有机酸改性对玉米醇溶蛋白膜机械性能的影响

Effect of Organic Acid Modification on Mechanical Properties of Zein Film

玉米醇溶蛋白成膜性好,然而其膜机械性能差,影响了它的实际应用效果。改性是弥补这一缺点的有效手段。选用乙酸、乳酸、琥珀酸、苹果酸、酒石酸与柠檬酸6种有机酸来对玉米醇溶蛋白改性,结果表明:在玉米醇溶蛋白含量为0.1 g/mL;乙醇体积分数90%;羧酸添加量0.03 g/mL;加碱改性溶液pH 5.0;反应温度60℃;反应时间30 min条件下,无碱苹果酸改性膜延展率达到(228.17±26.53)%,相比对照组提升154%,而其抗拉强度仅为(0.70±0.05)MPa。碱催化柠檬酸改性膜抗拉强度由(7.18±0.54)MPa提升至(12.73±1.05)MPa,延展率为(3.65±0.21)%,与对照组差距不大。经改性后的玉米醇溶蛋白膜机械性能良好,不仅为它在食品保藏方向的应用打下基础,而且有利于我国玉米产业链的延伸,促进产业成熟。

Zein was known by good film-forming property,but zein film mechanical properties problem affect its effectiveness in practical applications,modification was the effective way to solve the problem.In this paper,acetic acid,lactic acid,succinic acid,malic acid,tartaric acid and citric acid were used to modify zein.When the zein content was 0.1 g/mL;the ethanol volume fraction was 90%;the carboxylic acid amount was added 0.03 g/mL;the alkali-modified solution pH was 5.0;the reaction temperature was 60℃;the reaction time was 30 min.The results showed that non-alkali malic acid modified zein film extending rate was(228.17±26.53)%,which increased 154%compared to the control group,but its tensile strength was only(0.70±0.05)MPa.Alkali catalytic citric acid modified zein film tensile strength increased from(7.18±0.54)MPa to(12.73±1.05)MPa,its extension rate was(3.65±0.21)%,which had no significant difference with the control group.The modified zein film had good mechanical properties which not only laid a foundation for its application in food preservation,but also facilitated the extension of China’s corn industry chain and promotes industrial maturity.