Influence of home cooking conditions on Maillard reaction products in beef.

The influence of home cooking methods on the generation of Maillard reaction products (MRP) in beef was investigated. Grilling and frying hamburgers to an internal temperature below 90 °C mainly generated furosine. When the temperature reached 90 °C and 100 °C, furosine content decreased by 36% and fluorescent compounds increased by up to 98%. Baking meat at 300 °C, the most severe heat treatment studied, resulted in the formation of carboxymethyllysine. Boiling in water caused very low MRP formation. Acrylamide concentrations in grilled, fried or baked meat were extremely low. Home cooking conditions leading to low MRP generation and pleasant colours were obtained and could be used to guide diabetic and chronic renal patients on how to reduce their carboxymethyllysine intake.

Fish oil and vitamin E change lipid profiles and anti-LDL-antibodies in two different ethnic groups of women transitioning through menopause / El aceite de pescado y la vitamina E modifican el perfil lipídico y los anticuerpos anti-ldl en dos grupos étnicos diferentes de mujeres en transición hacia la menopausia

Background: studies have investigated the relationship between the transition through menopause and cardiovascular diseases. White population, generally, have lower levels of traditional coronary heart risk factors, particularly dyslipidemia, hypertension, obesity, and diabetes, and lower rates of coronary heart disease mortality, than black population. Furthermore many studies have shown the cardioprotective and anti-inflammatory effects of omega-3 polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid) of marine origin. The aim of this study was to investigate the effect of omega-3 supplementation, combined or not with vitamin E, on oxidative biomarkers and lipid profiles in nonwhite and white women with dyslipidemia transitioning through menopause. Methods: a randomized, double-blind, placebo-controlled trial was conducted. Seventy-four eligible women were assigned to receive: fish oil, fish oil plus vitamin E and placebo for three months. At baseline, 45 and 90 days blood sample for biochemical variables and biomarkers of oxidative stress were taken. Socioeconomic and lifestyle variables were collected with standardized questionnaires. Results: after 90 days the fish oil plus vitamin E treated group had a significant decrease in total cholesterol and LDL-C. Furthermore, there was a decrease in anti-LDL- autoantibodies after 45 days. Plasma TBARS concentrations were increased after 90 days in the group receiving only fish oil when compared to the placebo and fish oil-vitamin E groups. All of the effects observed were independent of ethnic group. Conclusion: supplementation with fish oil and vitamin E reduced total cholesterol and LDL-C, but had opposite. effects on oxidative stress compared to supplementation with fish oil alone (AU)

Introducción: diversos estudios han investigado la relación entre la transición a la menopausia y las enfermedades cardiovasculares. Generalmente, la población de etnia blanca posee bajos niveles de factores de riesgo coronarios, particularmente dislipidemia, hipertensión, obesidad, diabetes y bajas tasas de mortalidad por enfermedades del corazón en comparación con la población de etnia negra. Además, varios estudios demostraron efectos cardioprotectores y antiinflamatorios provenientes de ácidos grasos poliinsaturados omega-3 (ácido eicosapentaenoico y ácido docosahexaenoico) de origen marino. El objetivo del estudio fue investigar el efecto de la suplementación de omega-3 combinado o no con vitamina E en biomarcadores oxidativos y perfiles lipídicos en mujeres blancas y no blancas con dislipidemia en transición hacia la menopausia. Métodos: fue realizado un estudio randomizado, duplo-ciego, placebo-controlado. Setenta y cuatro mujeres elegibles fueron escogidas para recibir: aceite de pescado, aceite de pescado con vitamina E y placebo durante tres meses. Fueron recogidas muestras de sangre en de referencia, 45 y 90 días para realizar exámenes bioquímicos y de biomarcadores para estrés oxidativo. Las variables socioeconómicas y de estilo de vida fueron recogidas por medio de cuestionarios estandarizados. Resultados: después de 90 días, el grupo tratado con aceite de pescado con vitamina E tuvo una disminución significativa para colesterol total y LDL-C. Además, hubo una disminución de anticuerpos anti-LDL después de 45 días. La concentración de plasma TBARS aumentó después de 90 días en el grupo que recibió solamente aceite de pescado, comparado con los grupos placebo y aceite de pescado con vitamina E. Todos los efectos observados fueron independientes del grupo étnico. Conclusión: la suplementación con aceite de pescado y vitamina E redujo el colesterol total y LDL-C, pero tuvo un efecto opuesto en el estrés oxidativo comparado con la suplementación solamente con aceite de pescado (AU)

Major peptides from amaranth (Amaranthus cruentus) protein inhibit HMG-CoA reductase activity.

The objective of this study was to identify the major peptides generated by the in vitro hydrolysis of Amaranthus cruentus protein and to verify the effect of these peptides on the activity of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase), a key enzyme in cholesterol biosynthesis. A protein isolate was prepared, and an enzymatic hydrolysis that simulated the in vivo digestion of the protein was performed. After hydrolysis, the peptide mixture was filtered through a 3 kDa membrane. The peptide profile of this mixture was determined by reversed phase high performance chromatography (RP-HPLC), and the peptide identification was performed by LC-ESI MS/MS. Three major peptides under 3 kDa were detected, corresponding to more than 90% of the peptides of similar size produced by enzymatic hydrolysis. The sequences identified were GGV, IVG or LVG and VGVI or VGVL. These peptides had not yet been described for amaranth protein nor are they present in known sequences of amaranth grain protein, except LVG, which can be found in amaranth α­amylase. Their ability to inhibit the activity of HMG-CoA reductase was determined, and we found that the sequences GGV, IVG, and VGVL, significantly inhibited this enzyme, suggesting a possible hypocholesterolemic effect.

Amaranth oil increased fecal excretion of bile Acid but had no effect in reducing plasma cholesterol in hamsters.

Hamsters were fed for 4 weeks on four different diets: control (C) (balanced diet containing 20 % corn oil as the lipid source), hypercholesterolemic (H) (identical to C but containing 12 % coconut oil, 8 % corn oil and 0.1 % cholesterol as the lipid source), amaranth oil (A) (identical to H without corn oil but with amaranth oil), and squalene (S) (identical to H but admixed with squalene in the ratio found in amaranth oil). There were no significant differences in lipid profile, and in the cholesterol excreted in the animals' feces from amaranth oil (A) and squalene (S) groups. Fecal excretion of bile acids was greater in the amaranth oil (A) and squalene groups (S) as compared to the other groups. The scores of steatosis and parenchymal inflammation observed in the amaranth oil (A) and squalene groups (S) were superior to the ones observed in the other groups. Our findings demonstrated that amaranth oil, and its component squalene, increased the excretion of bile acids but did not have a hypocholesterolemic effect in hamsters fed on a diet containing high amounts of saturated fat and cholesterol.

Efeito do processamento na atividade antioxidante do grão de amaranto (Amaranthus cruentus L. BRS-Alegria) / Effect of processing on the antioxidant activity of amaranth grain

As características nutricionais, funcionais e agrícolas do amaranto são responsáveis pelo aumento do interesse por este alimento nas últimas décadas. O grão pode ser cozido, estourado, torrado, extrusado ou moído para ser consumido. Foi avaliado o efeito destes processamentos na atividade antioxidante do grão de amaranto, através das determinações do teor de fenólicos totais e da atividade antioxidante in vitro por dois métodos: inibição da oxidação lipídica pelo sistema β-caroteno/ácido linoléico e índice de atividade antioxidante pelo aparelho Rancimat®. Os processamentos reduziram em média o teor de fenólicos totais do grão de amaranto de 31,7 para 22,0 mg de equivalentes de ácido gálico/g de resíduo seco. Observou-se que o extrato obtido por etanol do grão torrado foi o único a apresentar menor índice de atividade antioxidante (IAA) em relação ao grão cru (1,3 v 1,7). Os processos de extrusão, torração e explosão não alteraram a capacidade de inibição da oxidação lipídica (IOL) do amaranto (55 por cento). Já o cozimento aumentou o IOL (79 por cento), o que pode ter ocorrido devido ao maior tempo de processamento sob alta temperatura (100ºC/10min). Os métodos mais comuns de processamento do grão de amaranto ocasionaram redução do teor de fenólicos totais, no entanto a atividade antioxidante do estourado e do extrusado, avaliada pelos dois métodos, foi semelhante ao do grão cru. O grão de amaranto tanto cru como processado apresenta potencial antioxidante. Polifenóis, antocianinas, flavonóides, tocoferóis, vitamina C e compostos gerados na reação de Maillard podem estar relacionados à atividade antioxidante deste grão.

Amaranth has attracted increasing interest over recent decades because of its nutritional, functional and agricultural characteristics. Amaranth grain can be cooked, popped, toasted, extruded or milled for consumption. This study investigated the effect of these processes on the antioxidant activity of amaranth grain. Total phenolic content and in vitro antioxidant activity were determined according to two methods: inhibition of lipid oxidation using the β-carotene/linoleic acid system and the antioxidant activity index using the Rancimat® apparatus. The processing reduced the mean total phenolics content in amaranth grain from 31.7 to 22.0 mg of gallic acid equivalent/g of dry residue. It was observed that the ethanol extract from toasted grain was the only one that presented a lower antioxidant activity index compared with the raw grain (1.3 versus 1.7). The extrusion, toasting and popping processes did not change the capacity to inhibit amaranth lipid oxidation (55 percent). However, cooking increased the inhibition of lipid oxidation (79 percent), perhaps because of the longer time at high temperatures in this process (100°C/10 min). The most common methods for processing amaranth grain caused reductions in the total phenolics content, although the antioxidant activity of popped and extruded grain, evaluated by the two methods, was similar to that of the raw grain. Both raw and processed amaranth grain presents antioxidant potential. Polyphenols, anthocyanins, flavonoids, tocopherols, vitamin C levels and Maillard reaction products may be related to the antioxidant activity of this grain.

Efeito do beneficiamento sobre o valor nutricional do peixe mandim Arius spixii / Effect of processing on nutritional value of the mandim fish Arius spixii

Com o objetivo de avaliar o efeito do beneficiamento sobre o valor nutricional do peixe mandim (Arius spixii) comercializado em Maceió-AL, determinaram-se nas suas formas in natura e beneficiada (salgado-seco) a composição centesimal, valor calórico,cloretos, perfil de ácidos graxos e colesterol, sendo também analisada a ocorrência de óxidos de colesterol. Os resultados obtidos para o mandim in natura e beneficiado, respectivamente, de umidade (70,13% e 40,31%), proteínas (51,73% e 38,07%, base seca), carboidratos (4,67% e 2,24%, base seca), calorias (486 kcal/100ge 367 kcal/100g, base seca), ácidos graxos (poliinsaturados 14,54% e 15,49%, ômega-3 8,51% e 6,51%), colesterol (82,66 mg/100g e 61,30 mg/100g) e óxidos (7-cetocolesterol 8,31 μg/g e 17,90 μg/g), permitiram concluir que o beneficiamento favoreceu alterações significativas no valor nutricional do mandim.

In an attempt to analyze how processing enhances the nutritional value of the mandim fish (Arius spixii) marketedin Maceió-AL, Brazil, the following nutritional components were determined in fresh and processed (salted-dried) fish: centesimal composition, calorie count, chloride, fatty acid and cholesterol profile. The presence of cholesterol oxides was also investigated. Respective results for fresh and processed mandim fish were: moisture (70.13% and 40.31%), proteins (51.73% and 38.07%, dried),carbohyrdrates (4.67% and 2.24%, dried), calories (486 kcal/100g and 367 kcal/100g, dried), fatty acids(polyunsaturared 14,54% and 15,49%, ômega-3 8,51% and 6,51%), cholesterol (82.66 mg/100g and 61.30 mg/100g) and oxides (7-ketocholesterol 8.31 μg/g and 17.90 μg/g). These figures clearly showed that processing led to significant change in the nutritional value of the mandim fish.

Identificação de peptídeos hipocolesterolemizantes do isolado protéico do grão de amaranto (Amaranthus cruentus L. BRS-Alegria) / Identification of peptides hipocolesterolemizantes of protein isolate of the grain amaranth (Amaranthus cruentus L. BRS-Alegria)

Introdução: Dentre os distúrbios relacionados à alimentação, o aumento do colesterol e, conseqüentemente, a incidência de doenças cardiovasculares, representa um importante problema de Saúde Pública. A proteína do amaranto reduz o colesterol plasmático, possivelmente pela presença de peptídeos bioativos, liberados durante sua digestão parcial. Objetivo: Verificar a ocorrência de peptídeos hipocolesterolemizantes após digestão in vitro do isolado protéico de amaranto. Métodos: Proteína isolada do amaranto foi submetida à digestão enzimática in vitro por duas metodologias distintas. Os peptídeos menores que 3000 Da foram injetados em espectrômetro de massa para sua identificação. Resultados: Foi obtido isolado protéico com grau de pureza acima de 90. O isolado protéico e a farinha integral apresentaram a mesma quantidade de aminoácidos essenciais e de aminoácidos presentes nas seqüências dos peptídeos de interesse. O isolamento protéico também não promoveu alterações nas principais frações moleculares. As estruturas terciária e quaternária provavelmente foram alteradas, pois houve redução da solubilidade protéica. O grupo dissulfeto é um dos responsáveis pela ocorrência de agregados, entretanto outras ligações também podem estar envolvidas. Essas forças podem interferir no acesso aos sítios de clivagem das ligações peptídicas e dificultar a ação enzimática. Devido ao aumento da força iônica do meio obteve-se alto grau de hidrólise em ambos os métodos enzimáticos. A digestão protéica resultou em fragmentos que, em sua maioria, apresentaram pesos moleculares inferiores a 30 kDa.O perfil peptídico, para a maior parte das amostras, mostrou-se complexo, com difícil separação de picos. A amostra hidrolisada que apresentou menor grau de hidrólise e menor quantidade de picos no cronograma continha um dos peptídeos hipocolesterolemizantes procurados, o fragmento IAEK. Conclusões: O solado protéico de amaranto apresenta pelo menos um peptídeo hipocolesterolemizante qua...