Study On Performance Of Modified Starch-chitosan Edible Film

Cross-linked hydroxypropyl starch、blended with water-soluble chitosan were studied in this paper, using glycerol as its plasticizer, and casting method was used to produce the edible film. By testing, the overall performance are best when the rate of solid content of the starch solution and chitosan solution is1:1, the highest tensile strength of the cross-linked hydroxypropyl starch-water soluble chitosan edible film reaches38.15MPa, which increases33.33%to the water soluble chitosan edible film; the biggest elongation is66.12%; which increases29.14%to the water soluble chitosan edible film; while the minimum value of the oxygen permeability coefficient and the moisture permeable coefficient respectively reach1.76x10-14cm3?cm/cm2?s?pa and1.90x10-12g?m/m2?s?pa. Stearic acid, palmitic acid, the mixture of stearic acid and palmitic acid (mass ratio:1:1) were respectively added to the blending solution, the results performed that lipoid material can improve the barrier property of the edible film, and the improvement effect of the edible film which was added the mixture of stearic acid and palmitic acid was best among the three lipid film, the oxygen permeability coefficient and the moisture permeable coefficient of edible films contending lipoid materials respectively decreased55.49%and63.64%to edible films without lipoid materials. Some making membrane technical such as gelatinization temperature of the starch、stirring speed of blending, stirring time of blending were studied and how can they affect the performances of the film, and SEM was used to analysis it, the results turned out that the proper gelatinization temperature of starch was about90℃, and the proper stirring speed of blending was550r/min with stirring time of blending50min, while it’s ensile strength reaches36.29MPa, the elongation is72.21%, and the oxygen permeability coefficient and the moisture permeable coefficient respectively reach0.75x10-14cm3?cm/cm2?s?p and0.69x10-12g?m/m2?s?pa.Put several edible films with better comprehensive properties in the environment of the same temperature while the relative moistures are respectively33%,43%,65%,75%,90%, testing the variation of the films on mechanical properties, oxygen resistance and so on during a month. As a result, the edible films became crisp with the relative moistures of33%and43%, while too soft with the relative moistures of75%and90%, when the relative moisture is65%, the film has mild softness and stable properties. And then, produce some little bags which can package oilseeds, dehydrated vegetables, and salt for instant noodles, according the change of these products during a month, it turned out that the edible films can protect the products.