Effect of oxidized phenolic compounds on cross-linking and properties of biodegradable active packaging film composed of turmeric and gelatin

Abstract

Cross-linking effects of different phenolic substances (tannic acid, caffeic acid, and green tea extract) on mechanical and barrier properties of biodegradable films consisting of turmeric (Curcuma tonga) and gelatin were investigated. The results showed that degree of protein cross-linking increased with concentration of oxidized phenolic compounds, resulting in denser and stiffer film structures. Cross-link formation led to higher tensile strength and lower elongation-at-break (%), water vapor permeability, and water solubility of films with formation of aggregations. However, at high concentrations of phenolic compounds, molecular mobility increased due to grafting/branching reactions resulting in plasticizing effect. The developed films were applied as active packaging materials to fresh ground pork to extend shelf life, demonstrating good antioxidant activity and preventing lipid oxidation of fresh pork. No significant difference (p > 0.05) was noted in the overall acceptability of all samples by sensory analysis.