Industrial multi-fruits juices by-products: total antioxidant capacity and phenolics profile by LC–MS/MS to ascertain their reuse potential

Many food formulations use fruits as their main component generating, in most cases, a large portion of fruits by-products which are generally considered as food waste. These by-products, due to its varied composition of active compounds, must be discarded in a responsible and ecological manner by the food industries, which can increase the final cost of the food formulation. The compounds present in this by-products can be useful to the food industry due to their antioxidant and antimicrobial activities and, its reuse is important to establish a circular economy in the food industry. In this study, the antioxidant potential of ethanolic extracts of fruit by-products was evaluated. Also, the principal phenolic compounds of these by-products were determined by HPLC–DAD and HPLC–ESI–MS/MS. The formulation 1 (F1) of juice by-products was composed by the by-products of the juice prepared with ginger and apple (50:50, w/w) and the formulation 2 (F2) of juice by-products was made up of the by-products of the juice prepared with apple, carrot, beet and ginger (50:29:20:1, w/w). The extracts obtained from the freeze-dried by-products presented higher antioxidant capacity and higher amounts of phenolic compounds, namely flavonoids, that the extracts obtained from the fresh by-products. Also, the extracts obtained from F1 presented a higher antioxidant capacity than the extracts from F2, mostly due to its high content in ginger. The obtained results from the different assays are in agreement among them and indicate that the F1 extract is the most suitable candidate to be applied to food applications and, active food packaging due to its high antioxidant capacity.