Vol.:(0123456789) 1 3 European Food Research and Technology https://doi.org/10.1007/s00217-020-03571-3 ORIGINAL PAPER Industrial multi‑fruits juices by‑products: total antioxidant capacity and phenolics profile by LC–MS/MS to ascertain their reuse potential Mariana A. Andrade 1,2,3  · Lucíllia Rabelo de Oliveira Torres 4,5  · Ana Sanches Silva 6,7  · Cássia H. Barbosa 1  · Fernanda Vilarinho 1  · Fernando Ramos 2,3  · Ana Rodriguez Bernaldo de Quirós 4  · Khaoula Khwaldia 7,8  · Raquel Sendón 4 Received: 22 March 2020 / Revised: 7 July 2020 / Accepted: 12 July 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract 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 anti- oxidant 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. Keywords Industrial fruits by-products · Antioxidant capacity · Phenolic compounds · HPLC–DAD · HPLC–MS/MS · Active food packaging · Ethanolic extracts Mariana A. Andrade and Lucíllia Rabelo de Oliveira Torres have contributed equally for this work. * Fernando Ramos ramos@ci.uc.pt; framos@ff.uc.pt 1 Department of Food and Nutrition, National Health Institute Dr Ricardo Jorge (INSA), I.P., Av. Padre Cruz, 1649-016 Lisbon, Portugal 2 Faculty of Pharmacy, University of Coimbra, Azinhaga de Santa Comba, 3000-548 Coimbra, Portugal 3 REQUIMTE/LAQV, R. D. Manuel II, Apartado, 55142 Oporto, Portugal 4 Department of Analytical Chemistry, Nutrition and Bromatology, Pharmacy Faculty, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain 5 Maranhão Federal Institute of Education, Science and Technology, Caxias, Maranhão 65609899, Brazil 6 National Institute for Agricultural and Veterinary Research (INIAV), Vairão, Vila do Conde, Portugal 7 Center for Study in Animal Science (CECA), ICETA, University of Porto, Porto, Portugal 8 Laboratoire des Substances Naturelles, Institut National de Recherche et d’Analyse Physico-Chimique, INRAP, Pôle Technologique de Sidi Thabet, 2020 Sidi Thabet, Tunisia