Physical and functional properties of pectin-fish gelatin films containing the olive phenols hydroxytyrosol and 3,4-dihydroxyphenylglycol

Abstract

This study describes the development of a composite edible film based on pectin and fish skin protein capable of protecting food from microbial attack and oxidative degradation. The film was prepared with glycerol as plasticizer and the antioxidant and antimicrobial phenolic compounds hydroxytyrosol (HT) and 3,4-dihydroxyphenylglycol (DHPG), extracted from olive fruit, as active agents. The influence of the concentration of plasticizer and active HT/DHPG on the mechanical and functional properties of the films was investigated, with values of water vapor permeability (WVP) between 0.13-0.22gmm/hm²kPa and oxygen permeability (OP) between 9.91-40.76cm³μm/m²dkPa. The release behavior in water at different pH values was also evaluated. The antimicrobial capacity of the novel food coating was tested on strawberries, a fruit with high perishability. The bioactive edible film containing HT/DHPG preserved the strawberries against mold during storage with a significant delay in visible decay.

Keywords: Composite films; Edible coating; Pectin; Phenolic compounds; Skin fish protein; Strawberries.