Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710, USA.
J Agric Food Chem. 2010 Mar 24;58(6):3753-60. doi: 10.1021/jf9033128.
It has been stated that hydroxypropyl methyl cellulose (HPMC) based films have promising applications in the food industry because of their environmental appeal, low cost, flexibility and transparency. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of this work was to enhance these properties by reinforcing the films with microcrystalline cellulose (MCC) at the nano scale level. Three sizes of MCC nanoparticles were incorporated into HPMC edible films at different concentrations. Identical MCC nanoparticles were lipid coated (LC) prior to casting into HPMC/LC-MCC composite films. The films were examined for mechanical and moisture barrier properties verifying how the addition of cellulose nanoparticles affected the water affinities (water adsorption/desorption isotherms) and the diffusion coefficients. The expected reinforcing effect of the MCC was observed: HPMC/MCC and HPMC/LC-MCC films showed up to 53% and 48% increase, respectively, in tensile strength values in comparison with unfilled HPMC films. Furthermore, addition of unmodified MCC nanoparticles reduced the moisture permeability up to 40% and use of LC-MCC reduced this value up to 50%. Water vapor permeability was mainly influenced by the differences in water solubility of different composite films since, in spite of the increase in water diffusivity values with the incorporation of MCC to HPMC films, better moisture barrier properties were achieved for HPMC/MCC and HPMC/LC-MCC composite films than for HPMC films.
有人指出，羟丙基甲基纤维素（HPMC）基薄膜由于其环境吸引力、低成本、灵活性和透明度，在食品工业中有很有前途的应用。然而，它们的机械和防潮性能应该得到改善。这项工作的目的是通过在纳米尺度上用微晶纤维素（MCC）增强薄膜来提高这些性能。将三种尺寸的 MCC 纳米颗粒以不同的浓度掺入 HPMC 可食用薄膜中。相同的 MCC 纳米颗粒在铸造成 HPMC/LC-MCC 复合薄膜之前被脂质包覆（LC）。对这些薄膜进行机械性能和防潮性能测试，验证纤维素纳米颗粒的添加如何影响水亲和力（水分吸附/解吸等温线）和扩散系数。观察到 MCC 的预期增强效果：与未填充的 HPMC 薄膜相比，HPMC/MCC 和 HPMC/LC-MCC 薄膜的拉伸强度值分别提高了 53%和 48%。此外，添加未改性的 MCC 纳米颗粒可将透湿性降低高达 40%，而使用 LC-MCC 可将该值降低高达 50%。水蒸气透过率主要受不同复合薄膜的水分溶解度差异的影响，因为尽管将 MCC 掺入 HPMC 薄膜会增加水扩散系数，但对于 HPMC/MCC 和 HPMC/LC-MCC 复合薄膜而言，其防潮性能优于 HPMC 薄膜。
