玉米醇溶蛋白膜增塑剂的选择优化及其对膜体阻湿性能的影响

SELECTION AND OPTIMIZATION OF PLASTICIZERS AND THEIR EFFECTS ON MOISTURE BARRIER PROPERTY OF ZEIN FILM

选择合适的增塑剂制备玉米醇溶蛋白膜,并对成膜条件进行优化,改善蛋白膜的阻湿性能。以甘油作为基础增塑剂,研究丙二醇、聚乙二醇、柠檬酸添加量对玉米醇溶蛋白膜性能的影响。结果表明,柠檬酸作为增塑剂制备的玉米醇溶蛋白膜具有较好的机械性能和阻湿性能,当柠檬酸添加量为0.2 g/g时,蛋白膜吸湿率和水蒸气透过率最低。在此基础上,研究了甘油添加量、成膜温度、乙醇体积分数对玉米醇溶蛋白膜阻湿性能的影响。随甘油添加量的增加,膜的吸湿率和水蒸气透过率均逐渐上升,甘油添加量0.1 g/g时最小;随成膜温度的升高,蛋白膜的吸湿率和水蒸气透过率先上升后下降,60℃最小;随乙醇体积分数的增加,蛋白膜吸湿率和水蒸气透过率先下降后上升,乙醇体积分数为70%时最小。采用响应面试验对玉米醇溶蛋白膜的制备条件进行优化,得出当柠檬酸添加量为0.28 g/g、甘油添加量0.11 g/g,成膜温度61.06℃、乙醇体积分数65.04%时,水蒸气透过率最小,为6.28 g·mm·m-2·d-1·k Pa-1。因此,添加柠檬酸可以改善玉米醇溶蛋白膜的阻湿性能。

The suitable plasticizers were chosen to prepare zein film and the film forming conditions were optimized to improve the moisture resistance.For this purpose,glycerin was used as basic plasticizer,and the influences of propylene glycol,polyethylene glycol and citric acid on the mechanical properties and moisture barrier property of zein film were investigated.The result showed that zein film showed better mechanical properties and moisture barrier properties using citric acid as plasticizer,and the membrane moisture absorption rate and water vapor transmission rate were the lowest when citric acid was 0.1 g/g.On this basis of these results,effects of the ratio of glycerol,film forming temperature and ethanol concentration on the rate of moisture absorption and water vapor permeability of zein film were investigated.The results indicated that rate of moisture absorption(RA)and water vapor permeability(WVP)of film gradually increased with the addition of glycerol amount,the minimum value was observed when glycerin was 0.1 g/g;RA and WVP increased firstly and then decreased with the increase of film forming temperature,the minimum was at 60℃;RA and WVP decreased first and then increased with the increase of ethanol concentration,the minimum was at 70%.Response surface methodology was employed to optimize the film preparing conditions,and the result showed that the optimized conditions were as follows:the ratio of citric acid was 0.28 g/g,the ratio of glycerol was 0.11 g/g,the film forming temperature was 61.06℃,and the ethanol concentration was 65.04%.WVP of zein film prepared under these conditions was 6.28 g·mm·m^-2·d^-1-kPa^-1.These results indicated that citric acid could improve the moisture barrier property of zein film.