Green extraction of glycosides from Stevia rebaudiana (Bert.) with low solvent consumption: A desirability approach

The sweet flavor of Stevia rebaudiana (Bert.) leaf extract is well known and has raised the interest of huge food companies due to its natural bid. The extraction of their main glycosides stevioside and rebaudioside A is an important step on the preparation of final Stevia granules. The aim of the work reported here was to study and optimize the dynamic maceration of Stevia leaves using water and ethanol as green solvents. For instance, a fractional factorial design was chosen to evaluate the individual effects of the drug powder size, weight ratio of drug to solvent, temperature, agitation, and time on the yield of these glycosides. The glycosides were quantified by high pressure liquid chromatography. An exhaustive extraction by successive maceration steps showed that ethanol 70% was superior to water and ethanol 90% for stevioside and rebaudioside extraction. The liquid extract composition in dry basis and the yield of stevioside and rebaudioside A were significantly affected by the drug to solvent weight ratio, showing that larger volumes of solvent should be used. Furthermore, increasing solvent volume favors the extraction of the stevioside by a twofold factor as compared to rebaudioside A. Among the other factors, only drug powder size affected the yield of rebaudioside A significantly. The optimal solution for S. rebaudiana leaves dynamic extraction estimated by desirability functions methodology led to a condition which allows obtaining extraction yields of 2.31 and 1.24% for stevioside and rebaudioside A and their concentrations in dried extract corresponding to 8.38 and 4.51%, respectively. These high yields were obtained with drug to solvent ratio (1:10, w/w) much higher than previous works, thus resulting in a more sustainable and green process

ESTUDOS DE CARACTERÍSTICAS REPRODUTIVAS DE ANIMAIS DA RAÇA CANCHIM, CRIADOS A PASTO, NO ESTADO DO PARANÁ, BRASIL

Beef production efficiency depends heavely on reproductive performance. Information on age at first calving indicates sexual precocity. Good management of young animal and elimination of factors that negatively interfere with growth and development of heifers contribute to shorten age at first calving. This trait, together with calving interval and conception rate of heifers after their first calving were studied from records of 3.091 Canchim females, born from 1974 through 1998, at Estação Experimental Fazenda Modelo/IAPAR, Ponta Grossa-PR. Data were analyzed using SAS program. Average calving interval, computed using least squares methods, was 16.79 ± 0.43 months, with coefficient of variation equal to 32.07. The R square from the statistical model was 19.84%. For calving interval, only year of birth, month of birth and month of previous calving were significant. When interval between first and second calving was studied, month of previous calving was not significant. Considering that data came from controlled animals, the average calving interval was too long in contrast with the ideal (12 months). Improving management practices should result in shorter calving interval in this herd.A produção eficiente de gado de corte depende muito do seu desempenho reprodutivo. Informações sobre a idade ao primeiro parto evidenciam a precocidade do animal. A boa criação dos animais jovens e a eliminação de fatores que interferem negativamente no crescimento e desenvolvimento das novilhas contribuem para diminuir a idade ao primeiro parto.  Essa característica, juntamente com o intervalo de partos e a taxa de reconcepção de novilhas Canchim foram estimadas analisando-se registros pertencentes ao banco de dados do Instituto Agronômico do Paraná (IAPAR), totalizando 3.091 partos, ocorridos no período de 1974 a 1998. Esses dados foram analisados utilizando o programa SAS, para se processar as respectivas análises estatísticas. A média para o intervalo de partos geral, estimada pelo método dos quadrados mínimos, foi de 16,79 ± 0,43 meses. O modelo estatístico justificou 19,84%, com um coeficiente de variação de 32,07. Das fontes de variação do modelo, apenas mês, ano e mês do parto anterior foram significativos para o intervalo de partos (geral). Quando se estudou essa característica entre o primeiro e segundo parto, o mês do parto anterior não foi significativo, apenas mês e ano de parto o foram. Considerando que os dados são provenientes de animais controlados, constatou-se médias elevadas em relação ao ideal (12 meses). A implementação de melhorias no manejo para esses animais pode reduzir os valores de intervalo entre partos na propriedade

H-dibaryons and Primordial Nucleosynthesis

The apparent discrepancy between abundances of light nuclides predicted by the standard Big-Bang and observational data is explained, by assuming the presence of metastable H dibaryons at the nucleosynthesis era. These dibaryons could be formed out of a small fraction of strange quarks at the moment of the confinement transition. For a primordial deuterium abundance of the order of 3 10^{-5}, the measured differences in the 4He abundances requires a relative abundance of H dibaryons of the order of n_H/n_B = 0.07, decaying in a timescale of the order of 10^5 s.Comment: Latex, 5 pages, to appear in PR

Дискусійні питання історії ЗУНР

У статті аналізуються питання, які все ще залишаються в історіографії Західноукраїнської Народної Республіки. Автор звертає увагу на контроверсійні точки зору щодо революційних подій, які відбулися 1 листопада 1918 р. у Львові, стосовно часу існування ЗУНР, Акту злуки УНР та ЗУНР, причин поразки Української Галицької армії тощо.The author of the article analyses the questions that are still disputable in modern Ukrainian historiography. The author attracts our attention to the controversial points of view concerning the type of revolutionary events which took place on the 1 st of November 1918 in Lviv, concerning the time of WUPR existence, concerning the Act of Unification of Western Ukrainian People’s Republic end Ukrainian People’s Republic , concerning the reasons of the defeat of Ukrainian army, etc

Comparative characterization of resistance proteins in Coffea species

info:eu-repo/semantics/publishedVersio

Adding forests to the water–energy–food nexus

Forest and landscape restoration is a promising strategy for improving water, energy and food securities. We advocate that ‘forest security’ should form a fourth, foundational dimension of a novel water, energy, food and forest security nexus framework. Key principles of this new framework support an integrated role of forests in sustainable development, and engagement of local communities in nature-based solutions, particularly in the Global South. We believe that this new approach can help to accelerate the pace and magnitude of changes needed for achieving the United Nations Sustainable Development Goals. © 2020, Springer Nature Limited