ANTIOXIDANT ACTIVITY OF PLANT EXTRACTS AND BREADS ENRICHED WITH THESE EXTRACTS

The enrichment of foods with bioactive compounds has been widely studied due to the numerous potentials attributed to these compounds. Among these potentials, the antioxidant and antimicrobial activity stands out. Many plant species have high concentrations of bioactive compounds, especially phenolic compounds, which are also linked to health benefits, such as the prevention of cancer and cardiovascular diseases. In this scenario, the present work evaluated the antioxidant potential of plant extracts obtained using green and GRAS solvents and the phenolic concentration and antioxidant activity of traditional bread enriched with these extracts. The plants selected were garlic (Allium sativum); thyme (Thymus vulgaris), and coffee (Coffea sp.), and the extracts were obtained by sequential extraction using water and ethanol solvents, processed until obtaining concentrated aqueous extracts. The extracts were submitted for analysis to evaluate the antioxidant activity using Folin-Ciocalteau, FRAP, and ABTS colorimetric methods. After obtaining the extracts, traditional bread was produced and enriched with different extract concentrations. The concentrations tested were defined in previous studies (unpublished), being selected the following: garlic (1.5%; 3%; 4.6% / flour base), thyme (1.5%; 3%; 6% / flour base) and coffee (1.73%; 3.7%; 6% / flour base), added to the dough and applied on the surface of breads after baking. The extracts showed similar antioxidant activity to the described in the literature, with emphasis on coffee, with a higher concentration of phenolics (10,503.86 mg EAG/L ± 319.02) and higher antioxidant activity in both methods. Another highlight was the garlic extract, presenting a phenolic concentration 22 times lower than coffee extract and the lowest antioxidant activity. The bread enriched with garlic and coffee showed an increasing phenolic content according to the concentration of added extract, different from the bread enriched with thyme extract: the highest concentration (6%) had the lower concentration of phenolics. On the other hand, antioxidant activity by the FRAP method did not show a pattern in the variation within the concentrations test. The concentrations with the highest activity were 6% (234.00µM de Trolox ± 4.9, for bread enriched with garlic), 3% (235.88µM de Trolox ± 8.87, for bread enriched with thyme), and 6% (1,187.52µM de Trolox ± 4.75, for bread enriched with coffee). ABTS method revealed a higher antioxidant activity (94.97µM de Trolox ± 1.69) for the lowest concentration of garlic (1.5%) compared to bread with greater addition of this extract. The particularities observed may be related to the individual characteristics of the compounds present in the extracts and their interaction with the food matrix. Furthermore, the baking process can cause changes in phenolic concentrations to a greater or lesser extent, depending on the chemical species in question. In short, the results indicate that, for the matrix evaluated, the enrichment with plant extracts may not result in the final concentration and availability of compounds initially predicted. The interactions of bioactive compounds, especially phenolics, must be evaluated in each matrix to define the ideal amounts of incorporation of these compounds for better use and effect.