Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.18/5320
Título: Is thermal treatment a concern for the nutritional quality of flaxseed, chia and sunflower seeds?
Autor: Albuquerque, T.G.
Silva, M.A.
Oliveira, M.B.P.P.
Costa, H.S.
Palavras-chave: Nutritional Quality
Sunflower Seeds
Segurança Alimentar
Data: Dez-2017
Editora: Instituto Nacional de Saúde Doutor Ricardo Jorge, IP
Resumo: Oilseeds production has increased due to several food industry applications to answer consumers demand for foods with potential health benefits. Most of these benefits are related to the fatty acids profile, since oilseeds are particularly rich in polyunsaturated fatty acids that decrease the risk of several chronic diseases. From the food industry perspective, their application in the enrichment of breads, cakes, cookies and cereal bars, is a challenge. All these products are submitted to different processing methods, including heat treatment, being therefore essential to evaluate their impact on the nutritional value, namely in the fatty acid profile and oxidative stability of oilseeds. In 2016, samples of flaxseeds (Linum usitatissimum L.), chia (Salvia hispanica) and sunflower (Helianthus annuus L.) seeds were obtained from supermarkets in the Lisbon region. The samples were subjected to heat treatment (180 °C) for 10, 20, 30 and 60 minutes. Oilseeds fat was extracted with petroleum ether and for the methylation of the fatty acids a cold transesterification was performed using n-heptane and a methanolic solution of potassium hydroxide (2 M). Chromatographic separation of fatty acid methyl esters was then performed using a gas chromatograph coupled to flame ionization detector. For all the analysed oilseeds, the major fatty acids were polyunsaturated. Nonetheless, for chia and flaxseeds the major polyunsaturated fatty acid was alpha-linolenic (omega 3) fatty acid, while for sunflower seeds the major fatty acid was linoleic acid (omega 6). Foods containing high levels of polyunsaturated fatty acids are more susceptible to lipid oxidation, and some of the conditions that can trigger the oxidation process are the presence of oxygen, exposure to light, and/or heat treatment. In this work, after applying heat treatment on the different types of seeds, it was possible to conclude that no considerable changes were observed in the fatty acid profile of chia, sunflower and flaxseeds. This could be due, in part, to the presence of antioxidant compounds, such as phytosterols and tocopherols, but also due to the temperature of the heat treatment.
Peer review: yes
URI: http://hdl.handle.net/10400.18/5320
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