Preparation And Preservation Properties Of Edible Film Material Bagasse Hemicellulose Groups

With the intensification of energy, resources, environmental issues and changes in the concept of resources utilization, it has become a new trend for the extraction of hemicelluloses, transformation and development which comes from the residues of traditional agriculture. This thesis chooses bagasse from the residual by-product after the extraction of juice from the crushed stalks of sugar cane as raw material, and focuses on the efficient extraction and high value-added. This article discussed the pre-extraction process of bagasse hemicelluloses, physicochemical properties and hydrolytic kinetics, and also investigated the feasibility and fresh-keeping of preparation of edible membrane materials which derived from bagasse hemicellulose-based.Based on the analysis of chemical composition of bagasse material, this paper studies the effect of alkali charge, temperature, time of extraction, borax charge and solid-to-liquid ratio for hemcelluloses yield of bagasse or bagasse powder, respectively. The results showed that the dissolution rate of hemicelluloses up to15.01%(to the hemicelluloses content in material) when the alkali charge was50%(based on NaOH)and borax charge was5%at a liquid-to-solid ratio of20:1at90℃for10hour during the conventional bagasse alkali/borax pre-extraction of hemicelluloses system. Under similar conditions, the time of the smashed sugar cane bagasse reduced to70%.The bagasse hydrolysis dynamics analysis showed that the dissolution kinetics stage concludes the main degradation and dissolution stages and residual degradation and dissolution stages. The hydrolysis kinetics of bagasse alkali pre-extraction and pentosan degradation reactions all belong to pseudo first order reaction. Analysis of the composition and the content of the extracted hemicelluloses by ion chromatography displayed that the highest content of the hemicelluloses was glucose, also contained a large amount of arabinose, xylan, galactose, rhamnose and small amounts of mannose and glucuronic acid. X-ray diffraction showed that bagasse hemicelluloses contain large amounts of amorphous region and small amounts of microcrystalline structure. GPC analysis showed that hemicelluloses have a certain degree of degradation but preferably uniformly under the conditions of the alkali treatment.In homogeneous N, N-dimethyl formamide (DMF)/anhydrous lithium chloride (LiCl) solvent system, to promote acetic acid anhydride modified hemicelluloses on the optimum conditions of80℃for4h with1%catalyst and the esterifying agent concentration of25%, the accessibility of hemicelluloses reached to1.36.Bagasse hemicelluloses or modified hemicelluloses as raw materials to study and obtain optimization of hemicelluloses-based edible coating material preparation process system. Research the physical properties effect of hemicelluloses modification pre-and post, chitosan, the concentration of glycerol, pH values and drying temperature of the composite membrane. The membrane structure was characterized through methods of infrared spectrum (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscope (AFM). The results showed that:hemicelluloses charge of1.2%, Chitosan concentration of0.48%, glycerol dosage0.7%, pH values2.5, drying temperature of55℃. Good strength properties and barrier properties could be obtained under this condition. The water vapor permeability coefficient values below0.50g·mm/m2·h·KPa. The results of hemicelluloses basement membrane material by FT-IR and NMR analysis showed that hemicelluloses without substantial changes in structure. The analysis of SEM and AFM found the hemicelluloses-edible film material had a good surface characteristic.Mixing hemicelluloses/acetylation of hemicelluloses with chitosan to prepare of coating antistaling liquid, and use for the Baozhu pear preservative to test the effect of coating antistaling liquid for pear by detecting the weightlessness rate, the appearance of the rate of change of pear, water content, active acidity (pH), total sugar, amino acid and vitamin C at room temperature. Results indicated that hemicelluloses/acetylation hemicelluloses-chitosan complex mixed coating film has a significant fresh-keeping performance of the Baozhu pear.