Preparation and Characterization of Antioxidative and UV-Protective Larch Bark Tannin/PVA Composite Membranes

摘要

In order to prepare functional materials for antioxidant and ultraviolet (UV)-protectivegreen food packaging, condensed tannin, previously extracted from larch bark, was mixedwith polyvinyl alcohol (PVA), and then the mixture was used to cast composite membranes.An antioxidative assay using 1,1-diphenyl-2-picrylhydrazyl (DPPH)—a free radical scavenger—andstarch–potassium iodide oxidation–discoloration analyses showed that the composite membraneshave good antioxidative activities. The low UV transmission and protective effect of the compositefilms on vitamin E indicated the UV protection ability of the composite membranes. Both larch barktannin and PVA are rich in hydroxyl groups; scanning electron microscopy analysis demonstratedtheir compatibility. Also, the mechanical and crystallization properties of the composite membranesdid not significantly decrease with the addition of larch bark tannin.