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Phenolic compounds and carotenoids profile of Amazonian Eryngium foetidum leaves and the quenching ability of their hydrophilic extract against singlet oxygen (1O2) were determined. Chlorogenic acid (4327 μg/g, dry basis, d.b.) was the major phenolic compound in the leaves at very high concentrations, while lutein (205 μg/g, d.b.) and β-carotene (161 μg/g, d.b.) were the major carotenoids. The extract of E. foetidum leaves was able to scavenge DPPH● (91.6% at 5 mg/mL), ABTS●+ (15.77 μM Trolox equivalent/g extract) and it exhibited high efficiency to protect tryptophan against 1O2, with IC50 at 343 μg/mL and 78% of protection at the highest tested concentration (625 μg/mL). Therefore, E. foetidum leaves can be exploited as an accessible natural source of bioactive compounds with antioxidant properties to be used by the food or pharmaceutical industries.

Antrocaryon amazonicum fruits are unexploited sources of bioactive compounds found in the Amazonia region of Brazil. In this study, for the first time, the carotenoid and phenolic compound profiles of the pulp and peel of A. amazonicum fruits, from two varieties at two harvest periods, were determined by LC-MS. Additionally, the potential of the peel and pulp extracts to scavenge physiologically relevant reactive oxygen species (ROS) and reactive nitrogen species (RNS) was assessed. The major carotenoids in both parts of the fruits were lutein, accounting for ≈42% of the identified carotenoids in the peel and ≈25% in the pulp, whereas catechin and hydroxybenzoic acid derivatives were the major phenolics in both parts. The peel extract, which presented the highest bioactive compound contents, was more efficient to scavenge ROS than the pulp. The peel extract showed high scavenging efficiency (IC50 ) for singlet oxygen (1 O2 ; 16 µg/ml), hypochlorous acid (HOCl; 20 µg/ml), peroxynitrite (ONOO- ; 38 µg/ml), and superoxide radical (O2•- ; 47 µg/ml), whereas the pulp extract exhibited high efficiency for ONOO- (13 µg/ml), followed by HOCl (30 µg/ml), ¹O2 (76 µg/ml), and less efficient for O2•- (44 µg/ml). Therefore, A. amazonicum fruits can be seen as an expressive source of bioactive compounds with high antioxidant potential to be further investigated to inhibit or delay oxidative processes both in food and physiological systems triggered by ROS and RNS. PRACTICAL APPLICATION: Bioactive compound extracts of Antrocaryon amazonicum fruits have high potential to be exploited for inhibiting or delaying oxidative processes and increase food stability.

Arrabidaea chica (Brazilian name = pariri) is a plant species that belongs to the Bignoniaceae family, occurring in tropical America and widespread in the Amazonian region of Brazil. In this study, the phenolic compound and carotenoid profiles of A. chica leaves were determined by HPLC-DAD-MS. Scutellarin was identified as the main phenolic compound (15,147.22 μg/g, dry basis, d.b.) and lutein (204.28 μg/g, d.b.), β-carotene (129.5 μg/g, d.b.) and α-carotene (79.86 μg/g, d.b.) as the major carotenoids. Moreover, A. chica leaves presented 152.7 μg/g of ascorbic acid (fresh weight). For the first time, the carotenoid profile and ascorbic acid contents were reported for A. chica leaves. Regarding the antioxidant capacity, A. chica extract was able to scavenge ABTS radical (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)), and for the first time, the protective effect against singlet oxygen (1O2) was reported. The A. chica extract was efficient as ABTS radical scavenger (86.81 μM Trolox/g of fresh leaves) and inhibited the degradation of tryptophan by 1O2 in a concentration-dependent manner with an IC50 at 177 μg/mL. Thus, A. chica leaves can be exploited as a promising source of bioactive compounds that may be useful to human health or food systems against oxidative damage.

This study aimed to identify the volatile compounds in the fermented and dried cocoa beans conducted with three distinct inoculants of yeast species due to their high fermentative capacity: Saccharomyces cerevisiae, Pichia kudriavzevii, the mixture in equal proportions 1:1 of both species, and a control fermentation (with no inoculum application). Three starter cultures of yeasts, previously isolated and identified in cocoa fermentation in the municipality of Tomé-Açu, Pará state, Brazil. The seeds with pulp were removed manually and placed in wooden boxes for the fermentation process that lasted from 6 to 7 days. On the last day of fermentation, the almonds were packaged properly and placed to dry (36 °C), followed by preparation for the analysis of volatile compounds by GC-MS technique. In addition to the control fermentation, a high capacity for the formation of desirable compounds in chocolate by the inoculants with P. kudriavzevii was observed, which was confirmed through multivariate analyses, classifying these almonds with the highest content of aldehydes, esters, ketones and alcohols and low concentration of off-flavours. We conclude that the addition of mixed culture starter can be an excellent alternative for cocoa producers, suggesting obtaining cocoa beans with desirable characteristics for chocolate production, as well as creating a product identity for the producing region.