Use of pomegranate peel extract incorporated zein film with improved properties for prolonged shelf life of fresh Himalayan cheese (Kalari/kradi)

Zein films added with different concentrations (0, 25, 50, & 75 mg/ml of film forming solution) of pomegranate peel extract (PPE) were designed and characterized as a novel packaging material for Himalayan cheese (kalari). With increase in PPE concentration, tensile strength, elongation at break, total phenolic content and antioxidant activity of zein films increased whereas film solubility, water vapor transmission rate decreased and thickness remained constant. PPE containing films exhibited inhibitory activity against all tested pathogenic strains (Escherchia coli, Pseudomonas perfringens, Micrococcus luteus, Enterococci faecalis, Staphylococcus aureus, Proteus vulgaris and Salmonella typhii). ATR-FTIR spectra showed interactions between PPE polyphenols and zein film. Kalari wrapped in PPE containing zein films were found to have low protein and lipid oxidation products during storage when compared to film without PPE. Films were also found to inhibit spoilage microorganisms in kalari whereas number of Lactic acid bacteria was enhanced. The study validated that incorporation of fruit waste (pomegranate peel in this case) which are rich in polyphenols, in zein film offers a promising source for inducing it the ability to control cheese spoilage caused either by the bacterial contamination or protein and fat oxidation, without affecting its overall sensory characteristics.