Development, properties, and stability of antioxidant shrimp muscle protein films incorporating carotenoid-containing extracts from food by-products

In the present work various waste products from the food industry are intended to be valorized by means of the development of antioxidant edible films. Shrimp muscle proteins, which were extracted from spoiled shrimp due to long freezing storage, were used as a biopolymeric matrix in which lipid extracts obtained from shrimp cephalothorax or tomato peel waste, rich in astaxanthin and lycopene respectively, were incorporated as active ingredients. For comparative purposes a film containing commercial β-carotene was also formulated. The films' properties were determined initially and during storage. Films were transparent and easy to handle, showing high solubility in water (≈90%), and a high water vapor permeability, however, after 30 days of storage (22 °C/50% RH), they became more opaque and less water soluble (≈30%), indicating film matrix reorganizations. UV/Vis spectra, carotenoid content, and color of the films pointed to the occurrence of carotenoid degradation (32, 32, and 17% degradation after one month of storage for β-carotene, lycopene, and astaxanthin, respectively), as well as a hint of interaction of lycopene with the protein network. Antioxidant activity was very stable during storage, in spite of the carotenoid degradation, suggesting that other compounds present in the extracts contributed to the antioxidant activity.The authors wish to thank the Spanish Ministry of Economy and Competitiveness for financial support through project AGL2011-27607Peer Reviewe