Study On Preparation Technology Of Pectic Polysaccharides And Nano-Cellulose Of Okra Fermented Wine Pomace

Wine pomace,also known as wine lees,is a mixture of fermented grains of wine after distillation.There are many pectic polysaccharides and insoluble dietary fiber in the okra pomace.Using okra fermented pomace waste to prepare nanocellulose can not only turn waste into treasure but also reduce environmental pollution.This paper studies the process of preparing pectin polysaccharide and Nano-Cellulose by using okra fermented pomance.And the preparation of okra Nano-Cellulose edible film and its application in fruit preservation were discussed.The results are as follows:1.Using okra fermented pomace as raw material,pectic polysaccharides were extracted by ultrasound-assisted method of okra fermented pomance.The single factor experiment and response surface design were used to optimize the extraction process.The optimum conditions were:extraction temperature 64℃,liquid-solid ratio=1:44,extraction time 42 min,ultrasonic power of 350 W.The extraction rate of pectic polysaccharides under this protocol was 9.65%.2.Taking the cellulose after extracting the pectin polysaccharide as a raw material,okra fermented pomance NCC is prepared by sulphuric acid hydrolysis method.The optimum conditions for preparation of NCC are determined through single factor experiment and Box-Behnken test response surface.The optimum conditions were:acid solution temperature 60℃,acid solution duration 120 min,sulphuric acid concentration 45%,liquid to solid ratio=1:17,and 21.07%of NCC yield ratio.NCC ultrastruture is represented by adopting Transmission Electron Microscope（TEM）,Fourier Transform Infrared Spectroscopy（FTIR）and X-Ray Diffraction（XRD）.The analysis results show that the diameter of NCC prepared by sulfuric acid hydrolyzation is 100 nm.It presents rodlike structure,but it is very easy to agglomerate due to hydrogen bonding.Moreover this method does not have much influence on the group of the okra fermented pomace NCC,and it still has the most basic chemical structure of cellulose.The okra fermented pomace NCC belong to typical of CelluloseIType crystal structure with a crystallinity degree of 65.14%.3.The edible film is prepared by taking okra fermented pomace NCC as filler and blending sodium alginate.The optimum conditions for preparation of NCC-SA edible film are determined through single factor experiment and Box-Behnken test response surface.The optimum conditions were:the concentration of NCC mass is 0.83%,the concentration of sodium alginate mass is 2.54%,and concentration of glycerine mass is 1.01%.Under such circumstance,the tensile strength of edible film is 23.06 MPa,the elongation at break is 83,16%,and water vapor permeability is 1.58×10^-10(g·cm^-1·s^-1·Pa^-1).The SEM and FTIR analysis show that the denseness of the edible film is better,and the film forming materials have good compatibility.4.The prepared Nano-Cellulose edible film is used for preservation experiment of fresh cherries.The results showed that the weight loss rate and the decay rate of the cherries packaged in the edible film bag during storage were lower than those of the control group,while the hardness,soluble solid content,titratable acid content and Vc content were increased.The explains that edible film can reduce cherry nutrition loss,further prolong the storage period,better maintain the appearance quality of the cherry and ensure excellent preservation effects.