Percorrer por autor "RODRIGUES, BEATRIZ MARIA LOPES"
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- Extratos de alga como antioxidantes naturais: Mitigação da oxidação lipídica em óleos edíveis e conservas de peixePublication . RODRIGUES, BEATRIZ MARIA LOPES; Domingues, Valentina Maria FernandesThe canning of fish is a process that is used to extend the product's shelf life. However, lipid oxidation can occur and is one of the primary factors affecting shelf life, as it contributes to the formation of rancid flavors, which degrade the sensory qualities of canned fish. In this work the possibility of using seaweed extracts as a natural antioxidant in edible oils is studied. This work aimed to evaluate the use of Palmaria palmata and Porphyra dioica extracts as natural antioxidants in sunflower oil and canned Atlantic mackerel. The study was structured in two main stages: (i) chemical characterization of the extracts (phenolics, reducing capacity, total carotenoids, amino acids profile, metals and iodine), and (ii) application in model systems and real food matrix. A design of experiments was applied to optimize extract conditions in sunflower oil. Samples containing different extract proportions and amounts were subjected to accelerated aging (70°C, 16 days). The oxidative stability of the oils was evaluated by monitoring oxidation markers, such as peroxide value and secondary oxidation compounds. The optimized formulation corresponded to 25 mg of extract per 5 mL of oil at 100% P. dioica. Experimental validation confirmed that results were within the predicted intervals, supporting the robustness of the model. The effect of different parameters in lipid oxidation was analyzed. The results showed that the value of peroxides, carotenoids, phenolics, minerals and amino acids affect negatively the reduction of lipid oxidation. Extracts were then applied to canned Atlantic mackerel prepared using optimal conditions under four conditions (oil/water × with/without extract) and stored for 45 days. Results showed that extracts provided antioxidant protection, though excessive concentrations promoted prooxidant effects. Additionally, a broth was developed from fish residues to valorize by-products. After cooking, filtration, and freeze-drying, the broth will be analyzed for diverse parameters to study its potential use as a low-salt, nutrient-rich seasoning. In conclusion, macroalgae extracts represent a promising natural alternative to synthetic antioxidants in fish canning. Their effectiveness and nutritional value align with consumer demand for cleaner and more sustainable products, though further research is required to confirm long-term stability, sensory impacts, and consumer acceptance.