Antioxidant activities and phenolic compounds of raw and cooked Brazilian pinhão (Araucaria angustifolia) seeds

Abstract

In this study, the antioxidant properties and the polyphenolic contents of raw and cooked pinhao seeds were evaluated. Four methods were used to evaluate the antioxidant activity: 1,1-diphenyl-2-picrylhydrazyl free radical scavenging (DPPH), 2,2’-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid scavenging (ABTS), ferrous ions chelating activity and lipid peroxidation inhibition (LPO). The EC50 values (extract concentration producing 50% antioxidant effect), in μg/ml extract for raw and cooked extracts yielded respectively: DPPH, 870.7±30.8 and 112.6±5.4; ABTS, 170.7±7.8 and 52.1±2.1; ferrous ions chelating activity, 1,719±84.8 and 761±77.1; and LPO, 55.9±4.7 and 53.8±4.5. The improvement in the antioxidant activity in the cooked seeds can be attributed to the migration of polyphenolic compounds from coat to seed during cooking (5.92 ± 0.09 μg/mg and 24.06 ± 1.3 μg/mg in the raw and cooked seed extracts, respectively). Both raw and cooked seeds presented elevated amounts of catechin, 17.49±0.06 and 21.08±0.09 mg/100 g of seed, respectively.   Key words: Antioxidant activity, Araucaria angustifolia, catechin, food processing,pinhao seed, polyphenolics.