Browsing by Author "Bessada, S."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Influence of germination on the nutritional value and lipid profile of Vigna unguiculata seedsPublication . Araújo, C.; Alves, R.C.; Costa, A.S.G.; Bessada, S.; Nunes, M.A.; Benevides, C.M.J.; Albuquerque, T.G.; Costa, H.S.; Soveral, G.; Oliveira, M.B.P.P.Introduction and objectives: Legumes have high levels of protein and fiber and despite their low fat content, their lipid fraction is of high nutritional quality, contributing to a balanced diet. Moreover, when supplemented with cereals, they can be good animal protein substitutes. Objective: In this work, seeds of Vigna unguiculata in different stages – germinated, green (in natura) and dried – were compared regarding their nutritional composition and lipid profile (fatty acids and vitamin E). Materials and Methods: The content of ash, protein, fat, fiber (total and insoluble) were analysed by AOAC methods. The moisture content was determined using an infrared moisture analyser. The content of carbohydrates and soluble fiber was obtained indirectly by calculation. The fatty acid (FA) and vitamin E (tocopherols and tocotrienols) profiles were determined by chromatographic techniques (GC-FID and HPLC-DAD-FLD, respectively). Results: In a dry weight (dw) basis, no significant differences were found between protein and carbohydrate contents of the different types of seeds. However, significantly higher levels of ash (4.97%) and insoluble fiber (24.69%) were found in germinated seeds. In turn, green ones presented significantly higher levels of fat (1.58%) and soluble fiber (8.45%). Regarding vitamin E, total contents ranged from 5.2 to 10.3 mg/100 g dw. δ-Tocopherol (4.2-6.7 mg/100 g dw) was the major compound found, followed by γ-tocopherol (0.6-3.3 mg/100 g dw). Both vitamers were present in significantly higher contents in dried seeds, while α-tocopherol contents were significantly higher in germinated ones. In what concerns to the lipid profile, C16:0 (21.5-24.6%), C18:2n6 (33.5-34.7%), and C18:3n3 (22.1-26.1%) were the major FA. Some differences were noticed between the FA profiles of the different samples, being germinated seeds slightly richer in saturated FA, while dried seeds presented higher relative percentages of polyunsaturated ones. Conclusion: In general, with germination, there was a significant increase in the ash and insoluble fiber contents of the seeds, as well as modifications in the vitamin E and FA profiles. Nevertheless, the nutritional richness of the Vigna unguiculata seeds was demonstrated independently of the seed stage.
- Vitamin E in Opuntia ficus-indica (L.) Mill.: a comparative study between pulp and peelPublication . Albuquerque, T.G.; Alves, R.C.; Costa, H.S.; Silva, M.A.; Bessada, S.; Pereira, P.; Ramalho, R.; Oliveira, M.B.P.P.Vitamin E is a lipid soluble vitamin, designating a group of eight naturally occurring and structurally related vitamers, namely α-, β-, δ-, and γ-tocopherol and α-, β-, δ-, and γ-tocotrienol. α- and γ-tocopherols are the two major forms of this vitamin. The main dietary sources are vegetable oils, nuts and oilseeds. According to Regulation (EU) n.º 1169/2011, the dietary reference intake for adults is 12 mg/day. The aim of this work was to evaluate the vitamin E content in the edible portion (pulp) and by-product (peel) of Opuntia ficus-indica (L.) Mill., which are commonly known as prickly pears. Samples of prickly pears were obtained at Herdade de Peliteiros Silveiras, Montemor-o-Novo, Évora. After the separation between edible and non-edible portion, samples were homogenised and lyophilised. The chromatographic analysis of vitamin E was performed by high performance liquid chromatography. The chromatographic separation of the vitamers was achieved with a normal phase SupelcosilTM LC-SI (75 x 3.0 mm, 3 μm i.d.). A mixture of n-hexane and 1,4-dioxane (98.5:1.5) was used as eluent, at 0.7 mL/min. The detection was performed by diode array detection connected in series with the fluorescence detector (λexc: 290 nm; λem: 330 nm). The compounds were identified by comparison with standards and by their individual UV spectrum. The most abundant vitamer in both parts of the fruit was α-tocopherol, being 47.97 and 208.9 µg/g of dry weight for pulp and peel, respectively. Nevertheless, the second major compound was β-tocopherol in the peel (9.32 ± 0.64 µg/g of dry weight) and γ-tocopherol in the pulp (9.35 ± 0.64 µg/g of dry weight). Concerning tocotrienols, only α-tocotrienol was possible to be quantified, since the other vitamers were not detected. Based on the results obtained for the analysed prickly pear, it is possible to conclude that it is a good source of vitamin E and it could contribute to the intake of natural antioxidants. It is a fruit with nutritional interest and its use in human diet can bring potential health benefits to consumers. Also, due to the high amounts of vitamin E in the peel, these by-products could be added as natural extracts in cosmetic, pharmaceutical and food processing industries. Furthermore, this work will contribute to maintain the biodiversity and to promote the sustainable development and exploitation of these exotic fruits.