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- Antioxidant activity and chemical composition of Cichorium spinosum L. in relation to nitrogen ratePublication . Petropoulos, Spyridon Α.; Fernandes, Ângela; Karkanis, Anestis; Ntatsi, Georgia; Barros, Lillian; Ferreira, Isabel C.F.R.In the present study, the effect of nitrogen (N) application rate on phenolic compounds content and antioxidant activity of Cichorium spinosum L. leaves was examined. Seeds were sown in seed trays containing peat and young seedlings were transplanted in 2-L plastic pots containing soil. Four nitrogen rates were applied, namely: a) control (no added N), b) 200 mg L-1 of total N, c) 400 mg L-1 of total N, and d) 600 mg L-1 of total N. Plants were harvested when rosettes reached marketable size. The results showed that the most abundant phenolic compounds of leaves extracts were chlorogenic acid, chicoric acid and kaempferol-3-O-glucuronide, while increasing nitrogen rates resulted in a significant decrease of the main phenolic compounds content. Similarly, the application of 600 mg L-1 of total nitrogen resulted in significant decrease of antioxidant potency of leaf extracts comparing to control, regardless of the performed assay, whereas for all the assays except for DPPH the application of 200 mg L-1 showed the best antioxidant properties. In conclusion, although the application of high nitrogen rates is tempting in order to achieve higher yields, rates higher than 200 mg L-1 are not recommended for C. spinosum cultivation, since a significant decrease of the bioactive compounds is observed that could compromise the quality of the final product.
- Cebola "Vatikiotiko” nativa da Grécia: composição química e nutricional.Publication . Fernandes, Ângela; Petropoulos, Spyridon Α.; Ntatsi, Georgia; Barros, Lillian; Ferreira, Isabel C.F.R.‘‘Vatikiotiko’’ é uma cultivar de cebola autóctone da Grécia com características singulares de qualidade, tais como o sabor forte e picante e possui uma elevada durabilidade durante o armazenamento. O cultivo é realizado de acordo com as práticas tradicionais originárias de tempos medievais e transferido de geração em geração [1]. Na Primavera, é dos primeiros produtos que se comercializam no mercado Grego e tem, deste modo, uma grande importância cultural para a região. O seu peculiar sabor e aroma, devido às condições microclimáticas da região, tornam este produto de elevada qualidade e com potencial de exportação para os mercados estrangeiros com a denominação “Produzido na Grécia”, ou com uma Denominação de Origem Protegida (DOP) e/ou ainda um produto com Indicação Geográfica Protegida (IGP) [2]. O objetivo deste trabalho foi analisar a composição química da cultivar ''Vatikiotiko'' comparativamente com cultivares híbridas de cebolas comerciais, nomeadamente, “Red Cross F1”, “Sivan F1” e “Creamgold”, dando especial enfoque ao valor nutricional, e composição em açúcares, tocoferóis e ácidos gordos. Os bolbos das cebolas foram colhidos, na primeira quinzena do mês de junho de 2014, na região de Vatika (Grécia), seguindo-se 2 semanas de maturação. Foi determinada a humidade, proteínas, lípidos, glúcidos e cinzas segundo os procedimentos analíticos padronizados. Açúcares e tocoferóis foram determinados por cromatografia líquida de alta eficiência acoplada a um detetor de índice de refração e de fluorescência, respetivamente; os ácidos gordos foram determinados por cromatografia gasosa acoplada a um detetor de ionização de chama. O valor nutricional das cebolas “Vatikiotiko” foi elevado comparativamente com as cultivares comerciais. Os açúcares totais, bem como a frutose e a glucose foram menores nas cultivares “Vatikiotiko” e “Creamgold”. Os ácidos gordos saturados e monoinsaturados foram detetados em iguais quantidades nas amostras de “Vatikiotiko”. O presente estudo na cultivar “Vatikiotiko” permite sustentar as suas qualidades especiais, nomeadamente em termos de valor nutricional, e a necessidade de revalorizar e proteger a sua cultura tradicional.
- Chemical composition and antioxidant activity of Cichorium spinosum L. leaves in relation to developmental stagePublication . Petropoulos, Spyridon Α.; Fernandes, Ângela; Antoniadis, Vasileios; Ntatsi, Georgia; Barros, Lillian; Ferreira, Isabel C.F.R.In the present study, chemical composition and bioactivity of Cichorium spinosum leaves were examined at different growth stages for optimum harvest stage and end-use assessment. Total fresh weight and number of leaves were higher at 4th growth stage; however, at this stage the end-use is not indicated for raw consumption but mostly for pickled or dried products. Regarding chemical composition, the highest content of tocopherols and minerals was observed in the 1st growth stage, whereas sugars content was the highest in 3rd and 4th growth stage. Polyunsaturated fatty acids content was the highest during the first two growth stages, whereas antioxidant activity, phenolic acids and total phenolic compounds content in the 3rd stage. In conclusion, the results of this study indicate that chemical composition of C. spinosum is highly depended on development stage, and harvest stage should be considered for alternative uses of end-products with high bioactivity.
- Chemical composition and yield of six genotypes of common purslane (Portulaca oleracea L.): an alternative source of omega-3 fatty acids.Publication . Petropoulos, Spyridon Α.; Karkanis, Anestis; Fernandes, Ângela; Barros, Lillian; Ferreira, Isabel C.F.R.; Ntatsi, Georgia; Petrotos, Konstantinos; Lykas, Christos; Khah, EbrahimCommon purslane (Portulaca oleracea L.) is an annual weed rich in omega-3 fatty acids which is consumed for its edible leaves and stems. In the present study six different genotypes of common purslane (A-F) were evaluated for their nutritional value and chemical composition. Nutritional value and chemical composition depended on genotype. Oxalic acid content was the lowest for genotype D, whereas genotypes E and F are more promising for commercial cultivation, since they have low oxalic acid content. Genotype E had a very good antioxidant profile and a balanced composition of omega-3 and omega-6 fatty acids. Regarding yield, genotype A had the highest yield comparing to the other genotypes, whereas commercial varieties (E and F) did not differ from genotypes B and C. This study provides new information regarding common purslane bioactive compounds as affected by genotype and could be further implemented in food industry for products of high quality and increased added value.
- Effect of ammonium fertilizer on growth and quality of Cichorium spinosum plantsPublication . Anesti, Stavroula; Fasoli, Konstantina; Petropoulos, Spyridon Α.; Ntatsi, Georgia; Antoniadis, Vasileios; Ferreira, Isabel C.F.R.In the present study, the effect of ammonium fertilizer rate on plant growth and quality of Cichorium spinosum L. was examined. Five fertilizer treatments were applied regarding the ammonium nitrogen percentage of total nitrogen, namely (1) 14%, (2) 24%, (3) 34%, (4) 43%, and (5) 53% of total nitrogen applied in the form of ammonium nitrogen. All the treatments received the same total nitrogen rate. Seeds of C. spinosum were sown in seed trays containing peat, and young seedlings were transplanted in 2L pots containing peat and perlite in a ratio 1:1. Plants were harvested twice during growing period and when rosettes reached the marketable size. On the harvest days, plant features regarding plant development (the number of leaves, the fresh and dry weight of leaves, and rosette diameter), as well as quality mineral composition, SPAD index of leaves) were recorded. From the results it is suggested that fertilizer composition had a significant effect on plant growth and quality. In particular, fresh weight for both harvests, as well total fresh weight were higher in treatments 4 and 5, where 43 and 53% of the total nitrogen was applied as ammonium nitrogen. Dry weight did not differ significantly in the first harvest, while in the second harvest treatment 1 had the lowest dry weight. Diameter and number of leaves were the lowest in treatments 2 and 3, respectively, while significant differences were also observed between treatments regarding the quality features.
- Effect of storage on quality features of local onion landrace ‘Vatikiotiko’Publication . Petropoulos, Spyridon Α.; Fernandes, Ângela; Barros, Lillian; Barreira, João C.M.; Ntatsi, Georgia; Antoniadis, Vasileios‘Vatikiotiko’ is a Greek landrace of Allium cepa L. of the Liliaceae family, cultivated only in the region of Vatika, in Lakonia prefecture as a short day onion. The dry bulbs are a quality product highly sought after in Greek market, since this is the earliest onion that comes out during Spring. However, so far the production is limited and the potential of this landrace is not fully developed. In the present study we examined the effect of storage at two temperatures (23±1 and 5±1°C) and 60-70% RH (relative humidity) on marketability and quality features of dry bulbs of ‘Vatikiotiko’ landrace and ‘Sivan F1’ which is also cultivated in the specific region. The experiments were carried out at the University of Thessaly, Greece during the period 2014-2015. The quality features that were recorded during storage included fresh weight loss, bulb firmness, antioxidants and sugar’s composition. The measurements were taken at regular intervals and the storage was completed when either bulbs had not marketable quality or sprouting occurred. So far the results have shown that ‘Vatikiotiko’ onion can be stored for 7 months at both temperatures, whereas at 5±1°C storage could be prolonged for almost 8 months without significant marketability and quality loss. Similarly, ‘Sivan F1’ sprouting occurred after 5 and 6 months at 23±1 and 5±1°C, respectively. Therefore, the fact that ‘Vatikiotiko’ landrace is a storage onion allows for further valorization in order to increase total production and yield, since the stored product could cover the market needs that arise throughout the year, whereas breeding is needed in order to minimize the genetic variability of the landrace and increase uniformity of the final product.
- Effect of storage on quality features of local onion landrace (vatikiotiko)Publication . Petropoulos, Spyridon Α.; Fernandes, Albano M.; Barros, Lillian; Ferreira, Isabel C.F.R.; Ntatsi, Georgia"Vatikiotiko" is a Greek landrace of Allium cepa L. of the Alliaceae family, cultivated only in the region of Vatika, in Lakonia prefecture as a short day onion. The dry bulbs are a quality product highly sought after in Greek market, since this is the earliest onion that comes out during spring. However, so far the production is limited and the potential of this landrace is not fully developed. In the present study we examined the effect of storage at two temperatures (25± 1 and 5±1 °C and 60-70% RH) on marketability and quality features of dry bulbs of "Vatikiotiko" landrace and "Si van F 1" which is also cultivated in th e specific region. The experiments were carried out at the University of Thessaly, Greece during the period 20 14-2015. The quality features that were recorded during storage included fresh and dry weight of bulbs, fresh weight loss, color of tunic and flesh, nutritional value and mineral composition. The measurements were taken at regular intervals and the storage was completed when either bulbs had not marketable quality or sprouting occurred. So far the results have shown that "Vatikiotiko" onion can be stored for at least five months at 25± i °C, whereas at 5±1 C storage could be prolonged for almost 8 months without significant marketability and quality loss, whereas for "Si van Fl" sprouting occurred after 5 and 6 months at 25±1 and 5±1 ac respectively. Threfore, the fact that "Vatikiotiko" landrace is a "storage" onion allows for further exploitation in order to increase total production and yield, since the storaged product could cover the market needs that arise throughout the year, whereas breeding is needed in order to minimize the genetic variability of the landrace and incrase uniformity of the final product.
- Estudo da composição química de seis genótipos de Portulaca oleracea L.Publication . Fernandes, Ângela; Petropoulos, Spyridon Α.; Karkanis, Anestis; Barros, Lillian; Ntatsi, Georgia; Petrotos, Konstantinos; Lykas, Christos; Khah, Ebrahim; Ferreira, Isabel C.F.R.Portulaca oleracea L. (vulgarmente designada por beldroega) é uma erva daninha cujas partes aéreas são comestíveis, sendo consumidas cruas, em saladas ou cozidas [1]. Existe uma variação genética significativa entre os genótipos de beldroegas [2], e esta diversidade pode ser utilizada no desenvolvimento de cultivares de alto rendimento com elevado conteúdo em ácidos gordos ómega-3, por exemplo. O objetivo deste trabalho foi analisar a composição química de seis genótipos de beldroega: três ecótipos silvestres provenientes do mar Cáspio da região do Irão (genótipo A, B e C: das cidades de Sari, Gorgan e Aliabad, respetivamente), uma variedade local proveniente da região de “Domokos” na Grécia central (genótipo D) e duas cultivares comerciais beldroega comum de Gemma S.A. (genótipo E) e beldroega verde escura (genótipo F). Os açúcares foram determinados por cromatografia líquida de alta eficiência (HPLC) acoplada a um detetor de índice de refração; os ácidos orgânicos foram analisados por HPLC acoplada a um detetor de fotodíodos e os ácidos gordos por cromatografia gasosa acoplada a um detetor de ionização de chama. Verificou-se que a composição química de beldroegas é dependente do genótipo. O teor em açúcares totais foi mais elevado no genótipo B; o teor em ácido oxálico foi menor no genótipo D e maior no genótipo C. Os ácidos gordos mais abundantes foram o ácido palmítico (C16:0), o ácido oleico (C18:1), o ácido linoleico (C18:2n6) e o ácido alfa-linolénico (C18:3n3), com diferenças significativas nos teores presentes nos diferentes genótipos avaliados. O genótipo D apresentou maior percentagem relativa do ácido alfa-linolénico. O genótipo E revelou possuir uma composição equilibrada de ácidos gordos ómega-3 e ómega-6. As variedades comerciais (genótipos E e F) foram bastante similares aos genótipos B e C. Este estudo fornece novas informações sobre a composição química de beldroegas que podem ser utilizadas na indústria alimentar como produtos de elevada qualidade e valor acrescentado. Assim, estas plantas devem ser valorizadas, nomeadamente como uma fonte de ácidos gordos ómega-3.
- Evaluation of various ecotypes of “stamnagathi’ (Cichorium spinosum L.)Publication . Caroussou, D.; Petropoulos, Spyridon Α.; Levizou, Efi; Fernandes, Ângela; Barros, Lillian; Barreira, João C.M.; Ferreira, Isabel C.F.R.; Ntatsi, GeorgiaIn the present study, the evaluation of chemical composition of various ecotypes of “stamnagathi” (Cichorium spinosum L.) was carried out. Seeds from selected ecotypes were collected in situ and sown in seed trays for plant propagation and consequent plant production. At the harvest stage, the dry matter, chlorophyll, sugars, fatty acids and organic acids content in leaves was measured. Regarding dry matter content, significant differences were observed among the ecotypes, with mean values ranging from 6.3 to 8.3%. Differences were also observed in chlorophyll a, b and total chlorophyll, with ecotypes B and D having the highest content comparing to ecotypes A and C. Sugars content differed among the ecotypes for all the detected sugars (glucose, fructose, sucrose) and the total sugars content. Ascorbic acid was detected only in the case of ecotypes B and C, whereas in the other two ecotypes only traces were detected. Finally, regarding tocopherols content, significant differences were observed for both α- tocopherol, with ecotype B having the highest content followed by ecotype C, and δ- tocopherol, where the highest content was observed for ecotype C. For total tocopherols, ecotype C had also the highest content comparing to the other ecotypes. Fatty acids content did not differ among the studied ecotypes, for both the content of the main fatty acids (α-linolenic, linoleic and palmitic acid) and the monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) and total fatty acids (TFA) content. In conclusion, genotype has an important effect on nutritional and chemical composition of ‘stamnagathi’ ecotypes, and special interest rises for detecting and evaluating ecotypes with high quality profile for commercial cultivation.
- Harvesting time affects yield and chemical composition of Cichorium spinosum L.Publication . Petropoulos, Spyridon Α.; Fernandes, Ângela; Karkanis, Anestis; Ntatsi, Georgia; Barros, Lillian; Ferreira, Isabel C.F.R.In the present study, the eff ect of the number of harvests on yield and chemical composition of Cichorium spinosum L. plants was examined. Seeds of were sown in seed trays containing peat and young seedlings were transplanted in 2L pots containing peat and perlite (1:1 v/v). Plants were harvested two or three times during the growing period, while control plants (no prior harvests) were also harvested at the same time. Rosette diameter, number of leaves, SPAD index, and fresh and dry weight were recorded at harvest, while chemical composition of leaves was also assessed (fatty-acids, sugars, organic acids, and tocopherols content). Regardless of the number of harvests, total fresh weight and number of leaves were higher comparing to control plants, whereas dry weight and rosette diameter were higher in control plants. SPAD index was mostly aff ected by harvesting time (growth stage) and decreased during the growing season. Signifi cant diff erences were also observed in chemical composition of the aerial parts of plants in relation to the number of harvests, with control treatment for the third cutting having the higher content in sugars, organic acids, saturated and monounsaturated fatty acids, and 1st cutting showed the best results for tocopherols. In conclusion, successive harvests (two or three harvests) increased total yield of C. spinosum plants, comparing to control plants, whereas they had a negative eff ect on sugar, organic and fatty acids content.