Active PHBV films with ferulic acid or rice straw extracts for food preservation

Abstract

Developing of more sustainable food packaging solutions are necessary to better preserve foods while reducing the environmental impact of non-degradable plastics. To this end, active and biodegradable PHBV films were obtained by incorporating 6 % by weight of ferulic acid (FA) or phenol-rich aqueous extracts obtained from rice straw produced at 160 °C (RSE160) and 180 °C (RSE180), under subcritical conditions. These films, prepared by melt blending and compression moulding, showed a high barrier capacity to oxygen and water vapour, and a high UV light blocking effect. The antibacterial action against gram-positive (L. innocua) and gram-negative (E. coli) bacteria in different culture media or food matrices (TSA, fresh salmon and pumpkin) was tested in in-vitro assays. The inhibition of bacterial growth depended on the active component, the culture medium and the type of bacteria. Films containing FA (1.7 log CFU reduction of E. coli and 1.0 log CFU of L. innocua in pumpkin) or RSE180 (1.3 log CFU reduction of E. coli in TSA and 1.1 log CFU of L. innocua in salmon) were the most active and were chosen for producing pouches and packaging pork. The preservation capacity of pork in packaged samples was analysed throughout cold storage (4 °C, 16 days). Both active films reduced bacterial counts and meat oxidation levels, prolonging the shelf life of the meat by 4 (RSE) to 8 (FA) days compared to the control films (PHBV without actives and LDPE). Therefore, this study developed novel biodegradable food packaging capable of extending the shelf life of various foods, including pumpkin, salmon, and pork.