Helena Maria Pinheiro-Sant'Ana

Optimization of methodology to analyze ascorbic and dehydroascorbic acid in vegetables

In this study, different solutions to extract vitamin C were tested. High-performance liquid chromatography was chosen and the conditions were based on isocratic elution in reverse phase column. Dehydroascorbic acid was determined indirectly after its reduction using dithiothreitol. The use of metaphosphoric acid to stabilize the vitamin C was shown to be required and it was necessary to neutralize the pH of the extract to apply dithiothreitol. The average recovery was 90% in collard and tomato samples. The presence of oil did not interfere in extraction and the methodology can be used to analyze stir fried vegetables.

Sorghum (Sorghum bicolor L.): Nutrients, bioactive compounds, and potential impact on human health.

ABSTRACT Sorghum is the fifth most produced cereal in the world and is a source of nutrients and bioactive compounds for the human diet. We summarize the recent findings concerning the nutrients and bioactive compounds of sorghum and its potential impact on human health, analyzing the limitations and positive points of the studies and proposing directions for future research. Sorghum is basically composed of starch, which is more slowly digested than that of other cereals, has low digestibility proteins and unsaturated lipids, and is a source of some minerals and vitamins. Furthermore, most sorghum varieties are rich in phenolic compounds, especially 3-deoxyanthocyanidins and tannins. The results obtained in vitro and in animals have shown that phenolics compounds and fat soluble compounds (polycosanols) isolated from sorghum benefit the gut microbiota and parameters related to obesity, oxidative stress, inflammation, diabetes, dyslipidemia, cancer, and hypertension. The effects of whole sorghum and its fractions on human health need to be evaluated. In conclusion, sorghum is a source of nutrients and bioactive compounds, especially 3-deoxyanthocyanidins, tannins, and polycosanols, which beneficially modulate, in vitro and in animals, parameters related to noncommunicable diseases. Studies should be conducted to evaluate the effects of different processing on protein and starch digestibility of sorghum as well as on the profile and bioavailability of its bioactive compounds, especially 3-deoxyanthocyanidins and tannins. Furthermore, the benefits resulting from the interaction of bioactive compounds in sorghum and human microbiota should be studied.

A deficiência de vitamina A em crianças no Brasil e no mundo

Based on a ten-year literature review, this paper describes important aspects of Vitamin A Deficiency (VAD) among children in Brazil and worldwide. It presents VAD within a clinical and sub-clinical deficiency context, emphasizing this as a public health issue. VAD has been diagnosed in children from several parts of Brazil, especially in the Southeast and Northeast. Worldwide, the highest VAD prevalence is found in parts of parts of Africa: Mali, Ethiopia and Nigeria, and clinical indications noted especially in parts of Asia and Africa. However, no studies of clinical indications were located. Studies point to VAD as a public health issue among children, particularly in the poorest parts of the world.

Adição da vitamina E aos alimentos: implicações para os alimentos e para a saúde humana

Taking vitamin E in higher doses than those recommended by the Dietary Reference Intake in foods or supplements helps prevent non-communicable chronic diseases, stimulates the immune system and modulates the degenerative processes associated with aging. On the other hand, the addition of vitamin E to foods to obtain those effects is not common yet because there is no consensus on an ideal dose. Vitamin E has been added to the foods consumed by some populations because their intake used to be below the recommended amount. This study focuses on the role of vitamin E (1) as an antioxidant used by the food industry, (2) as acompound with specific functions in the human body and in foods, (3) as an important nutrient that, when added to foods, is capable of inhibiting lipoperoxidation and increase its intake and (4) as a substance that might be capable of reducing the deleterious effects of the oxidative processes that occur in the human body and therefore helping to prevent non-communicable chronic diseases.

Tocoferois e tocotrienois em óleos vegetais e ovos

The distribution and content of vitamin E isomers was investigated in vegetable oils and raw and cooked egg yolk in commercial restaurants. The analysis of the eight vitamin E isomers was carried out by High Performance Liquid Chromatography (HPLC) with fluorescence detection. The tocopherol and tocotrienol composition of foods varied considerably. Tocopherols were detected in greater quantity and frequency. The α-tocopherol predominated in egg yolks and olive oil while γ-tocopherol was found in high quantities in soybean and canola oils. Cooking did not cause major losses for most of the vitamin E isomers in egg yolks.

Biodisponibilidade de vitaminas lipossolúveis

O termo biodisponibilidade representa a parte do nutriente ingerido que tem o potencial de suprir as demandasfisiologicas em tecidos alvos; por definicao, nao corresponde, na maioria das vezes, a quantidade ingerida.Apesar da concordância entre alguns pesquisadores no que se refere ao conceito de biodisponibilidade,varios termos sao comumente utilizados em trabalhos cientificos como sinonimos desse, em funcao daspeculiaridades dos metodos empregados na sua determinacao. Estudos de balanco, relacao dose-efeito e usode isotopos sao alguns dos metodos mais comumente utilizados para determinar a biodisponibilidade devitaminas. Tais metodologias, alem de avaliar a biodisponibilidade do nutriente, devem tanto quanto possivelprocurar elucidar ou levar em consideracao os fatores que interferem na sua absorcao e utilizacao. Dentreesses fatores, estao a interacao com outros nutrientes ou componentes da dieta e as condicoes fisiologicasdos organismos submetidos ao estudo. As vitaminas lipossoluveis, devido ao seu metabolismo complexo,diversidade funcional e mecanismo de absorcao relacionado a lipoproteinas, apresentam alguns problemasespecificos no que se refere a avaliacao de sua biodisponibilidade em alimentos ou dietas, necessitando, porocasiao dos ensaios, de um criterioso planejamento e analise de resultados. Dessa forma, ressaltaram-se,nesta revisao, alguns aspectos importantes com relacao a biodisponibilidade das vitaminas lipossoluveis,como: diversidade de termos usados, metodologia para avaliacao, fatores que interferem na absorcao eutilizacao, entre outros, visto que a avaliacao da biodisponibilidade de algumas vitaminas lipossoluveis aindanao possui metodos validados, gerando uma grande variacao nos resultados obtidos nas pesquisas realizadasnesta area.

Otimização de método para análise de folatos em hortaliças folhosas por cromatografia líquida de alta eficiência com detecção por fluorescência

We optimized a method for the determination of three main folate isoforms in leafy vegetables. Analysis was carried out by HPLC, using gradient of elution and fluorescence detection. Limits of quantification were 2 ng/mL; 2 ng/mL and 28 ng/mL for tetrahydrofolate (THF), 5-methyltetrahydrofolate (5-MTHF) and 5-formyltetrahydrofolate (5-FTHF), respectively. Recovery rates of THF, 5-MTHF and 5-FTHF varied from 87.86 to 100.64%; 88.12-94.22% and 89.82-106.69%, respectively. Test of repeatability showed relative standard deviation for peak areas lower than 10%. Tests for linearity showed high coefficients of determination. The results showed advances in folates extraction and analysis in raw and cooked leafy vegetables.

Pró-vitaminas A em hortaliças comercializadas no mercado formal e informal de Viçosa (MG), em três estações do ano

With the aim of providing data on the influence of climate and form of commercialization on carotenoid of vegetables, this study evaluate the content of a and b carotene and vitamin A value of seven vegetables (sweet potato, carrot, squash, green pepper, okra, tomato and green bean) market in Vicosa (MG), Brazil, using High Performance Liquid Chromatography (HPLC). It was compared vegetables commercialized in two local markets and in the free market during spring, summer and autumn. Carrot presented the highest values of a and b-carotene (31.17 e 58.18 µg/g, respectively), followed by squash (4.33 and 23.16 µg/g, respectively), while sweet potato presented the lowest value of b carotene (0.51 µg/g). The vitamin A values varied as the profile of a and b-carotene content. The results showed that, except for carrot and okra, there was no significant influence of the market type on the content of carotenoids. The variation of the content of a and b-carotene in the seasons was not important, and only green pepper presented significantly different values. Portions of 100 g of analyzed vegetables supply 3 to 78% of vitamin A recommendation.

Evaluation of total carotenoids, alpha- and beta-carotene in carrots (Daucus carota L.) during home processing

This study aims to analyze the influence of dehydration and different preparation methods during home processing related toa-carotene, b-carotene and total carotenoids stability in carrots. Vitamin A values were evaluated after different treatments. Thus, carrots were submitted to steam cooking, water cooking with and without pressure, moist/dry cooking and conventional dehydration. Determination of a- and b-carotenes was made by High-Performance Liquid Chromatography (HPLC) (conditions were developed by us) using spectrophotometric detection visible-UV at 470 nm; a RP-18 column and methanol: acetonitrile: ethyl acetate (80: 10: 10) as mobile phase. Total carotenoids quantification was made by 449 nm spectrophotometer. The retention of the analyzed carotenoids ranged from 60.13 to 85.64%. Water cooking without pressure promoted higher retention levels of a- and b-carotene and vitamin A values, while water cooking with pressure promoted higher retention levels of total carotenoids. Dehydration promoted the highest carotenoid losses. The results showed that, among the routinely utilized methods under domestic condition, cooking without pressure, if performed under controlled time and temperature, is the best method as it reduces losses in the amount of a- and b-carotene, the main carotenoids present in the carrots. Despite the significant carotenoid losses, carrots prepared through domestic methods, remain a rich source of provitamin A.

Fortification of industrialized foods with vitamins

Vitaminas sao nutrientes essenciais a vida. Habitos alimentares inadequados, alto consumo energetico e falhas no metabolismo levam a deficiencias de micronutrientes, que afetam mais de dois bilhoes de pessoas mundialmente. O consumo, cada vez maior, de alimentos industrializados, somado a baixa estabilidade das vitaminas, tem induzido a pratica de adicao de nutrientes aos alimentos processados. Esta revisao discute terminologia, disponibilidade, ingestao e risco de hipervitaminose devida ao consumo desses produtos, e a importância nutricional dos de alimentos fortificados com vitaminas. A adicao de nutrientes deve ocorrer em alimentos que, efetivamente, participem da dieta da populacao alvo e deve obedecer as necessidades reais de segmentos significativos da populacao. No Brasil, se encontra, disponivel em supermercados, um total de 166 produtos enriquecidos com vitaminas. Um estudo de coorte de 10 anos, desenvolvido na Alemanha, com criancas e adolescentes, comprovou que 90% dos pesquisados utilizaram, pelo menos, um alimento fortificado. Ao longo do periodo estudado, observou-se o consumo de 472 diferentes produtos fortificados. O enriquecimento de alimentos, entretanto, deveria basear-se nas necessidade de cada pais, e, se possivel, nas necessidades regionais, que variam de regiao a regiao. Na Dinamarca, por exemplo, durante o inverno, e principalmente nos idosos, a vitamina D necessita ser adicionada aos alimentos, para que aumente o seu consumo. No Brasil, diferentemente, nao ha evidencias de necessidade de fortificacao de alimentos com essa vitamina. Apesar disso, uma investigacao mostrou que, de 76 produtos lacteos enriquecidos, 37 continham vitamina D. A fortificacao de alimentos e uma estrategia importante para resolver problemas de deficiencia nutricional, porem tambem pode ocasionar muitos danos a saude.