Characterization of the antioxidant potential and bioactive compound content of acerola residue flour (Malpighia emarginata dc.)

Bioactive compounds of plant origin have attracted increasing scientific and industrial interest due to their recognized benefits to human health, particularly their antioxidant capacity, which contributes to the neutralization of free radicals and the prevention of oxidative processes associated with the development of chronic non-communicable diseases. In this context, there is a growing need to identify natural, accessible, and sustainable sources of antioxidant compounds, aligned with the principles of whole food utilization and the reduction of agro-industrial waste. Acerola (Malpighia emarginata DC.) stands out as a fruit of high nutritional value, particularly due to its significant content of vitamin C, phenolic compounds, and carotenoids. However, its industrial processing for pulp, juice, and derivative production generates substantial amounts of waste, mainly composed of peels, seeds, and fibrous fractions, which still retain relevant functional potential. The objective of this study was to evaluate the antioxidant capacity of acerola residue flour using different analytical methods. The flour was produced through drying and grinding of acerola agro-industrial residue. For the extraction of bioactive compounds, grain alcohol was used as the solvent due to its efficiency in extracting phenolic compounds and its applicability in products intended for human consumption. Samples were prepared at a concentration of 100 mg/mL, subjected to ultrasound bath treatment for 10 minutes, and subsequently stored at -80 ºC until analysis. Total phenolic content was determined using the Folin–Ciocalteu method, and total flavonoid content was determined by reaction with NaNO₂, AlCl₃, and NaOH. Antioxidant activity was determined in microplates using the ABTS, DPPH, and FRAP methods, with spectrophotometric readings at 734 nm, 517 nm, and 595 nm, respectively. The results demonstrated a total phenolic content (TPC) of 6.27 ± 0.70 mg GAE/g and a total flavonoid content (TFC) of 3.03 ± 0.31 mg CE/g. Antioxidant capacity was 7.40 ± 0.60 µmol TE/g sample as determined by the ABTS assay, 5.49 ± 0.21 µmol TE/g sample by the FRAP assay, and 79.13 ± 23.05 µmol TE/g sample by the DPPH assay, corresponding to a radical scavenging inhibition of 14.76 ± 6.60. These findings indicate that acerola residue flour possesses relevant antioxidant activity, reinforcing its potential as a sustainable source of bioactive compounds for application in functional foods, dietary supplements, and nutraceutical formulations. Therefore, the valorization of this agro-industrial byproduct contributes to economic value addition, reduction of environmental impacts, and strengthening of sustainable practices based on the circular economy within the food sector.