Phenolic composition, antioxidant capacity and volatile compounds of licuri (Syagrus coronata (Martius) Beccari) fruits as affected by the traditional roasting process

This work is a contribution to knowledge of the phenolic composition, antioxidant capacity and volatile profile of licuri (Syagrus coronata (Martius) Beccari) fruits. Samples of raw and roasted licuri were provided by an agricultural cooperative in the state of Bahia (Brazil). The phenolic composition was both estimated by spectrophotometric assays (by measuring the content of total phenolics, total flavonoids, and condensed tannins) and quantified by HPLC-MS. Antioxidant capacity was evaluated by ABTS and DPPH radical scavenging assays, while volatiles were determined by HS-SPME-GC/MS. An increase of total phenolics, total flavonoids and total condensed tannins was observed after the roasting process. Similarly, the antioxidant capacity of roasted seeds was higher than that of raw samples. Among phenolic compounds (+)-catechin, (-)-epicatechin, procyanidins B1 and B2, myricetin, quercetin, quercetin-3-O-glucoside, quercetin-3-O-rhamnoside, quercetin-3-O-rutinoside and luteolin were identified. The majority of these phenolics significantly increased during the roasting process. Among volatiles, carboxylic acids such as octanoic and hexanoic acids prevailed in raw licuri seeds. However, after roasting, these compounds decreased and Strecker aldehydes, δ-lactones and alkyl pyrazines, (all with high odor activity), became the most abundant.