Browsing by Issue Date, starting with "2023-07-13"
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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.
- 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.