Biodegradable and antioxidant films with barrier properties to visible and ultraviolet light using Hass avocado (Persea americana Mill.) by-products

The search for renewable sources that can be used to develop products as alternatives to traditional polymers in the future, without affecting food safety, represents a challenge for the food industry. In this context, agro-industrial waste has emerged as an interesting alternative. This study evaluated biodegradable films made from Hass avocado seed flour without (Control film; PC) and with antioxidant extracts (PExBIO and PExIND) derived from the epicarp of the same fruit. The results showed that all the films blocked visible (over 96 %) and ultraviolet light (99.9 %), which was mainly attributed to perseorangine, a compound generated by the action of polyphenol-oxidase. The films also exhibited good water vapor barrier properties. PExIND showed the highest mechanical strength (Young's modulus = 901.8 ± 33.4 MPa; tensile strength = 9.1 ± 1.0 MPa; elongation = 3.5 ± 0.5 %), correlating with the highest crystallinity index (14.9 %). The incorporation of extracts increased the content of phenolic compounds and antioxidant capacity in PExBIO and PExIND compared to PC, with no significant differences between them. Moreover, the biodegradation test indicated that the films showed high biodegradability. Therefore, Hass avocado residues could be used to produce biodegradable antioxidant films, suitable for packaging light-sensitive and low-moisture products.