| Edible biopolymer packaging become a hot topic at home and abroad packagingmaterials. KGM is a polysaccharide extracted in konjac tuber, the wide variety of sources,with good water retention, film formation and gelation, also with lowering blood pressure,blood sugar and other physiological functions, is an excellent edible film substrate, but itsthermo-reversible gel reunion and limit the range of applications, this article by addingmethyl cellulose, KGM overcome their shortcomings, for KGM-methylcellulose ediblefilms were studied.This article from the three aspects of KGM-MC edible films were studied. Namely:preparation of edible film KGM-MC, KGM-MC basic performance edible films andstructures affect the micro microwave ultrasonic modification on KGM-MC edible filmproperties and structures. Specific contents and conclusions are as follows:(1) Preparation KGM-MC edible film by single factor experiment showed that theoptimal range of factors: methyl cellulose dosage0.2~0.4%(w/v), glycerol dosage0.5~1.0%(v/v), homogeneous time is3~9min, drying temperature is40~60℃, the pH valueneutral. On the basis of single factor, for preparation of edible film KGM-MC optimization,established the optimum conditions. Were obtained for water vapor permeability of variousfactors (WVP), elongation at break (E), tensile strength (TS) of the effect size and theoptimal combination, obtained by the equation to get the comprehensive optimization ofmethyl cellulose added an amount of0.235%(w/v), glycerol added in an amount0.61%(v/v), the drying temperature is51℃, when the homogenization time was6min, TS,E, WVP relatively better three indicators were10.4210-10g/m·s·Pa,105.87%,10.25MPa.(2) MC influence on KGM-MC edible film properties by adding different content:With the increase of MC, E increases after the first smaller, T increases, MC’s dosage0.3%(w/v) when most water-blocking performance well, along with enhanced thermalstability; by FT-IR and SEM technology analyzes the impact of the added amount of MCKGM-MC membrane structure, after KGM and MC blend film, synergistic synergybetween the two substances, to form a uniform and orderly matrix structure, and generates anew chemical bond; also studied KGM-MC membrane isothermal hygroscopicity, GABmodel best fitted thereto.(3) Microwave, ultrasonic, microwave-ultrasound synergy of KGM-MC edible filmwas modified to study its effects on the mechanical properties of edible film KGM-MC,water blocking performance and light transmission, and through the three-factor quadraticgeneral rotary ultrasonic synergistic combination microwave test optimization modifiedoptimum conditions. WVP as an index, when the microwave power is200W, microwavetreatment time of17min, ultrasonic treatment time was17min, the steam KGM-MC ediblefilm reaches the minimum transmission coefficient, as3.4510-10g/m·s·Pa; E as an index,when the microwave power is400W, microwave treatment time was15min, the ultrasonic treatment time was25min, the elongation at break KGM-MC film reaches a maximum of131.81%; with TS as indicators, when the microwave power is400W, microwaveprocessing time15min, ultrasonic treatment time was15min, the tensile strength ofKGM-MC film reaches a maximum for21.86MPa.(4) Microwave-ultrasound combination system KGM-MC modified edible films andstudy their microstructure changes. By FT-IR spectra can be seen in the microwave-Ultrasonic synergy only through external mechanical force makes KGM-MC mixedsolution of molecular rearrangement, to improve its mechanical properties and waterresistance performance; by contrast SEM and AFM chart, KGM-MC film was seen in thefield of microwave and ultrasonic cavitation dual role, molecules in a magnetic field rotatesviolent rearrangement of the film formed on the surface of a large and highly uniformcircular projection surface roughness increases, surface energy lower; by measuring thecontact angle of KGM-MC film, the contact angle increases after modification to verify themodified surface water blocking performance improvement. |
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