Smart film based on chitosan/Melissa officinalis essences/ pomegranate peel extract to detect cream cheeses spoilage

Antibacterial/biodegradable film based on Chitosan (CS)/pomegranate peel extract (PPE) and Melissa officinalis Essences (MOE) was prepared. To study the effects of PPE and MOE on the film characteristics, a central composite design (CCD) was used. The physicochemical characteristics of the film, including moisture, water vapour permeability (WVP), antioxidant activity, microbial properties, FT-IR/SEM/XRED spectrum, etc. were studied. The results showed that the addition of PPE significantly reduced the amount of moisture loss. The WVP increased with the addition of MOE and decreased with the addition of PPE. MOE and PPE increased the antioxidant activity of the films. In terms of microbial properties, the antimicrobial effect of MOE on B. cereus was greater than on E. coli. The results of SEM showed that the PPE particles were uniformly distributed in the film matrix and the MOE slightly reduced the surface compression of the film. The CS/PPE/MOE film was used for smart packaging of cream cheese and detection of cheese spoilage. It was observed that with increasing storage time and storage temperature, with regard to the change in the pH of the cream cheese, samples become acidic. The PPE contains anthocyanin pigments that are sensitive to pH changes so the film colour was changed (from blue to red) during storage. The colour change of the film was visible with the naked eye and can be used to estimate the expiry date of the cheese.