Percorrer por autor "Santos, Alberto"
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- Analysis of phenolic compounds from hazelnut (Corylus avellana L.) leavesPublication . Amaral, Joana S.; Ferreres, Frederico; Santos, Alberto; Pinheiro, Cristina; Andrade, Paula B.; Seabra, Rosa M.Hazelnut leaf has been used in folk medicine in varicose veins and haemorrhoidal symptomatology for its vasoconstrictor and antihaemorrhagic properties. Slight antidysenteric, antifungal and healing properties have also been described
- Characterization of several hazelnut (Corylus avellana L.) cultivars based in chemical, fatty acid and sterol compositionPublication . Amaral, Joana S.; Casal, Susana; Citová, Ivana; Santos, Alberto; Seabra, Rosa M.; Oliveira, BeatrizNineteen cultivars of hazelnuts (Corylus avellana L.) collected during the 2001 crop, from Vila Real, Portugal, were analysed for chemical composition, including moisture, total oil content, crude protein, ash, carbohydrates and nutritional value. Fat was the predominant component, ranging from 59.3 to 69.0%. Total oil was extracted and analysed for fatty acid and sterol compositions and oxidative stability. Fatty acid and sterol compositions were determined by Gas–Liquid Chromatography coupled to a Flame Ionisation Detector (GLC/FID). Monounsaturated fatty acids, particularly oleic acid, were predominant (78.7–84.6%). Total phytosterol content ranged from 133.8 to 263.0 mg/100 g of oil. Among the nine sterols identified and quantified, β-sitosterol was the major one with a mean percentage of 83.6%, while Δ5-avenasterol and campesterol were the second and the third components of the group with mean values of 6.1 and 5.8%, respectively. Since hazelnut oil can be used in olive oil adulteration, the values obtained were compared with published mean values of olive oils from different geographical origins.
- Influence of cultivar and environmental conditions on the triacylglycerol profile of hazelnut (Corylus avellana L.).Publication . Amaral, Joana S.; Cunha, Sara C.; Santos, Alberto; Alves, M. Rui; Seabra, Rosa M.; Oliveira, BeatrizThe oil of several hazelnut ( Corylus avellana L.) samples was extracted and evaluated for their triacylglycerol (TAG) composition. Trials were conducted in two Portuguese localities (Vila Real and Felgueiras) during three consecutive years and involved a total of 19 cultivars. The samples were analyzed by reversed-phase high-performance liquid chromatography with evaporative light-scattering detection. Sample preparation was fast and simple, consisting only of the dissolution of the oil in acetone, homogenization, and filtration, allowing this technique to be suitable for routine analyses. All samples presented a similar qualitative profile composed of eleven compounds: LLL, OLL, PLL, OOL, POL, PPL, OOO, POO, PPO, SOO and PSO (P, palmitoyl; S, stearoyl; O, oleoyl; and L, linoleoyl). The main components were OOO, LOO, and POO, reflecting the high content of oleic acid in hazelnut oils. A total of 79 different samples were studied, and the obtained data were statistically analyzed. Significant differences were verified in canonical variate plots when cultivars were grouped by country of origin. In general, the American cultivars were richer in TAGs with saturated fatty acids moieties, and the group of French, German, and English cultivars was richer in TAGs containing linoleic acid moieties. Differences were also significant when cultivars were grouped by year of production, showing that besides genetic factors, the TAG composition can be influenced by environmental factors.
- Nutritional value and fatty acid composition of Hazelnut varieties harvested in PortugalPublication . Amaral, Joana S.; Citová, Ivana; Casal, Susana; Santos, Alberto; Seabra, Rosa M.; Oliveira, Beatriz
- Phenolic profile of hazelnut (Corylus avellana L.) leaves cultivars grown in PortugalPublication . Amaral, Joana S.; Ferreres, Frederico; Andrade, Paula B.; Valentão, Patrícia; Pinheiro, Cristina; Santos, Alberto; Seabra, Rosa M.In this study, phenolic compounds of hazelnut leaves of 10 different cultivars with the same cultural, geographical, geological and climatic conditions were analyzed by HPLC/DAD and HPLC/DAD/MS/MS – ESI. Eight phenolic compounds (3-caffeoylquinic acid, 5-caffeoylquinic acid, caffeoyltartaric acid, p-coumaroyltartaric acid, myricetin 3-rhamnoside, quercetin 3-glycoside, quercetin 3-rhamnoside and kaempferol 3-rhamnoside) were identified and quantified. All of the analyzed samples showed a similar phenolic profile, in which myricetin 3-rhamnoside and quercetin 3-rhamnoside were the major compounds and caffeoyltartaric and p-coumaroyltartaric acids were present in vestigial amounts.
- A segmentation approach for the identification of hazelnut cultivarsPublication . Rodrigues, Pedro João; Amaral, Joana S.; Santos, Alberto; Igrejas, GetúlioThe development of a methodology for cultivar discrimination and selection during on-line quality selection could be a relevant tool for certain industries that use hazelnuts as ingredients in processed food products. The aim of this work was to obtain a computer vision system that enables an automatic recognition of six hazelnuts cultivars from 3 different origins (US, Italy and Spain). To achieve this objective, an algorithm for tuning the segmentation between the hazelnut shell and crown was developed. Important morphological features that allow the correct identification of the cultivar present in an image were obtained from the segmentation process. Finally, these features were used as input data to a neural network classifier. The obtained results showed a high percentage of correct cultivar classification.