不同相对湿度环境条件下玉米醇溶蛋白膜的稳定性研究

以不同蛋白浓度、甘油添加量和成膜温度制备玉米醇溶蛋白膜,研究其在不同相对湿度(RH)条件下24 d储藏过程中的机械性能变化。结果表明:不同条件下制备的玉米醇溶蛋白膜,在中低相对湿度(34%、43%、54%)条件下24 d的储藏过程中,膜的抗拉强度(TS)呈现先增加后减少的趋势,而断裂延伸率(EB)则呈现先减少后增加的趋势。而在80%的高湿度环境中,不同蛋白浓度和不同成膜温度制备的蛋白膜,储藏期间TS呈现逐渐增加的趋势,EB则快速减少;不同甘油含量的膜,在RH80%环境中TS和EB的变化趋势与RH34%、RH43%和RH54%一致。RH65%环境条件下蛋白膜的机械性能的变化受成膜条件的影响较大。整体上看,储藏过程中环境湿度对玉米醇溶蛋白膜的机械性能的影响大于制备条件的影响。因此,在蛋白膜的研究中,应用的环境湿度也是需要考察的重要因素之一。

Stability of zein films at different relative humidity

Zein film was prepared under different zein concentration, glycerol ratio and forming temperature, and the change of their mechanical properties during 24 days storage at different relative humidity (RH)was determined. The results showed that tensile strength (TS)of the film prepared under different preparing conditions decreased firstly and then increased while the elongation at break (EB)changed on the contrary at RH34%, RH43%, and RH54% during 24 d storage. TS of the film prepared under different zein concentration and forming temperature increased gradually, and EB decreased rapidly at RH80%, but the trend of TS and EB of film with different glycerol ratio at RH80% was in accordance with those at RH34%, RH43%, and RH54%. The change of mechanical properties of zein film at RH65% was affected markedly by the forming condition. In general, effect of RH on the mechanical properties of zein film was more obvious than their preparing condition. Ambient humidity of film application should be taken into the effect factor in order to develop effective film.