Consumo actual de edulcorantes naturales (beneficios y problemática): Stevia / Current consumption of natural sweeteners (benefits and problems): Stevia

La estevia [Stevia rebaudiana (Bertoni)] es un arbusto de tipo perenne de la familia de las Asteraceas que crece en áreas tropicales y subtropicales de Suramérica. Hoy en día, su cultivo se ha extendido a otras regiones del mundo, incluyendo Canadá y algunas partes de Asia, Europa y México, donde sus hojas se han utilizado tradicionalmente como edulcorante natural durante cientos de años. En la actualidad, el uso potencial y las implicaciones prácticas de la estevia como un edulcorante se muestran en una serie de alimentos procesados, ya que contiene glucósidos de esteviol como ingrediente activo, que puede ser bajo o no calórico, y hasta 100-300 veces más dulce que la sacarosa. Además, las hojas secas de estevia contienen también minerales, vitaminas, compuestos fenólicos, flavonoides y otros compuestos antioxidantes, con propiedades antimicrobianas y antioxidantes. Stevia acumula hasta un 30 % de los glucósidos de esteviol (SGs por su sigla en inglés) del peso seco de las hojas. El esteviósido y el rebaudiósido A son las principales SGs. Desde diciembre de 2011, los SGs (E 960) se han autorizado como aditivo alimentario y edulcorante en Estados Unidos. Su uso en diversas categorías de alimentos está regulado como por ejemplo en suplementos alimenticios y alimentos dietéticos para propósitos médicos especiales y control de peso. Sin embargo, la información ofrecida al consumidor es engañosa y dista de ser confiable. Este artículo ofrece al público interesado, datos que deben de ser evaluados al comprar productos adicionados con estevia (AU).

Stevia [Stevia rebaudiana (Bertoni)] is a perennial shrub belonging to the Asteraceae family that grows in tropical and subtropical areas of South America. Today its cultivation has spread to other regions of the world, including Canada and some parts of Asia, Europe and México, where its leaves have been used traditionally as a natural sweetener for hundreds of years. Nowadays, the potential use and practical implications of Stevia as a sweetener are shown in a number of processed foods, because it contains steviol-glycosides, which are low- or non-caloric ingredients, up to 100­300 times sweeter than sucrose. In addition, dry Stevia leaves also contain minerals, vitamins, phenolic compounds, flavonoids and other antioxidant compounds, with antimicrobial and antioxidant properties. Stevia accumulates up to 30% of diterpenoid steviol glycosides (SGs) of the leaf dry weight. Stevioside and rebaudioside A are the major SGs. Since December 2011, SGs (E 960) have been permitted for use as food additive and a sweetener in the United States. Its use in various food categories is regulated, e.g. food supplements and dietary foods for special medical purposes and weight control. However, the information offered to the consumers is misleading and far from reliable. This article offers the interested public, data that should be evaluated when buying products added with Stevia (AU).

Diterpenes and a new benzaldehyde from the mangrove plant Rhizophora mangle

ABSTRACT This work describes the isolation, by high-speed counter-current chromatography, of the diterpenes manool, jhanol and steviol and the benzaldehyde p-oxy-2-ethylhexyl benzaldehyde from the stilt roots hexane extract of the mangrove plant Rhizophora mangle L., Rhizophoraceae. For this, a non-aqueous biphasic solvent system composed of hexane–acetonitrile–methanol 1:1:0.5 (v/v/v) was applied. As far as we know, only steviol was previously isolated in Rhizophoraceae and this is the first time that p-oxy-2-ethylhexyl benzaldehyde is reported.

Dry biomass and glycosides yield from Stevia rebaudiana leaves under different harvesting times / Produtividade de biomassa seca e glicosídeos em Stevia rebaudiana cultivada em diferentes períodos da estação de crescimento

The Stevia rebaudiana (Bert) Bertoni is a perennial plant native in the Amambay Hills in the South America. The leaves of this plant produce various natural sweeteners useful to replace the human needs of saccharine. The aims of this study were to evaluate the dry biomass and the glycoside concentration in the Stevia leaves along different growing periods of the growing season to determine the best time to harvest the crops. We selected and identified six groups of 20 plants for analyses. The highest plant yield was found in December, from the first harvest for the groups 3, 4 and 2 with 292.4; 285.2 and 206.7 g m-2, respectively. The sweetener concentrations and the glycosides ranged within the harvests and the compounds analyzed. The highest concentrations of stevioside (12.16% - group 1 and 11.36% - group 5) and rebaudioside C (2.43% - group 5 and 1.95% - group 1) were found in January while rebaudioside A had the highest concentrations of 7.01% (group 6); 6.16% (group 4) and 6.15% (group 3) in December, February and March, respectively. The environmental conditions have influence in days to harvesting as well as in the concentration of glycosides.

Originária na serra de Amanbaí, Paraguai, América do Sul, a Stevia rebaudiana é uma planta perene que possui em suas folhas edulcorantes naturais com alto poder adoçante e que podem substituir a sacarose. Objetivou-se com esse experimento avaliar a biomassa seca e a concentração de glicosídeos em folhas de S. rebaudiana em diferentes períodos do ano para determinar a melhor época para a colheita. Seis grupos com 20 plantas foram selecionados e identificados perfazendo um total de 120 plantas. As maiores produtividades de biomassa seca foram alcançadas no mês de dezembro quando ocorreu o primeiro corte nos grupos 3 com 292,4, 4 com 285,2 e 2 com 206,7 g m-2 . A concentração dos glicosídeos variou entre os períodos de crescimento de cada corte e entre os compostos analisados. As concentrações mais altas de esteviosídeo (12,16% - grupo 1 e 11,36% - grupo 5) e rebaudiosídeo C (2,43% - grupo 5 e 1,95% - grupo 1) foram observadas nas colheitas realizadas em janeiro, enquanto que para o rebaudiosídeo A (7,01% - grupo 6; 6,16% - grupo 4 e 6,15% - grupo 3), as maiores porcentagens foram alcançadas nos meses de dezembro, fevereiro e março.

Perspectives on Low Calorie Intense Sweeteners with a Focus on Aspartame and Stevia.

The safety of some food additives/E-numbers, including low calorie (intense) sweeteners (LCS), is constantly the subject of dispute and controversy. However, since LCS have been assigned an acceptable daily intake (ADI) and an E-number following extensive assessment of available safety and toxicological data, consumer safety is assured. These substances have been carefully evaluated, for example by the European Food Safety Authority (EFSA), leading to the conclusion that they are essentially safe when consumption is below ADI levels. Although, intake data indicate that general consumption of LCS is relatively low, many people appear to remain concerned about their safety, particularly aspartame (E951). More recently, stevia (steviol glycosides, E960) has been marketed as a “natural” alternative to aspartame. However, it is unclear whether stevia can live up to its promises. With regards to public health, the real risk within our diet is not the safety of food additives, but rather more likely to be the potential impacts of consuming too much energy and/or an unhealthy dietary pattern.

Risk Assessments of Cyclamate, Saccharin, Neohesperidine DC, Steviol Glycosides and Neotamefrom Soft Drinks, “Saft” and Nectar.

The Norwegian Scientific Committee for Food Safety (Vitenskapskomiteen for mattrygghet, VKM), Panel on Food Additives, Flavourings, Processing Aids, Materials in Contact with Food and Cosmetics, has at the request of the Norwegian Food Safety Authority (Mattilsynet) conducted a risk assessment of the intense sweeteners cyclamate, saccharin, neohesperidine DC, steviol glycosides and neotame in soft drinks, “saft” and nectar. The risk assessment includes exposure assessments and the calculated exposures are compared to the acceptable daily intake (ADI) for the respective sweeteners. VKM was also requested to compare the current calculated intake of saccharin and cyclamate to the calculated intake reported by VKM in 2007 (the VKM report «Impact on health when sugar is replaced with intense sweeteners in soft drinks, “saft” and nectar») when possible (VKM, 2007). Six different intake scenarios with varying concentrations of added sweeteners (either the average concentration or the highest reported concentration for the respective sweetener) and varying consumption of beverages with sweeteners (either the actual reported consumption of beverages added sweetener or the assumption that all reported beverages were added sweeteners) were used for the exposure calculations. • Scenario 1 gives the best estimate of the current situation in the population (average content of sweeteners, actual reported consumption). • Scenario 2 is based on the average content of sweeteners and that all consumed beverages contain sweeteners. • Scenario 3 is based on the highest reported content of sweeteners and the actual reported consumption. • Scenario 4 is based on the highest reported content of sweeteners and that all consumed beverages contain sweeteners. Scenarios 5 and 6 are based on the maximum allowed amounts of sweeteners within a category in accordance with the Regulation on food additives, within the categories soft drinks, “saft” and nectar in Norway (Regulation No 668 of 6 June 2011 on food additives, 2011). • In scenario 5 the consumption of beverages with added sweeteners or sugar reported in dietary surveys were used for the calculations. • In scenario 6 it was assumed that all consumed soft drinks, “saft” and nectar contained sweeteners (no sugar). In the current risk assessment, the intake of the sweeteners was calculated for 2-year-old children and 18-70 year old men and women. Due to lack of new dietary surveys, the other age groups of children and adolescents were not included. For all age groups in all scenarios, the intake of the sweeteners cyclamate, saccharin, neohesperidine DC, steviol glycosides and neotame was below their respective established ADI values. Due to possible differences in the calculation, it was not possible to compare the current calculated intake of saccharin and cyclamate to the calculated intake reported by VKM in 2007. VKM concludes that there is no major health concern related to the intake of the sweeteners cyclamate, saccharin, neohesperidine DC, steviol glycosides and neotame from the beverage categories included in this risk assessment per today. VKM further concludes that among young women who are high consumers of beverages with cyclamate, and 2-year-old children who are high consumers of beverages with steviol glycosides, the estimated intake approaches the ADI values. The high intakes approaching ADI are considered conservative estimates, as the highest reported content of sweetener or the maximum allowed amounts is used. Thus, these estimates are only relevant for the part of the population that are both loyal to beverages with sweeteners and a particular brand of sweetened beverage. It should be noted that intake of sweeteners from other foods or from tabletop sweeteners is not included in the intake estimates, and that a considerable contribution from these sources cannot be excluded.

Steviol effect, a glycoside of Stevia rebaudiana, on glucose clearances in rats / O efeito do esteviol, um glicosídeo da Stevia rebaudiana, no clearance da glicose em ratos

Stevia rebaudiana, a South American plant normally used as a natural herbal sweetener, has been suggested as exerting beneficial effects on human health, including as an antihypertensive and antihyperglycemic. The present experiment was undertaken to evaluate the renal excretion of steviol, the aglycone of several natural products extracted from the leaves of S. rebaudiana, and to clarify the actual participation of this compound on the renal excretion of glucose in rats, which has been previously suggested as the preferential action of steviol on the Na+-glucose renal tubular transport system. Steviol was obtained by enzymatic hydrolysis of stevioside with pectinase. Thirty normal male Wistar rats weighing 345 g were used. After a control period, steviol was infused iv at three doses (0.5, 1.0 and 3.0 mg.kg-1/h), according to classical clearance techniques. During all the experiments no significant changes in inulin clearance (Cin) and p-aminohipuric acid clearance (C PAH) were observed. Administration of steviol resulted in a statistically significant increase in the fractional sodium excretion (FeNa+), fractional potassium excretion (FeK+), urinary flow as percent of glomerular filtration rate (V/GFR) and glucose clearance (C G) when compared to controls, but these effects were absent with the dose of 0.5 mg.kg-1/h. The steviol clearance (C S) was higher than the Cin and lower than the C PAH at all the doses employed in this study. The data suggest that steviol is secreted by renal tubular epithelium, causing diuresis, natriuresis, kaliuresis and a fall in renal tubular reabsorption of glucose.

Stevia rebaudiana, uma planta da América do Sul usada como adoçante natural, parece exercer efeitos benéficos para a saúde humana, incluindo ação anti-hipertensiva e anti-hiperglicêmica. No presente trabalho objetivamos avaliar a excreção renal do esteviol, uma aglicona extraída das folhas de S. rebaudiana, e elucidar a participação deste composto na excreção renal de glicose em ratos, o qual foi sugerido agir no sistema de transporte tubular renal Na+-glicose. O esteviol foi obtido por hidrólise enzimática com pectinase. Foram usados 30 ratos Wistar machos e pesando 345 g. Após um período controle, o esteviol foi infundido iv em três doses (0,5, 1,0 e 3,0 mg.kg-1/h) de acordo com técnicas clássicas de clearance. Durante os experimentos não houve alterações significantes no clearance da inulina (Cin) e do ácido-aminohipúrico (C PAH). A administração de esteviol resultou em um aumento estatisticamente significante na excreção fracional de sódio (FeNa+) e potássio (FeK+ ), no fluxo urinário como porcentagem da taxa de filtração glomerular (V/GFR) e do clearance de glicose (C G) quando comparados aos animais controles, embora estes efeitos estivessem ausentes na dose de 0,5 mg.kg-1/h. O clearance de esteviol (C S) foi maior que o Cin e menor que o C PAH em todas as doses usadas nos experimentos. Os dados sugerem a secreção de esteviol pelo epitélio tubular renal, causando diurese, natriurese, caliurese e uma redução na reabsorção tubular renal de excreção de glicose.