普鲁兰酶改性SNC/ZnO增强的马铃薯复合膜的制备

Preparation of Enhanced SNC/ZnO Potato Composite Film Modified by Pullulanase

摘要:

以马铃薯淀粉为原料，以生物法对淀粉进行改性，普鲁兰酶可以专一性切开支链淀粉分支的α-1,6糖苷键提高直链淀粉含量，从而提高淀粉膜性能，同时以尿尿素为增塑剂，淀粉纳米晶（SNC）与纳米氧化锌(ZnO)为复合增强剂，采用流延法制备复合膜。以单因素试实验验 研究考察了增塑剂种类及用量、增强剂种类及用量对复合膜性能的影响。普鲁兰酶可以专一性切开支链淀粉分支的α-1,6糖苷键提高直链淀粉含量，从而提高淀粉膜性能。 以利用正交实验试验法探究淀粉酶解工艺，以复合膜的拉伸强度为指标，得到马铃薯淀粉的最佳酶解工艺为：酶用量0.8U/g，反应温度50℃，pHpH 4.0，反应时间2h。与未经酶处理的复合膜相比，马铃薯淀粉复合膜拉伸强度增加19%，断裂伸长率增加42.8%，透明度增加5.6%，雾度下降67.4%，水蒸气透过系数下降98.4%，透油系数下降52.6%。

Abstract:

Using potato starch as raw material, the starch was modified by biological method. Pullulanase can spe-cifically cut the α-1,6 glycosidic bond of the starch branch to increase the amylose content, thereby im-proving the performance of the starch film. Using Urea as plasticizer, starch nanocrystal (SNC) and nano zinc oxide (ZnO) as composite reinforcing agents, the composite film is prepared by casting method. The effects of the type and amount of plasticizer and the type and amount of reinforcing agent on the proper-ties of the composite membrane were investigated by single factor experiments. The amylolytic process was explored by orthogonal experiment. The optimal enzymatic hydrolysis process of potato starch was obtained by using the tensile strength of the composite membrane as the index: enzyme dosage 0.8U/g, reaction temperature 50 °C, pH 4.0, reaction time 2h. Compared with the non-enzymatic composite membrane, the tensile strength of potato starch composite film increased by 19%, the elongation at break increased by 42.8%, the transparency increased by 5.6%, the haze decreased by 67.4%, and the water vapor transmission coefficient decreased by 98.4%, Oil permeability coefficient decreased by 52.6%.