| In the paper, the edible composite films are made from chitosan as main membrane material and with glycerol as the plasticizer, add a kind of biological active component-lentinan, new types of edible composite films are prepared by blade casting process.The composite films are determinated with tensile strength, elongation at break, water vapor permeability, oxygen resistance and opacity as main index. The conditions of preparing films are optimized by Design Expert. The best conditions as following:chitosan content 2.10%(w/v), lentinan content 0.69%(w/v), and glycerol content 19.12%(percentage of the quality of chitosan and lentinan). After chitosan dissolved in 1.5% acetic acid solution, lentinan dissolved in water, mix and stir, control the drying temperature is 60?, The results indicate that tensile strength is 29.78MPa, elongation at break is 12.32%, water vapor permeability is 3.427×10-11g/(m·s·Pa), oxygen resistance(express by peroxide value of oil) is 4.605g/100g, and opacity is 20.205%.The influence on structural compatibility of lentinan content characterize by IR and XRD. Results show that lentinan caused the migration and the strength change of composite films characteristic absorption peak, made its diffraction peak weakened or even disappeared. Description of composite films have good compatibility between components.Before the edible films used in flexible packaging materials, the sealing process of making bag is necessary. Effect of adhesives concentration, sealing temperature, heat sealing time, heat sealing pressure on composite films sealing strength are studies. And on the basis of single factor experiments, The sealing process is optimized by orthogonal experiment. The result show that the best technology of heat sealing composite films:heat sealing temperature is 140?, heat sealing time is 3.5s, heat sealing pressure is 0.3MPa. Under these conditions, the sealing strength of the composite film is up to 12.03N/15mm. |
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