多糖基膜内抑菌剂向食品模拟体系中释放的规律

Release Model of Antimicrobial Agent from Polysaccharide-based Film into Food Stimulant

摘要:

本文研究多糖基抑菌膜（低甲氧基果胶-羧甲基纤维素-山梨酸钾（LMP-CMC-Psb，LCP））内抑菌剂Psb在4℃下的释放动力学。分别探讨了基膜比例LMP:CMC（8:2、6:4、4:6）、CaCl2（1%、2%、4%、8%）、蒙脱土（MMT，1%、4%、8%、12%）及Psb（2%、5%、8%、15%）含量变化对Psb向食品模拟液（50%乙醇）中释放的影响；并使用Fickian第二定律方程和简化模型与Psb释放试验数据进行非线性最小二乘法拟合，计算得出扩散系数，进而评估Psb的扩散能力。结果表明：通过调整膜基质LMP和CMC的比例、改变CaCl2、MMT在基膜内的浓度可有效地控制Psb的释放速率；提高LMP比例、CaCl2和MMT含量均可降低Psb的扩散系数。通过Fickian第二定律拟合结果证实了Fickian模型与Psb的释放有很好的拟合度（R2>0.98%），说明该拟合具有一定可靠性，可以用来模拟Psb的释放。本文亦发现可通过使用简化模型对Psb的短期释放进行拟合而得的扩散系数评估Psb在抑菌膜内的释放规律，以缩短试验时间。该抑菌材料有望作为可控释放包装体系用于包装食品。

Abstract:

Low methoxyl pectin–carboxymethyl cellulose (LMP-CMC) composite films carrying potassium sorbate (LCP films) were prepared to study the release kinetics of Psb into food stimulant (50% ethanol). The release of Psb from LCP ?lms with three ratios of LMP:CMC (8:2, 6:4, and 4:6) was studied at 4?C. The release of Psb from LCP films (4:6) with different contents of calcium chloride (1%, 2%, 4%, and 8%), MMT (1%, 4%, 8%, and 12%) and Psb (2%, 5%, 8%, 15%) at 4 ℃ was also investigated. The release kinetics of Psb was described using the Fickian second law of diffusion and a simple model. The diffusion coef?cient was determined by fitting the experimental data of Psb released to models to estimate diffusivity of Psb by nonlinear least square method. The results clearly demonstrated that the release of Psb from LCP films can be tailored by changing the composition of the initial casting solution, the content of calcium chloride and MMT. The increased LMP, calcium chloride, and MMT levels resulted in a reduction of diffusion coefficients of Psb. The Fickian model satisfactorily described the experimental data, suggesting that the release kinetic of Psb can be described through the model (R2 >0.98%), and the method of calculating diffusion coef?cient from Fickian second law was reliable. The simple model can be used to describe Psb released for short contact times, to shorten the testing time; the model was satisfactory to determine the diffusion coefficients of Psb. The results indicated that the LCP film has a good potential to achieve a controlled release in antimicrobial packaging.