Baobab: uma fonte natural de vitamina C

Introdução: As vitaminas distinguem-se de outros constituintes dietéticos por, em quantidades mínimas, beneficiarem diversos processos metabólicos. A vitamina C (ácido L-ascórbico), presente em frutas e legumes, é fundamental para a nutrição humana, por ser um antioxidante natural. No entanto, os teores do ácido L-ascórbico, principal forma biologicamente ativa desta vitamina, decrescem significativamente ao longo do amadurecimento dos alimentos. O conhecimento da composição nutricional e fitoquímica de frutos exóticos, caso da múcua (Baobab), pode dar a conhecer novas fontes de bioativos e permitir a sua valorização, contribuindo para a sustentabilidade social e económica da região de origem. Objetivos: Análise quantitativa do teor total de vitamina C da polpa do fruto da Adansonia digitata L., conhecida Baobab, espécie nativa de África. Métodos: O teor de ácido ascórbico foi determinado por HPLC-DAD, segundo um método previamente validado. 2 g de amostra foram adicionados a 12 mL de solução estabilizadora (ácido perclórico 10%, v/v) + ácido metafosfórico 1%, p/v). Para a determinação do teor de vitamina C total, utilizou-se tris(2-carboxietil) fosfina (5 mM). O teor de ácido desidroascórbico (forma biologicamente menos ativa) foi determinado por diferença. Resultados: O teor total de vitamina C foi de 26,1 mg/100 g, sendo 22,8 mg/100 g de ácido L-ascórbico e 3,33 mg/100 g de ácido desidroascórbico. Embora estes valores sejam significativamente inferiores aos descritos na laranja (49,1 mg/100 g) e no kiwi (55,2 mg/100 g), este fruto tem um período de conservação substancialmente maior. Atendendo aos seus teores reduzidos de humidade, o Baobab pode ser uma alternativa natural rica em antioxidantes. Conclusões: Este estudo salienta o potencial efeito antioxidante de uma fruta tropical pouco estudada e apenas consumida pela população local. A estabilidade do teor de ácido L-ascórbico observada no Baobab promove novas perspetivas de exploração e utilização de recursos naturais, no âmbito das ciências da nutrição

Chemical and antioxidant profiles of acorn tissues from Quercus spp.: Potential as new industrial raw materials

The bioactivity of different organs and tissues of Quercus spp. (Fagaceae), an important group of evergreen or deciduous trees from temperate and tropical climatic areas, represents a good starting point for possible industrial applications. Nevertheless, Quercus fruits, generally known as acorns, are currently undervalued and underexploited. Accordingly, the proximate composition, fatty acids and tocopherols profiles, chlorophyll, lycopene and ß-carotene contents, as well as the antioxidant activity, were studied in different Quercus species to boost new applications in food, cosmetic and pharmaceutical industries. In general, significant differences were found among the nutritional parameters, fatty acids and tocopherols contents and bioactivity indicators, either considering phenotypic (studied species) or botanical (acorn tissues) factors. The acorn tissues and the Quercus species that optimize the production of each nutrient and bioactive compound, as well as that allowing the highest antioxidant activity were thoroughly identified. The obtained information provides an increased knowledge to define potential industrial applications for acorn tissues, potentially offering economic advantages to this underutilized natural resource.The authors are grateful for the financial support to REQUIMTE/LAQV (UID/QUI/50006/2013 – POCI/01/0145/FEDER/007265) and CIMO (UID/AGR/00690/2013) from FCT/MEC through national funds and co-financed by FEDER, under the Partnership Agreement PT2020. J.C.M. Barreira thanks FCT, POPH-QREN and FSE for his grant (SFRH/BPD/72802/2010).info:eu-repo/semantics/publishedVersio

Valorization of Laurus sp. leaves as promising source of antioxidants for processed food products

Laurus sp. leaves are frequently used in Mediterranean recipes as an aromatic/flavoring ingredient. Three species of Lauris sp. have been identified as authochthonous plants in Portugal (mainland and archipelagos): L. nobilis, L. azorica, and L. novocanariensis. Scarce information exists about autochthonous Laurus sp. collected in Portugal, usually consumed in the Portuguese diet.info:eu-repo/semantics/publishedVersio

Comparison of the nutritional value of fresh and freeze-dried elephant foot yam (Amorphophallus paeoniifolius (Dennst.) Nicolson) tuber

Yams are members of different families, like Dioscoreae, Colocasia, Alocasia and Xanthosoma (Aracea) and are one of the oldest plants known. Elephant foot yam (Aracea) tuber has a great interest in food shortage periods for several populations.info:eu-repo/semantics/publishedVersio

Nutritional value and fatty acid profile from acorns (Quercus nigra): intending new alternative applications

The development of rural areas depends on sustainability policies to promote agricultural and production systems, in order to increase those populations’ income. To attain this purpose, it is important to find new opportunities to valorize the available, but still underexploited, natural resources. Therefore, the aim of this study was to compare the nutritional profile of kernel, shell and the whole fruit of Quercus nigra, a Portuguese autochthonous acorn species, intending new alternative applications (functional foods). Nutritional parameters (ash, fat, protein and moisture) were measured according to AOAC methods. Total carbohydrates were calculated by difference. The fatty acid profile was also evaluated by GC/FID.info:eu-repo/semantics/publishedVersio

Dietary supplements for cognitive function improvement: control of amino acid levels

Neurodegenerative diseases affect cognitive functions by progressive and irreversible destruction of brain cells. The medical treatment is often complemented with dietary supplementation in order to suppress the lack of nutrients that is common in these situations. Some amino acids are especially important to prevent or delay the progress of such diseases. For example, tryptophan, tyrosine, and phenylalanine are biosynthetic precursors of important neurotransmitters (serotonin, dopamine, and norepinephrine), and glutamate and aspartate are themselves brain neurotransmitters. The aim of this study was to evaluate the amino acids composition of commercial dietary supplements (n=8) for improvement of memory and cognitive function.info:eu-repo/semantics/publishedVersio