明胶-甘油-酪蛋白酸钠原位组装复合膜及分析

Situ Assembly of Composite Films Prepared by Sodium Caseinate with Gelatin and Glycerol

首先将牛奶中提取的酪蛋白在温度为95℃、0.5mol/L的NaOH溶液中水解3h,然后同甘油和明胶进行组装制膜。研究了甘油和明胶添加量对所制复合膜的拉伸强度和断裂伸长率以及阻水和阻氧性能的影响,并根据成膜组分的分子结构和作用特性,分析了成膜机理。结果表明,甘油和明胶的加入能显著提高复合膜的力学性能,改善膜的阻水和阻氧能力。当甘油、明胶和酪蛋白质量比为0.16∶0.80∶1.0时,膜的拉伸强度、水蒸气透过率和过氧化值分别为58.11MPa、4.44×10-6g/(m·h·Pa)和-7.52 meq/kg。明胶中氨基和羧基的存在同甘油的羟基和酪蛋白中的氨基和羧基之间的次级键作用是协同成膜的主要原因。

Casein, obtained from fresh milk, was hydrolyzed for 3h in order to form sodium caseinate under the condition of 95 ℃, 05mol/L NaOH solution. The composite film was prepared by glycerol, gelatine and sodium caseinate. The properties, such as tensile strength, elongation, water vapour permeability and peroxide value of the composite films, were emphatically investigated and its forming mechanism was also discussed. The results show that the mechanical properties of composite films, barrier properties for gas and water vapor are obviously improved with the addition of gelatine. When mass ratio of glycerol, gelatine and caseinate is 0.16∶0.80∶1.0 , the tensile strength, water vapour permeability and peroxide value of the composite films are 58.11MPa, 4.44×10-6 g/（m·h·Pa） and -7.52 meq/kg respectively. The main reason of synthetically forming film is that lots of hydrogen bonds are formed between amidocyanogen and carboxyl in gelatine and casein.