RESUMO
In the present investigation we ascertained the stability of lycopene, ß-carotene, ascorbic acid, polyphenolic compounds and total antioxidant capacity (AC) during the process of concentrating tomatoes into two tomato pastes (10 and 15ºBrix). Thermal processing increased the content of lycopene, total phenolic compounds, total flavonoids, and the individual phenolic compounds quercetin, rutin, chlorogenic and cafeic acids, whereas it decreased the other analysed compounds. However, lycopene in the 15ºBrix-tomato paste decreased due to the extension of thermal processing, which led to degradation. The AC of aqueous and organic extracts was measured and different AC values were observed depending on the antioxidant profile of the extract and assay used (TEAC and FRAP). AC expressed in dry matter decreased as result of ascorbic acid losses. Overall, thermal processing enhanced the nutritional value of tomatoes, mainly by increasing the lycopene and phenolic antioxidants, but the extension of treatment must be controlled to prevent lycopene degradation.
En el presente trabajo hemos estudiado la estabilidad del licopeno, ß-caroteno, ácido ascórbico, compuestos fenólicos y capacidad antioxidante total (AC) durante el procesado de concentración del tomate en dos pastas de tomate (10 y 15ºBrix). El tratamiento térmico incrementó el contenido de licopeno, compuestos fenólicos totales, flavonoides totales y el contenido de quercetina, rutina y ácido clorogénico y cafeíco, disminuyendo el contenido de los otros compuestos analizados. Sin embargo, el contenido de licopeno en la pasta de tomate de 15ºBrix disminuyó debido al tratamiento térmico como consecuencia de la degradación térmica. La AC de los extractos acuosos y orgánicos de las muestras proporcionaron diferentes resultados dependiendo del perfil de antioxidante extraído y del método de análisis utilizado (TEAC y FRAP). La AC expresada en material seca disminuyó como resultado de las pérdidas de ácido ascórbico. En general el procesado térmico incrementa el valor nutricional del tomate , debido principalmente al incrmento de licopeno y compuestos fenólicos, pero la extensión del tratamiento en tiempo y temperatura debe ser controlado para prevenir la degradación del licopeno.
Assuntos
Antioxidantes/análise , Ácido Ascórbico/análise , Carotenoides/análise , Manipulação de Alimentos/métodos , Temperatura Alta , Solanum lycopersicum/química , Fenóis/análise , Solanum lycopersicum/metabolismo , Valor Nutritivo , Fatores de TempoRESUMO
In the present investigation we ascertained the stability of lycopene, beta-carotene, ascorbic acid, polyphenolic compounds and total antioxidant capacity (AC) during the process of concentrating tomatoes into two tomato pastes (10 and 15 degrees Brix). Thermal processing increased the content of lycopene, total phenolic compounds, total flavonoids, and the individual phenolic compounds quercetin, rutin, chlorogenic and cafeic acids, whereas it decreased the other analysed compounds. However, lycopene in the 15 degrees Brix-tomato paste decreased due to the extension of thermal processing, which led to degradation. The AC of aqueous and organic extracts was measured and different AC values were observed depending on the antioxidant profile of the extract and assay used (TEAC and FRAP). AC expressed in dry matter decreased as result of ascorbic acid losses. Overall, thermal processing enhanced the nutritional value of tomatoes, mainly by increasing the lycopene and phenolic antioxidants, but the extension of treatment must be controlled to prevent lycopene degradation.
Assuntos
Antioxidantes/análise , Ácido Ascórbico/análise , Carotenoides/análise , Manipulação de Alimentos/métodos , Temperatura Alta , Fenóis/análise , Solanum lycopersicum/química , Solanum lycopersicum/metabolismo , Valor Nutritivo , Fatores de TempoRESUMO
Phenols are one of the major groups of nonessential dietary components appearing in vegetable foods. They are a wide chemical compounds group that are considered as secondary plant metabolites, with different activity and chemical structure, including more than 8,000 different compounds. Phenols, has traditionally been considered as antinutritive compounds due to the adverse effect of one of their main components, tannins, on protein digestibility. However, actually there is an increased interest in these compounds because they have been associated with the inhibition of atherosclerosis and cancer. The bioactivity of phenolics may be related to their antioxidant behaviour, which is attributed to their ability to chelate metals, inhibit lipoxygenase and scavenge free radicals. This review make a global view on the main phenolic compound groups, their organoleptic effects in vegetable foods, their physiological effects in humans, their metabolism, bioavailability as well as their content in the diet.
Assuntos
Antioxidantes , Dieta , Flavonoides , Frutas/química , Fenóis , Polímeros , Verduras/química , Animais , Antioxidantes/química , Antioxidantes/metabolismo , Humanos , Valor Nutritivo , Fenóis/química , Fenóis/metabolismo , Polímeros/química , Polímeros/metabolismo , PolifenóisRESUMO
The nutritional need for iron in living organisms is derived from the central role that it plays in the energy metabolism of living cells. However, iron exists in almost exclusively in the less soluble oxidised state (Fe III). This has greatly reduce its accessibility. Iron in foods exist in two main forms: haem iron and non-haem iron, which are absorbed by different pathways with different degrees of efficiency depending upon dietary and physiological factors. All these factors increase or reduce the proportion of the total iron in a food or diet that is utilised for metabolism, that is iron bioavailability. Iron deficiency leads to anaemia, one of the most common nutritional deficiency disorders in the world both in industrialised and developing countries. Preventing this illness is based on a gradual growth in our understanding of iron nutrition.
Assuntos
Alimentos , Ferro/farmacocinética , Absorção , Disponibilidade Biológica , Humanos , Necessidades Nutricionais , VerdurasRESUMO
Blanched (95 degrees C, 5 min), autoclaved (100 degrees C, 5 min) artichoke hearts and their by-product (external leaves and distal portion of stem) were analysed for amino acid composition, "in-vitro" protein digestibility (DIVP), and dietary fiber. Amino acid score of the three samples was in a good agreement with FAO/WHO recommendations including sulphur amino acids. Dietary fiber content was high in all samples, decreasing in autoclaved artichokes that might be relate with the improvement of DIVP. By-product was consider a potential food source because it showed a good amino acid profile and the highest levels of DIVP (76.4%), but fibrouness was also too high (51.6%).
Assuntos
Aminoácidos/análise , Manipulação de Alimentos , Temperatura Alta , Verduras/química , Fibras na Dieta/análise , Valor NutritivoRESUMO
Selenium is an important trace element that was considered toxic for humans and animals for a long time. The best known biochemical role of selenium is, as a selenocysteine residue, to be a part of the active site of the enzyme glutathione peroxidase (GSH-Px). The highest values of selenium have been found in protein foods (meat and fish); although selenium from vegetables sources are more available than from the other foods. Nowadays are not known exactly the recommended dietary allowances for humans, mainly for children. The selenium intake in Spain is 221 micrograms/person/day and the plasmatic values of Spanish people (87 +/- 14 micrograms/L) are within the European average (85 micrograms/L).
Assuntos
Selênio/análise , Animais , Grão Comestível/química , Humanos , Carne/análise , Proteínas do Leite/análise , Ratos , Verduras/químicaRESUMO
Physiological effects of dietary fiber (DF) are the result of complex interacting mechanisms between the components of food which is not digested by the endogenous enzymes of the digestive tract and the conditions of gastrointestinal environment, such as pH, ionic strength and other food components. Chemical nature and structure of each component of DF are two factor that determine their behaviour in lumen intestinal. This article report the main functional properties of DF and explain how these are responsible of physiological effects developed by DF in gastrointestinal tract.