Browsing by Author "Salgado, N."
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- Analysis of total vitamin C, ascorbic acid and dehydroascorbic acid in red fruits and green leafy vegetables by HPLC-PDAPublication . Salgado, N.; Silva, M.A.; Costa, H.S.; Figueira, M.E.; Albuquerque, T.G.Ascorbic acid (AA), also known as vitamin C, is an essential micronutrient due to its role in human development and wellbeing since it has antioxidant properties and is involved in the production of proteins like collagen. [1] It has been associated with several health benefits: reduced risk of mortality, cardiovascular disease, different types of cancer, and respiratory and neurological issues. [2] Despite being mainly found in citrus species, AA also exists in other fruits and vegetables. This study aimed to assess the variability of vitamin C content in red fruits (strawberry, raspberry and blueberry) and green leafy vegetables (spinach and lettuce) from different brands and supermarkets, measuring total vitamin C, by high-performance liquid chromatography with photodiode array detection (HPLC-PDA), an extremely sensitive and validated method. According to our results, brand B of strawberry was the richest in total vitamin C (51.3 mg/100 g) with 45 mg/100 g of AA and 6.27 mg/100 g of DHA, followed by brand A of raspberry (44.7 mg/100 g), being the majority AA. On the contrary, all brands of blueberry did not contain any form of vitamin C and brand B of lettuce had 5.01 mg/100 g of total vitamin C, reporting the lowest detectable value. Within the different brands, total vitamin C ranged between 37.4-51.3, 20.8-44.7, 5.01-5.13 and 10.1-12.4 mg/100 g for strawberry, raspberry, lettuce and spinach, respectively. Thus, red berries seem to have higher quantity of vitamin C than green leafy vegetables, except for blueberry. Differences between the same food of distinct brands can be justified due to cultivation practices, ripeness, environmental and soil conditions, as well as storage conditions since vitamin C is sensitive to heat, light, and oxygen. Furthermore, consulting Regulation Nº 1169/2011, which indicates 80 mg of vitamin C as daily reference dose for adults, consuming 1 portion (160 g) of brand B of strawberry will make you achieve 103% of the recommendation. References: [1] Santos, K et al. (2022) Essential features for antioxidant capacity of ascorbic acid (vitamin C). J Mol Model., 28, 1-8; [2] Xu, K et al. (2022) Vitamin C intake and multiple health outcomes: an umbrella review of systematic reviews and meta-analyses. Int J Food Sci Nutr., 73, 588-599.
- Consumers' perceptions and consumption behaviour concerning red fruitsPublication . Salgado, N.; Silva, M.A.; Figueira, M.E.; Costa, H.S.; Albuquerque, T.G.Consumers' concern for disease prevention makes them aware of the importance to follow a healthy diet. Red fruits are known for their potential health benefits, namely due to their richness in antioxidants, vitamins and minerals. To assess consumers’ perception of red fruits purchase, conservation, preparation and consumption habits and their potential health benefits. A questionnaire was applied and distributed through e-mails and social media. From January to February of 2023, 507 individuals answered this survey. It focused on individuals’ perception of red fruits consumption and purchase habits; reasons, frequency and season of consumption; preparation and conservation procedures and potential health benefits. Among all participants, 62.7% were aged between 18-29 years, 75.3% were females and 60.4% were from Lisbon. The majority had higher education (79.6%) and a considerable number had health qualifications (36.1%). 387 participants claimed to frequently consume red fruits. Those who do not consume essentially declared high price as the main reason (60.0%). Most people purchase red fruits at super and hypermarkets (88.4%), eat them mostly fresh in spring and summer, and keep them in the fridge until consumption. Strawberry was the most frequently consumed and cranberry was the least one. Vitamins (92.1%) and anthocyanins (44.4%) were the most common substances related to red berries. 49.1% of the participants considered red fruits to be more beneficial than others, associating them with antioxidant effects (87.8%), general health and well-being (69.6%), and prevention of diseases (71.8%) like cardiovascular diseases (73.9%) and cancer (57.4%). Our findings suggest that most of this population consumes red fruits. It was verified a reasonable knowledge of their health benefits; however, several did not recognize their advantages, even having higher education. It is essential to enhance the spread of scientific information regarding the potential health benefits associated with the consumption of red fruits.
- Determinação da atividade antioxidante, compostos fenólicos e flavonoides totais em frutos vermelhos e hortícolas de folha verdePublication . Salgado, N.; Silva, M.A.; Figueira, M.E.; Costa, H.S.; Albuquerque, T.G.Atualmente, vários estudos demonstram uma relação inversa entre o consumo de frutas e hortícolas e o aparecimento de doenças crónicas não transmissíveis, devido à sua riqueza em vitaminas, minerais e antioxidantes. Apesar destes benefícios, o consumo destes alimentos continua abaixo do valor recomendado pela Organização Mundial de Saúde (400 g por dia). Foram analisadas diferentes marcas de frutos vermelhos (morangos, framboesas e mirtilos) e de hortícolas de folha verde (espinafres e alfaces), para estudar a variabilidade da atividade antioxidante e do teor de compostos fenólicos e de flavonoides totais. As amostras foram recolhidas em grandes superfícies comerciais da região de Lisboa, tendo sido adquiridas 3 marcas de cada alimento (identificadas de A a C), exceto de morangos em que foram analisadas apenas 2 marcas. Determinou-se a atividade antioxidante pelo método DPPH• e o teor de fenólicos e flavonoides totais pelos métodos Folin-Ciocalteau e de complexação de alumínio, respetivamente. No método DPPH•, os morangos B evidenciaram maior atividade antioxidante, com 21,5 ± 1,0 µmol de equivalentes de trolox (ET)/g de amostra, seguindo-se os mirtilos A e as framboesas A. Por outro lado, os hortícolas de folha verde demonstraram menor atividade antioxidante, principalmente as alfaces (0,3 – 0,8 µmol ET/g). Relativamente aos flavonoides totais, os morangos B apresentaram o maior valor (504,2 ± 17,7 mg de equivalentes de epicatequina/100 g de amostra), seguido dos espinafres A e dos mirtilos A. De entre os vários ingredientes, as alfaces B e C foram as que apresentaram menor teor de flavonoides. No que diz respeito aos fenólicos totais, evidencia-se o elevado teor em todos os frutos vermelhos analisados, destacando-se os morangos que apresentaram cerca de 500 mg de equivalentes de ácido gálhico (EAG)/100 g. A alface, entre os alimentos analisados, foi o menos rico em fenólicos (73,0 ± 6,2 – 100,1 ± 1,8 mg de EAG/100 g de amostra). De forma geral, os frutos vermelhos, principalmente os morangos B, destacam-se enquanto alimentos ricos em antioxidantes, verificando-se alguma variabilidade entre marcas do mesmo alimento, que se pode dever a diferentes práticas de cultivo, estado de maturação, variedades, características do solo, condições ambientais e de armazenamento. Contrariamente, os hortícolas analisados têm menos antioxidantes, principalmente a alface, e os resultados entre marcas mantêm-se com pouca variação.
- Effects on antioxidant activity, total phenolics and flavonoids of different mixtures of red fruits and green leafy vegetablesPublication . Salgado, N.; Silva, M.A.; Costa, H.S.; Figueira, M.E.; Albuquerque, T.G.Currently, several studies have shown an inverse relationship between fruits and vegetables consumption and the appearance of noncommunicable chronic diseases, due to their richness in vitamins, minerals and antioxidants. Despite these benefits, their consumption is still lower than recommended by the World Health Organization (400 g per day). This research intends to assess the synergistic, antagonistic and additive effects of 20 mixtures (M1-M20) of red fruits (strawberry I1, raspberry I2, and blueberry I3) and green leafy vegetables (spinach I4 and lettuce I5) in different proportions, considering their in vitro antioxidant content. Analytical methods for antioxidant activity (DPPH•), total phenolics and flavonoids were carried out in ingredients and their mixtures. For each mixture, expected values were calculated by adding the results of ingredients considering their amount and, then, compared with observed values. When significant differences were found (p < 0.05), the effects were classified as synergistic (observed value > expected value) or antagonistic (observed value < expected value). When significant differences were not found (p > 0.05), the effect was considered additive. Concerning DPPH•, the majority of the effects in mixtures were synergistic. However, M15 and M16 had antagonistic effects and M13 was the only one with additive effect. M6 (34% I2 and 34% I3) had the most highlighted synergistic interaction. Regarding total flavonoids, all mixtures presented synergistic effects, with M4 (50% I4) having the highest synergy (observed value = 331.7 mg of epicatechin equivalents/100 g of sample > expected value = 137.8 mg of epicatechin equivalents /100 g of sample) and M12 (35% I5) the lowest. When considering total phenolics, synergistic effects in all mixtures were observed, with M6 and M8 (68% red fruits) being highlighted and M5 (50% I5) having the weakest interaction. In general, most of the mixtures had synergistic interactions, which means gathering ingredients in those proportions enhances antioxidant content and, therefore, can promote health benefits. In these assays, M6 is highlighted, except on total flavonoids. Also, these mixtures can be used to reduce inadequate consumption of fruits and vegetables.
- Oxalate in Foods: Extraction Conditions, Analytical Methods, Occurrence, and Health ImplicationsPublication . Salgado, N.; Silva, M.A.; Figueira, M.E.; Costa, H.S.; Albuquerque, T.G.Oxalate is an antinutrient present in a wide range of foods, with plant products, especially green leafy vegetables, being the main sources of dietary oxalates. This compound has been largely associated with hyperoxaluria, kidney stone formation, and, in more severe cases, systematic oxalosis. Due to its impact on human health, it is extremely important to control the amount of oxalate present in foods, particularly for patients with kidney stone issues. In this review, a summary and discussion of the current knowledge on oxalate analysis, its extraction conditions, specific features of analytical methods, reported occurrence in foods, and its health implications are presented. In addition, a brief conclusion and further perspectives on whether high-oxalate foods are truly problematic and can be seen as health threats are shown.
- Study of the influence of the composition of a mixture of fruits and vegetables on the content of total phenolics, flavonoids and vitamin CPublication . Salgado, N.; Silva, M.A.; Costa, H.S.; Figueira, M.E.; Albuquerque, T.G.Low consumption of fruits and vegetables is among the top ten risk factors that contribute to global mortality. According to the World Health Organization and Food and Agriculture Organization of the United Nations, a minimum consumption of 400 g of fruit and vegetables per day (excluding starchy tubers) is recommended, in order to prevent obesity, diabetes, cancer, and cardiovascular diseases, among others. g In this study, strawberry (SA), raspberry (R), blueberry (B), lettuce (L) and spinach (SP) were selected as ingredients to prepare five mixtures, with the aim of studying the influence of the composition of the mixtures on their total phenolics, flavonoids and vitamin C contents. In May 2023, the ingredients were acquired in different commercial surfaces of Lisbon region and when applicable the non-edible portions were discarded. A portion of each ingredient was used to prepare five mixtures (M1-M5). The amount of each ingredient varied between 10 and 50 g. Total phenolics and flavonoids were determined by spectrophotometric methodology, while vitamin C was determined by high-performance liquid chromatographic coupled to photodiode array detection. M4 (50%SP; 18.8%L; 11.2%SA; 10%B; 10%R) has the highest flavonoids content (303 ± 18.4 mg of epicatechin equivalents/100 g), while M2 (50%R; 18.4%L; 11.6%SP; 10%SA; 10%B) has the highest amount of total phenolics (322 ± 26.2 mg of gallic acid equivalents/100 g). Concerning total vitamin C, the content in the analysed mixtures varied between 1.96 ± 0.04 and 9.93 ± 0.08 mg/100 g). M2 was the one with the highest total phenolics and ascorbic acid contents but it has the lowest flavonoids content. In the next steps of this research work, other analytical parameters will be studied, to evaluate which is the best formulation of the mixture for consumers, from a public health point of view.