明胶添加量对兔皮明胶膜特性与结构的影响

Effect of gelatin additions on the properties and structure of rabbit skin gelatin films

从兔皮中提取明胶制备明胶膜,通过测定不同明胶添加量下膜的机械性能、水蒸气透过率、亚基组成和结构,探究明胶添加量对明胶膜特性与结构的影响。结果表明随着明胶添加量的增加,明胶膜体系内网络空间结构变大,从而膜的厚度增加。力学结果显示,明胶添加量为4 g/100 m L(w/v)时,明胶膜抗拉强度最高(p<0.05);明胶添加量为6 g/100 m L(w/v)时,明胶膜断裂伸长率最低(p<0.05)。水蒸气透过率结果表明随着明胶添加量的增加,水蒸气透过率呈现上升趋势。凝胶电泳结果显示,明胶添加量为4 g/100 m L(w/v)时,低分子量的蛋白组分产生更多交联,形成蛋白质-蛋白质交联的结构,此浓度下明胶膜的抗拉强度最大。FT-IR分析表明:当明胶添加量增加至4 g/100 m L(w/v)时,酰胺A带向高波数移动,说明肽链上的N-H基团并没有与甘油的-OH基团相互反应,而是明胶分子的官能团之间产生更强的相互作用,形成独特的网络结构。同时,酰胺Ⅰ带曲线拟合结果也表明当明胶添加量为4 g/100 m L时,膜内稳定结构较多,明胶分子之间的相互反应达到最大化,明胶膜的稳定性和成膜性能较优。

The effect of gelatin additions on the properties and structure of rabbit skin gelatin films was studied by measuring the mechanical properties, water vapor permeabilities, subunit content and structure. The results showed that the thickness increased because gelatin network structure in the gelatin film system increased with increasing the addition of gelatin. Mechanical property results showed that the tensile strength of gelatin films was the highest when the addition of gelatin was 4 g/100 niL（w/v）,however the gelatin films possessed the highest elongation at break as the addition of gelatin was 6 g/100 mL（w/v）. The water vapor permeahilities of gelatin films increased with increasing the gelatin additions.The results of sodimn dodecyl sulfate-polyacrylamide gel electrophoresis（SDS-PAGE） indicated that the low molecular weight of protein fraction formed protein- protein cross- linking which resulted in the highest tensile strength as the gelatin addition was 4 g/100 mL（w/v）. FT-IR results showed that amide A band moved to high wave number as the gelatin addition was 4 g/100 mL（w/v） , which indicated that glycerol molecules didn＇ t react with N-H group of peptides. A greater interaction occurring between gelatin functional groups to form a unique network structure conversely.Furthermore, curve-fitting of amide I band showed that there were more stable structure in the film matrix as the gelatin addition was 4 g/100 mL（w/v） , so the films possessed greater stability and film-forming properties.