Valorization of Spondias bahiensis waste: Ultrasound-assisted extraction, in vitro phenolics bioaccessibility, and effect on the stability of lipid-protein oxidation in pre-cooked goat meatballs

This study aimed to optimize the ultrasound-assisted extraction of phenolic compounds from the bagasse of umbu-cajá (Spondias bahiensis), a native Brazilian fruit, and to assess their bioaccessibility. Additionally, the influence of different concentrations of the umbu-cajá bagasse (SBB) extract on the oxidative stability of pre-cooked goat meatballs was investigated over a 10-day refrigerated storage period by quantifying lipid oxidation products. A central composite rotational design determined the optimal ethanol concentration, sonication time, and bagasse-solvent ratio. The optimized extract was applied to meatballs at two concentrations: EX2 (meatballs with 7.0 g/100 g of added SBB extract) and EX4 (meatballs with 13.7 g/100 g of added SBB extract). A control treatment (no antioxidant) and BHT-treated meatballs (0.02 g/100 g) were included as references. Meatballs were evaluated by measuring instrumental color, peroxide value, TBARS, carbonyl compounds, and through simulated digestion. Optimal extraction conditions were 55 % ethanol, 20 min of sonication, and a 1:36.8 bagasse-to-solvent ratio (m/v). The extract showed high antioxidant activity and bioaccessibility of catechin (1243.75 %), epicatechin gallate (918.75 %), procyanidins B2 (915.38 %), gallic acid (319.76 %) and procyanidins B1 (136.36 %). SBB extract slowed lipid oxidation until day 10 and protein oxidation until day 5 but did not inhibit color change. The meatballs had low content of oxidative compounds and high antioxidant capacity in the intestinal fraction, indicating that SBB extract can partially or totally replace the synthetic preservative.