Poliana S. Epaminondas

Refining of buriti oil (Mauritia flexuosa) originated from the Brazilian cerrado: physicochemical, thermal-oxidative and nutritional implications.

The objective of this study was to compare the physicochemical, thermo-oxidative and nutritional characteristics of crude and refined buriti oil. Crude and refined oil samples were evaluated for viscosity, relative density, refraction, acidity, free fatty acids, peroxide and iodine, lipid oxidation degree by UV-Vis, thermogravimetry, calorimetry, in vitro antioxidant capacity, vitamin A content and fatty acids profile. The refining process decreased the free fatty acids percentage and acidity, peroxide and iodine indexes, with greater thermal-oxidative stability, which is critical for its use in cooking food. However, its antioxidant capacity, vitamin A and unsaturated fatty acids contents were reduced compared to crude oil. Therefore, it is suggested to optimize the refining process to minimize nutritional losses in buriti oil, which due to its characteristics, can be considered a functional food.

Antioxidant activity of co-products from guava, mango and barbados cherry produced in the Brazilian northeast.

Co-products from the juice processing of guava (CG), mango (CM) and barbados cherry (CB) were investigated with a view to their exploitation as a potential source of natural antioxidants. The ethanolic extracts were analyzed for total extractable phenolic content (TEP), DPPH radical scavenging activity (RSA-DPPH), ferric reducing antioxidant power (FRAP) and antioxidant activity in relation to the β-carotene/linoleic acid system. The TEP levels in the CG, CM and CB extracts were (24.15 ± 1.59), (44.18 ± 1.73) and (49.21 ± 3.70) mg GAE/g extract, respectively. The CM extract showed higher DPPH, FRAP and antioxidant activity in the β-carotene/linoleic acid system. The data revealed a positive linear correlation between TEP, RSA-DPPH and FRAP (r2 = 0.85 − 0.98); however, the β-carotene/linoleic acid system (r2 = 0.01 − 0.26) shows low correlation with the TEP levels and other assessment systems. The results suggest that co-products generated from the juice processing of the studied fruit have promising use as a natural source of antioxidants.

Assessment of the antioxidant effect of ethanol extract of Allium sativum L., isolated and/or synergistically associated with synthetic antioxidants, applied to linseed oil

The aim of this study was to assess the antioxidant power of ethanol extract of garlic (EEGL), isolated or associated with synthetic tert-butylhydroquinone (TBHQ) and butylated hydroxytoluene (BHT) antioxidants on the thermal and oxidative stability of linseed oil. The total phenolic content (Folin–Ciocalteu) of EEGL was preliminary determined as a procedure prior to additive supplementation of linseed oil. The EEGL effect, associated or not with TBHQ or BHT, on the oxidative stability of linseed oil was evaluated using the thermogravimetry, pressurized differential scanning calorimetry (PDSC), PetroOxy, and Rancimat. The results showed that EEGL, isolated or associated to synthetic antioxidants, conferred significant increase to the oxidative stability of linseed oil, offering resistance against primary oxidation, especially for samples LOGL 150, LOGL 100, and LOGL/TBHQ (50/50). Given the antioxidant potential and synergistic effect of garlic extract, when used in isolation or associated with TBHQ or BHT, it is feasible to use EEGL for the partial or total replacement of synthetic antioxidants by the edible oils industry.