Fish gelatin films laminated with emulsified gelatin film or poly(lactic) acid film: Properties and their use as bags for storage of fried salmon skin

Abstract

Bilayer films based on fish gelatin films incorporated with epigallocatechin gallate (EGCG) and laminated with poly (lactic acid) film (PLAF) or emulsified gelatin film (EF) were fabricated by thermo-compression molding. Bilayer films showed good handling with low water vapor and oxygen permeabilities. The incorporation of 12 wt % EGCG promoted interactions of gelatin chains, as indicated by improved mechanical and UV–visible light barrier properties. These bilayer films were used for bag making, in which fried salmon skins (FSS) were packaged. After 30 days of storage, FSS packaged in bilayer bags prepared from gelatin films containing EGCG laminated with EF (EF/E-GF) had lower yellowish, peroxide value, thiobarbituric acid reactive substances value and volatile compounds. Overall likeness score as well as linoleic acid (C18:2 n-6) and linolenic acid (C18:3 n-3) contents were also higher than those of FSS packaged in the bags from gelatin films without and with EGCG laminated with PLAF (PLAF/GF and PLAF/E-GF). Therefore, EF/E-GF bilayer films could be used as active packaging for high lipid content foods, especially for fried fish skin, in which lipid oxidation could be retarded.