RESUMO
Phytochemical and antioxidant activity of quinoa flour was evaluated after subjected to gamma irradiation processes at dose 3 and 6 kGy. Both non-irradiated and irradiated quinoa samples were subjected to successive extractions in ethanol solvent. The antioxidant activity after gamma irradiation treatment was investigated via Ferric reducing antioxidant power (FRAP) and radical-scavenging activity (RSA) using 2,2-diphenyl-1-picrylhydrazyl (DPPH).Total phenolic and flavonoid content were analyzed using FolinCiocalteu micro-method, aluminium chloride (AlCl3) method and High Performance Liquid Chromatography (HPLC). As well as, effect of irradiation treatment on saponin was also evaluated. Irradiation treatment showed slight differences in the saponin content after exposure to 3 and 6 kGy. Irradiation process enhanced both total phenolic content (TPC) and Total flavonoid content (TFC), TPC were 34.52 and 30.92 mg Gallic Acid Equivalent (GAE)/100g compared to 26.25 mg GAE/100g in non-irradiated quinoa. TFC were 67.44 and 62.89 mg Quercetin Equivalents (QE)/100g compared to 53.15 mg QE/100g. Irradiation dose 3 kGy significantly (p> 0.05) decreased the IC50 as DPPH-RSA and increased the FRAP.(AU)
Atividades fitoquímica e antioxidante da farinha de quinoa foram analisadas após submissão a processos de irradiação gama nas doses 3 e 6 kGy. As amostras de quinoa não irradiadas e irradiadas foram submetidas a extrações sucessivas em solvente etanol. A atividade antioxidante, após o tratamento com irradiação gama, foi investigada por meio do poder antioxidante redutor férrico (ARF) e da atividade de eliminação de radicais (AER) usando 2,2-difenil-1-picril-hidrazil (DPPH). O conteúdo fenólico total e o teor de flavonoide foram analisados usando o método de Folin-Ciocalteu, método de cloreto de alumínio (AlCl3) e cromatografia líquida de alta eficiência (CLAE). Além disso, o efeito do tratamento de irradiação na saponina também foi avaliado. O tratamento por irradiação não mostrou diferenças significativas no conteúdo de saponina após exposição a 3 e 6 kGy. O processo de irradiação aumentou o conteúdo fenólico total (CFT) e o teor total de flavonoides (TTF); o CFT foi de 34,52 e 30,92 mg de equivalente de ácido gálico (EAG) / 100 g em comparação com 26,25 mg de EAG / 100 g na quinoa não irradiada. Os TTF foram 67,44 e 62,89 mg de equivalentes de quercetina (EQ) / 100 g em comparação com 53,15 mg de EQ / 100 g. A dose de irradiação de 3 kGy diminuiu significativamente (p > 0,05) o IC50 como DPPH-AER e aumentou o ARF.(AU)
Assuntos
Chenopodium quinoa/química , Chenopodium quinoa/efeitos da radiação , Compostos Fitoquímicos/análise , Antioxidantes/análiseRESUMO
BACKGROUND: There is renewed interest in quinoa as a potential source of vegetable oils; however, there is no information about how environmental conditions affect its fatty acid composition, a critical indicator of its oil quality. The fatty acid concentrations of four cultivars adapted to temperate environments were compared at three sowing dates to evaluate the effect of environmental conditions during the seed-filling period on the variation in oil quality. RESULTS: The interaction between cultivar and sowing date was the main source of variation explaining the changes in the lipid content and fatty acid concentrations in quinoa. Most of the variation in the concentration of unsaturated fatty acids was attributed to the temperature and solar radiation during the seed-filling period; cultivar-specific responses to photo-thermal conditions were observed among the sea-level quinoa cultivars evaluated. CONCLUSION: The lipid content and concentration of fatty acids in quinoa are affected by sowing date. This effect is exerted through changes in temperature and solar radiation conditions. This managing practice can therefore be used to achieve quinoa oil with different qualities. © 2019 Society of Chemical Industry.
Assuntos
Chenopodium quinoa/química , Óleos de Plantas/química , Chenopodium quinoa/classificação , Chenopodium quinoa/metabolismo , Chenopodium quinoa/efeitos da radiação , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Luz , Valor Nutritivo , Óleos de Plantas/metabolismo , Sementes/química , Sementes/classificação , Sementes/metabolismo , Sementes/efeitos da radiação , TemperaturaRESUMO
Morphological and physiological responses of seedlings to different solar UV-B irradiances were evaluated in two varieties of quinoa (Chenopodium quinoa Willd.), a crop species from Andean region of South America. Cristalina and Chucapaca varieties were grown at 1965m a.s.l in a glasshouse under natural light conditions for 18 days, and then transferred to outdoors under near-ambient (+UV-B) and strongly reduced (-UV-B) solar UV-B radiation. Exposition to -UV-B increased cotyledon area and seedling height in Cristalina variety whereas leaf number decreased compared to +UV-B. By contrast Chucapaca variety was not affected by UV-B treatments. Seedling fresh weight (FW), root length and leaf thickness did not show significant differences between +UV-B and -UV-B treatments. Mesophyll tissue was slightly affected by solar UV-B reduction. Chlorophyll content was differentially affected by UV-B treatments. Under +UV-B the highest value was observed in Cristalina variety, while in Chucapaca it was observed under -UV-B treatment. Chlorophyll content was slightly higher in leaves than in cotyledons, but there was no difference in the distribution pattern. Chlorophyll a/b ratio and carotenoid content did not show significant differences between UV-B treatments. Leaf UVB-absorbing compounds showed significant differences between UV-B treatments in Chucapaca only, while there were no significant differences in Cristalina variety. UVB-absorbing compounds of cotyledons did not show significant differences between +UV-B and -UV-B treatments. Sucrose, glucose and fructose showed different distribution patterns in cotyledons and leaves of the two varieties under near-ambient and strongly reduced UV-B. Results demonstrated that varieties of quinoa exhibit different morphological and physiological responses to changes in solar UV-B irradiance, but these responses cannot be used to predict the sensitivity to solar UV-B during a short-term exposition. Also, this study can be useful to learn about the plasticity of metabolic pathways involved in plant's tolerance to solar UV-B radiation.
Assuntos
Chenopodium quinoa/crescimento & desenvolvimento , Chenopodium quinoa/efeitos da radiação , Raios Ultravioleta , Chenopodium quinoa/classificação , Clorofila/efeitos da radiação , Cotilédone/química , Cotilédone/efeitos da radiação , Folhas de Planta/química , Folhas de Planta/efeitos da radiaçãoRESUMO
UV-B radiation (280-320 nm) is harmful to living organisms and has detrimental effects on plant growth, development and physiology. In this work we examined some mechanisms involved in plant responses to UV-B radiation. Seedlings of quinoa (Chenopodium quinoa Willd.) were exposed to variable numbers of UV-B radiation doses, and the effect on cotyledons was studied. We analyzed (1) cotyledons anatomy and chloroplasts ultrastructure; (2) peroxidase activity involved in the lignification processes; and (3) content of photosynthetic pigments, phenolic compounds and carbohydrates. Exposure to two UV-B doses induced an increase in the wall thickness of epidermal cells, which was associated with lignin deposition and higher activity of the peroxidase. The chloroplast ultrastructure showed an appearance typical of plants under shade conditions, likely in response to reduced light penetration into the mesophyll cells due to the screening effect of epidermal lignin deposition. Exposure to UV-B radiation also led to (1) enhancement in the level of phenolics, which may serve a protective function; (2) strong increase in the fructose content, a fact that might be related to higher requirement of erythrose-4P as a substrate for the synthesis of lignin and phenolics; and (3) reduction in the chlorophyll concentration, evidencing alteration in the photosynthetic system. We propose that the observed lignin deposition in epidermal tissues of quinoa is a resistance mechanism against UV-B radiation, which allows growing of this species in Andean highlands.