可食性膜阻水特性的研究

Research on Water Vapor Barrier Properties of Edible Films

本实验采用拟杯子法,以CaCl2为吸水材料,以棉布为膜载体,在温度25±2℃、相对湿度为90%±2%的条件下,测定了各种膜的水蒸气透过率,并比较了它们的阻水特性。结果表明,海藻酸钠膜是具有最佳阻水性的多糖膜;明胶膜比大豆蛋白膜阻水性更优;脂质膜的阻水率按以下顺序依次增大:月桂酸<棕榈酸<硬脂酸<石蜡<蜂蜡,乙酰化单甘酯的阻水性优于单甘酯;增塑剂山梨醇、甘油及乙二醇的加入会使膜的阻水性降低;在三元膜中,脂质膜用作被膜剂比用作乳化剂具有更好的效果。

In this experiment the method of modified cups was utilized to determine the water vapor permeability of every coating at 25 ±2 ℃ and 90%± 2% relative humidity, and their water vapor barrier properties were compared with CaCl2 as absorbent and cotton-cloth as coating carrier. The results indicated that the water barrier property of sodium alginate was the best in the polysaccharide-based coatings; the water vapor barrier property of gelatin was better than that of soy protein; water vapor barrier rate of lipid-based coatings increased as follows＂ lauric acid 〈palmic acid〈stearic acid〈wax〈beeswax, water vapor barrier; and property of acetyl monoglyceride was better than that of monoglyceride. The addition of plasticizers, e.g. sorbite, glycerol and ethylene glycol may decrease water vapor barrier property. It was better for the lipid-based coatings used as film formers than as emulsifiers.