-liquid ratio,extraction temperature and ultrasonic time were selected as the test variables,and the yield of Jerusalem artichoke polysaccharide was used as an indicator to conduct a single factor test.Then,according to the test results,three optimal levels of variables were selected to design a response surface test,and the data obtained.Analyze and discuss to get the best combination of extraction parameters.The test results show that the order of the influence of each variable on the yield of polysaccharides is:ultrasound time>material-to-liquid ratio>extraction temperature,the optimal extraction conditions are that the ratio of material to liquid is 1:17(g/m L),the extraction temperature is 39?,the ultrasonic time is 46 min,and the extraction yield of Jerusalem artichoke polysaccharide is 8.43%.(2)Using the inulin and chitosan to make a composite membrane,selecting the amount of Jerusalem artichoke polysaccharide,the amount of glycerin,and the drying temperature as the influencing factors,and conduct a single factor test.And according to the single factor test results,three superior levels are selected to design the orthogonal test,determine the physical indicators of the membrane(thickness,density,solubility,opacity,water vapor transmission rate),mechanical properties(tensile resistance and elongation at break)and Fourier infrared spectroscopy for structural characterization.According to the results of each index,the membrane prepared under the conditions of Jerusalem artichoke polysaccharide content of0.50%,glycerol addition of 25%,and drying temperature of 55°C was selected.At this time,the various performance indicators of the membrane are as follows:thickness is 0.088 mm,density is 1.192 g·cm^-3,solubility is 25.23%,opacity is 2.07,water vapor transmission rate is3.477×10^-11 g·m·(m²·S·Pa)^-1,the tensile strength is 24.64 MPa,and the elongation at break is7.63%.(3)Prepare a single chitosan membrane solution and a composite membrane solution with a concentration of Jerusalem artichoke polysaccharide of 0.75%,and apply them to leafy vegetables with high transpiration.The test results show that the water loss rate of rapeseed treated with the composite membrane solution containing 0.75%Jerusalem artichoke polysaccharide is 19.72%lower than that of the rapeseed treated with a single chitosan membrane solution;the water loss rate of spinach treated with the compound membrane solution containing 0.75%Jerusalem artichoke polysaccharide was 21.11%lower than that of spinach treated with a single chitosan membrane solution.It is proved that Jerusalem artichoke polysaccharide can interact well with chitosan and improve the fresh-keeping performance of the membrane.