Phupoksakul Thunyaluck, Leuangsukrerk Manusawee, Numpiboonmarn Pidsawat, Somwangthanaroj Anongnat, Janjarasskul Theeranun
Department of Food Technology, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand.
J Sci Food Agric. 2015 Mar 15;95(4):715-21. doi: 10.1002/jsfa.6775. Epub 2014 Jul 10.
This study aims to examine the feasibility of a novel multi-layer barrier film made entirely from biopolymers, which can be disposed after use in an economically and ecologically acceptable way, by employing mechanical strength and moisture barrier of poly(lactide) (PLA) films and oxygen barrier enhancement of whey protein isolate (WPI) films. The effect of glycerol was also determined. The three-layer films, PLA/WPI/PLA, were compared with those made of linear low-density polyethylene films (LLDPE/WPI/LLDPE). Composite structures of three-layer films obtained by a simple casting method using denatured WPI solution plasticised with glycerol (GLY) at three different ratios of GLY:WPI (1:4, 1:2.5 and 1:1.5). The WPI solution was applied between two base layers of corona-treated PLA or LLDPE films.
The multi-layer films showed good appearance with no noticeably visible change and good adhesion of layers. PLA enhanced tensile strength of the composite structure. Oxygen permeability of the multi-layer films was significantly lower than the base films. The water vapour permeability of the structure relied mainly on the base films. The plasticiser content did not significantly affect the properties of the multi-layer structures.
Results suggested that WPI could work successfully as an alternative oxygen barrier layer of multi-layer structures.
本研究旨在通过利用聚乳酸（PLA）薄膜的机械强度和防潮性以及乳清蛋白分离物（WPI）薄膜的氧气阻隔增强作用，研究一种完全由生物聚合物制成的新型多层阻隔薄膜在使用后以经济和生态可接受的方式进行处置的可行性。还测定了甘油的作用。将三层薄膜PLA/WPI/PLA与由线性低密度聚乙烯薄膜（LLDPE/WPI/LLDPE）制成的薄膜进行比较。通过简单的流延法，使用甘油（GLY）以三种不同比例（1:4、1:2.5和1:1.5）增塑的变性WPI溶液获得三层薄膜的复合结构。将WPI溶液涂覆在经电晕处理的PLA或LLDPE薄膜的两个基层之间。
多层薄膜外观良好，无明显可见变化，层间附着力良好。PLA提高了复合结构的拉伸强度。多层薄膜的氧气透过率明显低于基层薄膜。该结构的水蒸气透过率主要取决于基层薄膜。增塑剂含量对多层结构的性能没有显著影响。
结果表明，WPI可以成功地作为多层结构的替代氧气阻隔层。
