Percorrer por autor "Alexopoulos, Alexios"
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- Anthocyanin-rich extracts from purple and red potatoes as natural colourants: Bioactive properties, application in a soft drink formulation and sensory analysisPublication . Sampaio, Shirley L.; Lonchamp, Julien; Dias, Maria Inês; Liddle, Catriona; Petropoulos, Spyridon Α.; Glamočlija, Jasmina; Alexopoulos, Alexios; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.; Barros, LillianAqueous extracts from seven coloured potato varieties (three red-fleshed, three-purple fleshed, and one marble-fleshed) were studied for their anthocyanin content, in vitro biological activities, colouring properties and their potential application in the food industry. Acylated glycosides or pelargonidin and petunidin aglycones were identified as the main anthocyanin forms in the red and purple varieties, respectively. The total anthocyanin content among varieties ranged from 478.3 to 886.2 mg/100 g extract. All the extracts presented in vitro antioxidant, antibacterial and antifungal activities, whereas no toxic effects were detected. Finally, two selected extracts were tested as colourants in a soft drink formulation and presented suitable sensory profiles as well as high colour stability during a 30-day shelf-life when compared with the commercial colourant E163. Therefore, the tested extracts could be used as natural food colourants and considered for substituting the existing synthetic colouring agents.
- Domestication of wild edible species: the response of Scolymus hispanicus plants to different fertigation regimesPublication . Paschoalinotto, B. H.; Polyzos, Nikolaos; Compocholi, Maria; Rouphael, Youssef; Alexopoulos, Alexios; Dias, Maria Inês; Barros, Lillian; Petropoulos, Spyridon Α.Scolymus hispanicus L. is a wild edible species with wide distribution in the Mediterranean area. Recent research has focused on the domestication of wild edible greens, which is essential for the preservation of agroecosystems and the increase in biodiversity, especially under the adversely changing climate conditions. In the present work, the aim was to evaluate the response of S. hispanicus plants to different fertilization regimes that varied in the amounts of nitrogen, phosphorus and potassium in regard to plant growth and chemical composition of leaves. For this purpose, plants were grown in pots within an unheated greenhouse. Seven experimental treatments were used, including six fertigation regimes (SH1-SH6) and the control treatment (SHC), where no fertilizers were added. Fresh yield was beneficially affected by the treatments that included a high content of P and K (e.g., SH3 and SH5), while lesser amounts of these macronutrients (e.g., SH1 and SH4) resulted in higher chlorophyll content (SPAD index) and leaf area. In terms of mineral profile, high amounts of P and K improved dietary fiber and carbohydrates content, whereas the untreated plants had the highest content of ash, fat and crude protein. Oxalic and quinic acid were the major organic acids detected, with fertigation regimes significantly reducing their content compared to the control treatment. α-tocopherol was the only isoform of vitamin E detected in all the samples, while glucose and fructose were the most abundant sugars, with their highest content detected in control and SH4 treatments, respectively. Scolymus hispanicus leaves were rich in macro and micro minerals, while their contents varied depending on the fertigation regime. Finally, α-linolenic, palmitic, and linoleic acid were the major fatty acids detected, while their contents were beneficially affected by low nutrient inputs (e.g., untreated plants and SH1 and SH2 treatments). In conclusion, the regulation of nutrient solution seems to be an effective practice to increase fresh yield in S. hispanicus without compromising the nutritional profile of the edible product, while low inputs of macronutrients such as P and K may improve the chemical composition of the species, especially in terms of n-fatty acids.
- Nutritional and antioxidant characterization of the peel of 10 species of coloured potatoesPublication . Oliveira, Izamara; Rodrigues, Christian Teixeira; Heleno, Sandrina A.; Petropoulos, Spyridon Α.; Alexopoulos, Alexios; Carocho, Márcio; Ferreira, Isabel C.F.R.; Barros, LillianThe use of by-products from the food agro-industry reduces production costs, increases the total use of food and reduces the impact that these by-products may cause when disposed of in the environment. In this way, some potato by-products are used and transformed into food ingredients, such as peelings. Thus, innovative measures are needed to stimulate the full reuse of these foodstuffs, since, whenever possible, the final waste should become raw material for a new process, constituting a second transformation, leading to the reuse of all the raw materials of the potato industry. In this sense, the aim of this work was to carry out a study aimed at peeling ten potato species to which the nutritional parameters were carried out. The samples were from different countries, grown in Greece and obtained under optimal consumption conditions. A total nutritional characterization of the twenty-nine potato peels was performed, as well as of the individual organic acids and soluble sugars. The antioxidant activity was carried out using the thiobarbituric acid reactive substances (TBARS) assay. According to the results obtained, the sample Peru Blue (1.57 ± 0.05 g/100g) obtained the highest value for crude fat, followed by Blaue Hindelbank (1.12 ± 0.13 g/100g); while the sample Blaue Hermans Blaue presented the lowest value (0.33 ± 0.01 g/100g). For protein, Fleuer Bleue (9.5 ± 0.2 g/100g), Blaue Hindelbank (8.9 ± 0.1 g/100g), Pink of Bolivia (9.3 ± 0.5 g/100g), Purple from Congo or Congo (8.9 ± 0.6 g/100g) and Blue from Peru (9.1 ± 0.3 g/100g) were not significantly different from each other and showed the lowest value, while Highland Burgundy Red (12.6 ± 0.1 g/100g) showed the highest value. The ash content showed statistical differences among the results, with the highest content found in Pink of Bolivia (8.0 ± 0.2 g/100g) and the lowest for Fleuer Bleue (1.3 ± 0.1 g/100g). In terms of energy there was also a difference between the results with lower values for Pink of Bolivia (373 ± 1 Kcal) and Purple from Congo (375.8 ± 0.4 Kcal) and higher for Fleuer Bleue (398 ± 1 Kcal). Two soluble sugars were identified and quantified, namely fructose and glucose. For fructose the values were highest for Fleuer Bleue (3.29 ± 0.11 g/100g) and lowest for Highland Burgundy Red (0.04 ± 0.02 g/100g), also, glucose showed lower values compared to fructose, the lowest content being quantified for Purple Fiesta (0.516 ± 0.052 g/100g) and the highest for Blue from Peru (1.07 ± 0.07 g/100g). Three organic acids were quantified, namely oxalic, malic and citric acids. Oxalic acid was highest for Hermans Blaue (2.394 ± 0.015 g/100g) and lowest for Purple Fiesta (0.91 ± 0.02 g/100g). Malic content was found highest for Purple Fiesta (3.12 ± 0.017 g/100g) and lowest for Purple from Congo or Congo (0.213 ± 0.003 g/100g DW). For citric acid, two potato samples showed higher values, namely Purple Fiesta (2.8 ± 0.2 g/100g) and Blaue Hindelbank (2.9 ± 0.1 g/100g) and two other potato samples showed lower values, namely Highland Red Fiesta (1.53 ± 0.03 g/100g) and Blaue Hermans (1.57 ± 0.01 g/100g). The antioxidant activity carried out using TBARS showed similar values for five of the 10 potatoes analysed, Highland Burgundy Red (343.4 ± 8.7 μg/mL), Violet Queen (328.4 ± 11.9 μg/mL), Purple Fiesta (305.7 ± 8.0 μg/mL), Blaue Hindelbank (366. 7 ± 12. 7 μg/mL), Pink of Bolivia (369.5 ± 12.7 μg/mL) and Blue from Peru (323.7 ± 3.5 μg/mL) showed the lowest EC50 concentrations while Blue Star (740.9 ± 33.9 μg/mL) and Fleuer Bleue (692.1 ± 13.3 μg/mL) showed the highest concentrations. This work showed that potato peel has an interesting nutritional profile and can be used to enrich other foods. Furthermore, future work will be carried out on antimicrobial activities, and cytotoxicity.
- Nutritional characterization, ph and antioxidant activity of the pulp of 29 color-fleshed potatoesPublication . Oliveira, Izamara; Rodrigues, Christian Teixeira; Heleno, Sandrina A.; Petropoulos, Spyridon Α.; Alexopoulos, Alexios; Carocho, Márcio; Ferreira, Isabel C.F.R.; Barros, LillianPotatoes (Solanum tuberosum L.) is one of the most important food sources for humans due to their high production and nutritional quality, allowing various culinary uses, from domestic cooking to processing into chips and other ready-to-eat snacks. In this work, 29 color-fleshed varieties of potatoes were studied by analyzing their pH, nutritional profile (moisture, nutritional contents of fat, protein, carbohydrates and ash) and antioxidant activity through the thiobarbituric reactive acid substances (TBARS) assay. The samples were classified by a one-way analysis of variance using Tukey's test as post-hoc analysis for homoscedastic samples and Tamhane T2 for no homoscedastic ones, using a significance of 0.05 in both cases. According to the results obtained for nutritional values, protein showed statistically significant differences, with the Lilly Rose variety having the lowest content (1.173 g/100 g) and Highland Burgundy Red having the highest protein content (2.813 g/100 g). Considering crude fat, no significant differences were sought between the 29 varieties. The ash content showed significant differences among varieties, with Lilly Rose having the lowest content (0.509g /100 g) and Highland Burgundy Red having the highest content (1.9 g/100 g). For total carbohydrates few significant differences were detected, with variations being sought only for Blaue Ajanhuiri (13.835 g/100 g) and Highland Burgundy Red (23.302 g/100 g). Moisture was classified in three significantly different groups with Highland Burgundy Red showing the lowest moisture content at 71.86 g/100 g and Lilly Rose the highest, at 83.163 g/100 g. The pH analysis showed statistical variations among the varieties, with the Blaue Neuseeländer having the lowest pH value (pH=5.839) and the Blaue St. Galler the highest (pH=6.331). For the TBARS assay, only the five potatoes (pulp) with highest antioxidant activity were selected for analysis, and, apart from Schwarzer Teufel, the rest of the four potatoes cultivars showed no significant differences among each other. The antioxidant activity (EC50) of Schwarzer Teufel was 0.37 mg/mL Overall, the results showed a similarity in nutritional values among the tested potato varieties, indicating that beyond their interesting and appealing colors, they also possess valuable nutritional parameters with low variations among the varieties. Furthermore, the Schwarzer Teufel variety showed a very high antioxidant activity compared to the rest of the tested cultivars. Further studies are being performed to analyze the color of these potatoes, as well as bioactivities and chemical composition analyses of their pulp and skin.
- Perfil nutricional e actividade antioxidante da polpa de 29 batatas coloridasPublication . Oliveira, Izamara; Rodrigues, Christian Teixeira; Heleno, Sandrina A.; Petropoulos, Spyridon Α.; Alexopoulos, Alexios; Carocho, Márcio; Ferreira, Isabel C.F.R.; Barros, LillianNeste trabalho realizou-se um estudo de 29 variedades de batatas coloridas através das análises do pH e perfil nutricional (humidade, gordura, proteínas, hidratos de carbono, cinzas), e ainda a sua atividade antioxidante através do ensaio de inibição da peroxidação lipídica de substâncias reativas ao ácido tiobarbitúrico (TBARS).
- Phenolic composition and cell-based biological activities of ten coloured potato peels (Solanum tuberosum L.)Publication . Sampaio, Shirley L.; Petropoulos, Spyridon Α.; Dias, Maria Inês; Pereira, Carla; Calhelha, Ricardo C.; Fernandes, Ângela; Leme, Camila M.M.; Alexopoulos, Alexios; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.; Barros, LillianThe present study provides an in-depth characterisation of the non-anthocyanin and anthocyanin phenolic compounds of potato peels from ten coloured potato varieties. Furthermore, the underexplored bioactive potential (antioxidant, cytotoxic and anti-inflammatory capacities) of the studied peels is comprehensively analysed. Among non-anthocyanin phenolics, caffeic and a caffeoylquinic acid were found in the highest concentrations in all samples, which also showed the presence of O-glycosylated flavonol derivatives and polyamine derivatives. Acylated anthocyanins were identified in red and purple varieties, being pelargonidin, peonidin, and malvidin the most prominent aglycones. All samples revealed antioxidant and antitumor activities, and no toxic effect. The extract of the Rosemary variety presented the best antioxidant and antitumor outcomes and was the only sample to reveal anti-inflammatory activity. These results are valuable for the food-industry by adding value to an important bio-residue, particularly concerning its potential as natural ingredients in novel food and pharmaceutical formulations.
- Physical properties of 29 colored potato varietiesPublication . Oliveira, Izamara; Ueda, Jonata Massao; Rodrigues, Christian Teixeira; Heleno, Sandrina A.; Petropoulos, Spyridon Α.; Alexopoulos, Alexios; Carocho, Márcio; Barros, Lillian; Ferreira, Isabel C.F.R.The use of different varieties of potatoes ( Solanum tuberosum L.) with different colors may be appealing to consumers, namely in terms of their visual appearance, allowing their use as “chips” and other ready-to-eat snacks. This work studied the physical properties of 29 varieties of colored potatoes, analyzing their external color and the different dimensions of texture. The external color was measured with a portable colorimeter, analyzing the CIELab color space according to the L* (lightness), a* (red-green) and b* (blue-yellow) coordinates. The texture was determined using a “texture profile analysis” assay allowing the classification of their hardness, adhesiveness, springiness, cohesiveness and resilience. The samples were classified through an analysis of variance using Tukey’s test as a post-hoc, and finally were subjected to a linear discriminant analysis for further discrimination based on the studied parameters. According to the obtained results, the color of the potatoes showed significant statistical differences, although many of the samples were related to each other. The sample with the darkest color was “Blaue veltlin” variety, with an L* of 27.8, whereas the sample with the lightest colour was “Blaue ajanhuiri” variety. In terms of the values of parameter a* the cultivar with the greenest tone was also the “Blaue ajanhuiri”, while the one closer to the red quadrant was "Purple from Peru”. Finally, the analysis of parameter b* showed that “Blaue Neuseeländer” sample was the one with the highest blue tone and “Purple fiesta” the one with the highest intensity of yellow. Regarding the different texture dimensions, the samples showed homogenous values. All samples revealed no statistical difference for springiness, whereas regarding adhesiveness, the sample “Purple from Congo” was the most adhesive at -144 g/sec and “Linzer blaue” the less adhesive at -15 g/sec. Concerning the hardness parameter, “Blaue Anneliese” and “Blaue neuseeländer” were the samples with the hardest and softest texture, respectively. In addition, the most cohesive sample was “Pink from Bolivia”, whereas the least cohesive one was “Linzer blaue”. Chewiness had three different levels of significant difference with “Blaue Anneliese” being the least chewy and “Black princess” the most, while for resilience, the least resilient were “Pink from Bolivia” and “Hermanns blaue” and the most resilient was “Linzer blaue”. In terms of the linear discriminant analysis, the first two of five functions described 84.8% of variability (function 1 – 72.0%, function 2 – 12.8%), while the varieties that presented the highest variability were “Lilly rose”, “Red salad potato”, “Purple from Peru”, “Königspurpur” and “Highland burgundy”. In conclusion, the presented results showed a great variability among the tested potato varieties indicating that these could dictate the different uses of the final food product.
- Potato biodiversity: a linear discriminant analysis on the nutritional and physicochemical composition of fifty genotypesPublication . Sampaio, Shirley L.; Barreira, João C.M.; Fernandes, Ângela; Petropoulos, Spyridon Α.; Alexopoulos, Alexios; Santos-Buelga, Celestino; Ferreira, Isabel C.F.R.; Barros, LillianFifty potato genotypes from twenty-four different countries of origin, four different flesh colours (yellow, purple, red and marble) and different cultivation types (Andean accessions, landraces, breeder lines and cultivated varieties) were studied in terms of their nutritional and physicochemical characteristics. In general, cultivated varieties and breeder lines showed the highest similarity (slight differences only in some particular fatty acids distributions: C10:0, C12:0 and C22:0) concerning the physicochemical parameters assayed in this work, independently of the geographical origin or tuber flesh colour of these genotypes. Nonetheless, some of the studied landraces and Andean accessions proved to be similar enough to be considered as genotypes with good potential for commercial cultivation. These results can contribute to the supply of new potato genotypes into sustainable farming systems, supporting the protection of potato biodiversity, particularly Andean accessions, landraces and coloured genotypes (red or purple flesh) which are not widely cultivated so far.
- The powerful Solanaceae: food and nutraceutical applications in a sustainable worldPublication . Añibarro-Ortega, Mikel; Pinela, José; Alexopoulos, Alexios; Petropoulos, Spyridon Α.; Ferreira, Isabel C.F.R.; Barros, LillianThe Solanaceae family is considered one of themost important families among plant species because, on one hand encompassesmany staple food crops of the human dietwhile, on the other hand, it includes species rich in powerful secondary metabolites that could be valorized in medicine or drug formulation as well as nutraceuticals and food supplements. Themain genera are Solanum, Capsicum, Physalis, and Lycium which comprise several important cultivated crops (e.g., tomato, pepper, eggplant, tomatillo, and goji berry), as well as genera notable for species with several pharmaceutical properties (e.g., Datura, Nicotiana, Atropa, Mandragora, etc.). This chapter discusses the nutritional value of the most important Solanaceae species commonly used for their edible fruit, as well as those used in the development of functional foods, food supplements, and nutraceuticals due to their bioactive constituents. The toxic and poisonous effects are also discussed aiming to highlight possible detrimental consequences due to irrational use. Finally, considering the high amount of waste and by-products generated through the value chain of the main crops, the sustainable management practices implemented so far are presented with the aim to increase the added-value of these crops.