The effect of roasting on the phenolic compounds and antioxidant potential of baru nuts [Dipteryx alata Vog.]

The effect of roasting on phenolic compounds and antioxidant activities in baru nuts (Dipteryx alata Vog) with and without peels were investigated. Approximately 50% of the total phenolic content (Folin Ciocalteu assay) and 90% of the free radical-scavenging activity (DPPH) were present in the peel of the baru nut. Among the eight phenolics identified: p-coumaric acid, ellagic acid, caffeic acid, hydroxybenzoic, catechin, ferulic acid, epicatechin and gallic acid, the last was predominant in all nut samples with values that ranged from 224.0 to 66.7 mg/100 g. The roasting process did not reduce the total phenolic content significantly compared to the raw nut (p > 0.05). However, roasting reduced the DPPH activity by approximately 50% in the nuts with peels. With the exception of gallic acid, the content of the other seven phenolic compounds significantly decreased after the roasting process in baru nuts with peels, suggesting that a phenolic other than gallic acid is the main compound responsible for the antioxidant potential of this nut.