Production, characteristics and application of whey protein films activated with rosemary and sage extract in preserving soft cheese

Active packaging can be utilized to keep away from undesirable microbes on the surface of the cheese, prolong its shelf life, and improve its quality. The objective of this study was to use whey protein concentrate (WPC) and aqueous rosemary and sage extracts to produce active edible packaging materials. The antioxidant activity of the extracts was evaluated along with their total phenolic and flavonoid contents. LC/DAD/ESI-MSn analysis was used for the qualitative characterization of extracts and their main compounds were quantified using HPLC methods. Films were characterized according to their physicochemical and tensile properties. They were applied for coating soft cheese surfaces stored 60 days of cold storage at 4 °C. Both infusions showed almost similar antioxidant activity, although differences were detected in their total phenolic and flavonoid contents. Their phytochemical analysis revealed the presence of polyphenols. No significant differences in film thickness and moisture content were detected among the films. The presence of rosemary infusion did not significantly influence the mechanical properties of the films; while, sage infusion reinforced films compared to the control film. In the cheese samples coated with edible films fortified with infusions no spoilage or pathogenic bacteria appeared until the end of storage days.