Potencial antioxidante de resíduo agroindustrial de goiaba

Abstract

Considering the high production of agri-industrial waste and the possibility of this material have bioactive phytochemicals, this work aimed to evaluate the antioxidant potential of the guava waste (seed) from an industry of frozen fruit pulps. Hydroacetone, hydroethanolic, hydromethanolic and aqueous extracts, obtained by sequential extraction procedure, were submitted to the determination of total phenolic and antioxidant activity in β-carotene/linoleic acid co-oxidation system and by ferric thiocyanate method and screened for their free [DPPH• (1,1-diphenyl-2-picrilhidrazil) and ABTS•+ (2,2'-azino-bis-(3- etilbenzotiazolina 6-sulfonic acid)] scavenging activity. The hydroacetone and hydromethanolic extracts exhibited the highest content of total phenolics (5317.27 and 2176.46 ag catechin equivalent mL-1, respectively), while the aqueous and hydroethanolic extracts were excluded from antioxidant analysis. Hydroacetone extract exhibited high percentage of the inhibition of oxidation (81.95%) in β-carotene/linoleic acid co-oxidation system; high percentage of the inhibition of linoleic acid peroxidation (74.32% and 80.13%at concentrations 140 and 240mg/L, respectively), good DPPH• scavenging activity (scavenging percentage >60%; low value of EC50 and TEC50, middle value of AE), and good ABTS•+ scavenging activity (875.79mM TEAC.g-1). The hydromethanolic extract exhibited low percentage of the inhibition of oxidation (38.92%) in β-carotene/linoleic acid co-oxidation system, inhibition of linoleic acid peroxidation of the 50.50% and 73.70% (at concentrations 140 and 240mg/L, respectively), DPPH• scavenging activity (scavenging percentage < 30%, high EC50 and TEC50, and low value of AE), and bad ABTS• + scavenging activity (57.16 mM TEAC.g -1). Combining of the hydroacetone extract with BHT at different concentrations, the scavenging activity and inhibition of oxidation, in β-carotene/linoleic acid co-oxidation system were similar to that BHT alone, which demonstrated synergism between them. Hydroacetone extract from guava waste (seeds) has a significant potential antioxidant since it has shown better performance in scavenging DPPH • and ABTS• + radical, important antioxidant activity in lipid emulsion system, and synergism with BHT. Thus, the agri-industrial waste from guava can be considered as alternative of natural antioxidants.