The PVPP-WS extract displays a higher degree of radical scavenging activity than rosemary extract and BHT, a synthetic antioxidant commonly used in the food industry.
Natural extracts proved to be effective antioxidants and reduced lipid oxidation when added directly to the surface of refrigerated beef samples and therefore the direct contact with foodstuff is mandatory to obtain a significant reduction in lipid oxidation of beef samples. Therefore, it may be possible to use these natural extracts to replace synthetic antioxidants in food. The PVPP-WS extract displays a similar antioxidant effect to PG in reducing lipid oxidation, and was more effective than BHT and rosemary extract. Active films containing natural extracts were successfully produced, and the use of these active films coated with natural antioxidants enhanced oxidative stability of beef relative to that obtained with the film control during cold storage. The best results were obtained with the extract obtained from the brewery residual stream (PVPP-WS), which reduced lipid oxidation by up to 90%. These active films appear promising for the development of active antioxidant packaging for use with meat products.