Characterization and effect of edible alginate acidified coatings associated with photodynamics on cheese preservation

Abstract

The use of edible coating is an option to improve food quality and increase product shelf life. Photodynamic therapy and acid addition may be another option which decreases the number of viable microorganism cells, including Gram-negative bacteria. The present work aimed to evaluate the application of edible coatings that have the ability to inhibit the growth of Escherichia coli, using acidic pH and photodynamic therapy, in order to increase shelf life of fresh cheese. Coatings were prepared with the addition of lactic, malic and citric acids. The control coating micrograph showed surface stains, and crystal formation was apparently accentuated by the presence of citric and malic acid, not observed in the control coating or lactic acid coating. The surface micrograph of the lactic acid alginate coating showed greater homogeneity without stains and cracks. The addition of citric acid to the coating was the best result for in vitro bacterial survival tests and was therefore chosen, this coating decreased microbiological counts in the first 7 days with smaller weight loss, controlled acidity and pH and lipid oxidation remained as expected.

Keywords

• Biodegradable films
• Escherichia coli
• Active packaging
• Shelf life