Preparation And Properties Of SA-CMC-LBG Ternary Blend Film

Edible film is made with biodegradable polysaccharide,protein as the main agent,edible polyol as plasticizer,or hydrophobic agent(lipid),enhancer by a certaintreatment process.It has a certain mechanical properties and barrier properties,both toprotect food quality,reduce food safety problems;also biodegradable,to avoidpolluting environment.It is a promising green packaging material,also is currentlythe development trend.Firstly,the paper is systematically compared the film-forming properties of 21kinds of plant gums the most studied in the literature.Through measuring the glue'sapparent viscosity,transparency and the film's thickness,transparency,watersolubility,together with the sensory judgment,the results showed that sodium alginate,sodium carboxymethyl cellulose and locust bean gum had the best film-formingperformance,then the three kinds of plant gums were used as the raw material ofblending film.Secondly,a new ternary blend film was prepared by adding sodium alginate andsodium carboxymethyl cellulose as main film-forming materials and locust bean gumas auxiliary film-forming material,and glycerol as plasticizer.The effects of the blendratio of sodium alginate/sodium carboxymethyl cellulose/locust bean gum,theamount of glycerin and the sol temperature on the ternary blending glue's apparentviscosity,transparency and the film's transparency,mechanical properties,moistureresistance and water solubility were investigated.The optimum conditions ofpreparation of the ternary blend film with better comprehensive properties weredetermined by single factor experiment and orthogonal test.The total concentration ofthe blend solution was 2.8%,the blending ratio was 4/5/1,the glycerol content was0.75%,and the sol temperature was 80?.Under these conditions,the tensile strengthof the ternary blend film could reach 40KPa,the elongation at break is the highest,which is as high as 67%,the water vapor permeability coefficient is 1.6257×10-2g·mm/m ·h·KPa,the moisture resistance is good,the water solubility is 5.278×10-2g/min,and the film is smooth,transparent,transmittance is as high as 85.3%.The compatibility of sodium alginate/carboxymethylcellulose/locust bean blend film was characterized by FT-IR,SEM and TG.The results showed that there was a strong hydrogen-bond interaction among three components and no obvious phase separation at the macroscopic and microscopic levels,so the ternary blend film had good compatibility.Finally,sodium alginate/sodium carboxymethyl cellulose/locust bean gum composite coating agent was prepared according to the best formula,then fresh-keeping experiment of fresh grapes was carried out.The effects of the coating agent on the hardness and weight loss of the grape were studied.The results showed that the composite film-forming agent played a role in preserving the grape,having certain application prospects.