Investigating bioactive compounds in apple pomace: Potential to develop high added-value products from an industrial surplus

This study investigates bioactive compounds in apple pomace (AP) obtained from Malus domestica varieties Granny Smith and Cripps Pink, emphasizing its potential for developing high-added-value products from industrial surplus. Regarding its chemical characterization, AP stood out for its high concentration of dietary fibers (7.1g/100g fw), polyunsaturated fatty acids (linoleic and oleic acids), alpha-tocopherol (0.64 mg/100g fw), and phenolic compounds. Regarding these last, the profile obtained by HPLC-DAD-ESI/MS allowed the identification of 23 phenolic compounds, with higher concentrations of quercetin and flavonoids in pomace than whole apples. Moreover, concerning evaluating AP bioactivity through in vitro methods, the analyzed AP samples, with seeds and stems (APSS) and without (APA), exhibited enhanced antioxidant activity, particularly in the OxHLIA test, preserving erythrocyte integrity. Additionally, the pomace demonstrated significant antibacterial activity against Yersinia enterocolitica, Staphylococcus aureus, and Escherichia coli, with a minimum inhibitory concentration of 5 mg/mL. Finally, no cytotoxic or anti-inflammatory effects were observed, as GI50 values exceeded 400 mu g/mL (maximum tested concentration). These findings highlight apple pomace as a rich source of bioactive compounds, promoting its valorization in food safety and preservation while encouraging sustainable practices utilizing industrial bio-residues.