壳聚糖分子质量对原位改性纳米CaCO3-壳聚糖涂膜食品保鲜性能的影响

Effects of Chitosan’s Molecular Weight on the Food Preservation Properties of the in-Situ Modified Nano CaCO3-Chitosan Coatings

为研究壳聚糖分子质量对原位改性纳米CaCO3-壳聚糖复合涂膜食品保鲜性能的影响,以不同分子质量壳聚糖为基材,采用流延法制备复合涂膜,并对其进行SEM,TEM,XRD,FT-IR表征分析和理化性能测定。以美国红鱼为保鲜对象,测定该膜的保鲜性能。结果表明,壳聚糖分子质量为60 kU时,原位改性纳米CaCO3粒子间有团聚现象。壳聚糖分子质量为100 kU时,原位改性纳米CaCO3粒子在涂膜中分散不均,有团聚现象,且涂膜断面不平整,有裂纹和气孔。而壳聚糖分子质量为160 kU时,复合涂膜中纳米粒子粒径均匀且大小合适,分散均匀,基本无团聚现象,与壳聚糖相容性好,且理化性能更优。与空白组和壳聚糖分子质量为60 kU的复合涂膜处理的美国红鱼相比,经壳聚糖分子质量160 kU的复合涂膜处理的美国红鱼的鲜度指标和质构指标下降缓慢,可有效保持美国红鱼优良的品质,延长货架期。

In order to study the effect of molecular weight of chitosan on the food preservation performance of in-situ modified nano CaCO3-chitosan composite coatings,the composite coatings of chitosan with different molecular weight were prepared by tape casting,the characterization of SEM,TEM,XRD,and FT-IR were analysed,the physicochemical properties were determinated,and the preservation performance of composite coatings were determinated using Sciaenops ocellatus as freshness object.The results showed that the phenomenon of agglomeration ccould be formed in the in-situ modified nano CaCO3 particles when the molecular weight of chitosans was 60 kU.The molecular weight of chitosan was 100 kU,which results in uneven dispersion and agglomeration in in-situ modified nano CaCO3 particles in the coating,moreover,the section of coating was not smooth and there were cracks and pores.When the molecular weight of chitosan was 160 kU,the size of the nanoparticles in composite coating was even and suitable,evenly dispersed,basically no agglomerative,and good compatible with chitosan,and which physical and chemical properties were better.Compared Sciaenops ocellatus which were untreated and the chitosan molecular weight of 60 kU composite coating,the freshness index and structure index of Sciaenops ocellatus which were treated with the chitosan molecular weight of 160 kU composite coating were slowly down.That indicated it could effectively ensure the quality of Sciaenops ocellatus and prolong the shelf life.