Qualitative and Quantitative Analysis of Phylloplane Mycoflora of Stevia Rebaudiana Bertoni

The aim of the present investigation is to study the fungal flora of young and matureleaves of S. rebaudiana. Young and mature leaves of S. rebaudiana were used for isolation offungi. Phylloplane mycoflora were isolated from leaves of S. rebaudiana by using threemethods i.e. dilution plate method, leaf impression method and leaf washing method. Dilutionplate method and leaf washing method were applied for quantitative analysis and leafimpression method for qualitative analysis. A total of 35 fungal species comprisingZygomycetes, Ascomycetes and Deuteromycetes including sterile forms were isolated duringthe course of investigation. A total of thirteen fungal species viz. Aspergillus niger, A. flavus, A.fumigatus, Penicillium cyclopium, P. chrysogenum, Cladosporium elatum, C. cladosporioides,Mucor etc. were isolated from mature leaves. Eleven fungal species were found by leafimpression method, eight by leaf washing method and six by dilution plate method.Aspergillus, Penicillium and Cladosporium species were found to be dominant among all thespecies. Phylloplane fungal population on mature leaves of S. rebaudiana was 1.68×102 /cm2leaf area. Thus, the outcome of study presents a clear picture about fungal population anddiversity in phylloplane of S. rebaudiana mature leaves.

Efectos de la ingesta de los edulcorantes estevia y D-tagatosa sobre el metabolismo de la glucosa, ácido úrico y apetito-saciedad / Effects of stevia and D-tagatose sweeteners intake om glucose, uric acid metabolism and appetite-satiety

INTRODUCCIÓN: Si bien, los edulcorantes no nutritivos (ENN) estevia y D-tagatosa han sido reportados como seguros, han demostrado tener algunos efectos metabólicos tras su ingesta. OBJETIVO: Describir los efectos de la ingesta de estevia y D-tagatosa sobre el metabolismo de la glucosa y ácido úrico, y del apetito-saciedad, a partir de la evidencia disponible. MÉTODOS: Revisión descriptiva. Se realizó búsqueda en PubMed utilizando los siguientes términos y palabras clave: "stevia rebaudiana", "tagatose", "D-tagatose", "blood glucose", "insulin", "metabolic processes", "uric acid", "hyperuricemia", "appetite" o "satiety". El análisis de los estudios seleccionados fue discrecional. RESULTADOS: Existen estudios que demuestran efectos beneficiosos tras el consumo de estevia o D-tagatosa sobre el control glicémico, apetito y saciedad tanto en sujetos sanos como con alteraciones en el metabolismo de la glucosa. Por otra parte, un número importante de estudios que evalúan la ingesta de estevia reportan efectos nulos sobre dichos parámetros. En relación al ácido úrico, solo un estudio en sujetos con enfermedad renal crónica reporta aumento en la concentración de ácido úrico plasmático tras la ingesta de 500 mg/día de estevia. Pocos estudios han evaluado el efecto de la ingesta de D-tagatosa sobre uricemia, en sujetos sanos y diabéticos, reportando un aumento transitorio y significativo en los niveles de ácido úrico sérico, sin embargo, no se ha logrado demostrar un efecto hiperuricémico asociado. Es importante destacar que la metodología de los estudios revisados es heterogénea, especialmente en relación al tamaño muestral, tiempo, dosis y vía de adminitración del edulcorante. CONCLUSIÓN: La ingesta de estevia y D-tagatosa ha demostrado efectos beneficiosos sobre el metabolismo de la glucosa, el apetito y la saciedad. El efecto del consumo de D-tagatosa sobre ácido úrico sérico requiere mayor evidencia para demostrar su significancia clínica.

INTRODUCTION: No-nutritive sweeteners stevia and D-tagatose have been reported as safe according to their acceptable daily intake, however, they have been shown to have metabolic effects after their ingestion. OBJECTIVE: To describe the effects of stevia and D-tagatose intake on parameters associated to glucose, uric acid metabolism and on appetite-satiety, considering the available evidence. METHODS: Descriptive review. PubMed search was carried out to identify the totality of the published articles. The following terms and key words were used: "stevia rebaudiana", "tagatose", "D-tagatose", "blood glucose", "insulin", "metabolic processes", "uric acid", "hyperuricemia", "appetite" o "satiety". The analysis of the selected studies was discretionary. RESULTS: studies have shown beneficial effects of stevia and D-tagatose consumption on glycemic control, appetite and satiety in healthy subjects as well as subjects with impairment glucose metabolism. On the other hand, a significant number of studies evaluating estevia intake report null effects on these parameters. In relation to uric acid, only one study in subjects with chronic kidney disease reported an increase in plasmatic uric acid concentration after the intake of 500 mg/day of stevia. Several studies have evaluated the effect of D-tagatose intake on plasmatic uric acid, in healthy and diabetic subjects, reporting a transient and significant increase in serum uric acid levels, however, has not been able to demonstrate an associated hyperuricemic effect. It is important to highlight that the methodology of the studies reviewed is heterogeneous, especially in relation to sample size, dose administered, time and route of exposure to the sweetener. CONCLUSION: Stevia and D-tagatose intake has shown beneficial effects on glucose metabolism, appetite and satiety. The effects of the consumption of both sweeteners on uric acid require further study to demonstrate their clinic significance.

Morpho-anatomical study of Stevia rebaudiana roots grown in vitro and in vivo

ABSTRACT Stevia rebaudiana (Bertoni) Bertoni, Asteraceae, is used as a food additive because its leaves are a source of steviol glycosides. There are examples of tissue culture based on micropropagation and phytochemical production of S. rebaudiana leaves but there are few studies on adventitious root culture of S. rebaudiana. More than 90% of the plants used in industry are harvested indiscriminately. In order to overcome this situation, the development of methodologies that employ biotechnology, such as root culture, provides suitable alternatives for the sustainable use of plants. The aim of this study was to compare morpho-anatomical transverse sections of S. rebaudiana roots grown in vitro and in vivo. The in vitro system used to maintain root cultures consisted of a gyratory shaker under dark and light conditions and a roller bottle system. Transverse sections of S. rebaudiana roots grown in vitro were structurally and morphologically different when compared to the control plant; roots artificially maintained in culture media can have their development affected by the degree of media aeration, sugar concentration, and light. GC–MS and TLC confirmed that S. rebaudiana roots grown in vitro have the ability to produce metabolites, which can be similar to those produced by wild plants.

Efeitos de dois adoçantes naturais: Stevia Rebaudiana Bertoni e Sorbitol no metabolismo bacteriano para o crescimento e produção de ácidos / Effects of two natural sweeteners Stevia Rebaudiana Bertoni and Sorbitol on the growth and acid production of the bacteria

O objetivo da pesquisa foi comparar os efeitos de edulcorantes naturais utilizados como substrato por Streptococcus mutans e Lactobacillus acidophilus, verificando a capacidade desses microrganismos em metabolizar os edulcorantes, favorecendo o crescimento e a produção de ácidos. Para tal estudo, realizou-se um total de 180 leituras para as variáveis crescimento e produção de ácido, e para o processamento dos dados usou-se o pacote estatístico SPSS. Dadas às condições da metodologia, foi possível concluir que a Stevia Rebaudiana Bertoni ofereceu melhores resultados na redução do crescimento bacteriano e na produção de ácidos do que o Sorbitol.

This paper aimed at comparing the effects of natural sweeteners used as a substrate for Streptococcus mutans and Lactobacillus acidophilus, in order to verify the ability of these microorganisms to metabolize sweeteners, promoting the growth and the production of acids. For this study, the variables "growth" and "acid production" were analyzed and the processing data was based on the SPSS statistical package. It was concluded that Stevia rebaudiana Bertoni offered better results in reducing bacterial growth and production of the Sorbitol acids.

Quality Characteristics of Rice Cookies Prepared with Stevia rebaudiana Leaf

The purpose of this study was to determine the optimal recipe of rice cookies with two different amounts of Stevia rebaudiana leaf and grape seed oil, using a central composite design (CCD). In addition, mixing conditions of rice cookies were optimized by sensory evaluation and mechanical and physicochemical analysis using response surface methodology (RSM). RSM was used to obtain 10 experimental points (including two replicates of Stevia rebaudiana leaf and Grape seed oil), and the formulation of Stevia rebaudiana leaf added rice cookies was optimized using rheology. The results of mechanical and physicochemical analysis showed significant values for lightness, redness, yellowness, hardness, spread factor, loss rate, leavening rate, sweetness, moisture, pH, and density (P<0.001), results of the sensory evaluation showed significant values for color, flavor, taste, texture, appearance, and overall quality (P<0.05). As a results, optimal sensory ratio was found to be 1.98 g of Stevia rebaudiana leaf and 37.94 g of Grape seed oil.

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.

Replacing sugar with S. rebaudiana extracts on the physicochemical and sensory properties of strawberry ice cream / Substituição do açúcar com extratos de S. rebaudiana sobre as propriedades físico-químicas e sensoriais de sorvete de morango

ABSTRACT: Ice cream is a product whose formulation requires considerable amounts of sugar. In addition to providing flavor, sugar contributes to the physicochemical characteristics of ice cream but its consumption in large quantities is related to chronic diseases such as diabetes and obesity. For this reason, the food industry seeks to formulate products with sweeteners that preserve the physicochemical and sensory characteristics of the original product. Stevia rebaudiana is a plant that naturally contains glycosides with no calories and high sweetening capacity and it is considered safe for consumption. Therefore the aim of this research was to evaluate the effect of replacing sugar with different levels of extracts of S. rebaudiana Morita II and Criolla, on the physicochemical and sensory properties of strawberry ice cream. Using a 2x2 factorial experimental design, a total of 4 formulations were prepared with two levels of concentration of the aqueous extract of Stevia rebaudiana (5 or 8%) and the variety of S. rebaudiana (Morita II or Criolla). Proximate composition, physicochemical properties and sensory evaluation were determined in processed products. The proximate analysis of strawberry ice cream varied significantly (P<0.05) depending of variety and level used on the formulation. The viscosities of all ice cream mixes were decreasing as the shear rate was increased, indicating a pseudoplastic behavior. The sensory analysis showed differences (P<0.05) among the formulations tested, however the score of all products were above the indifference point, suggesting that all of these formulations may have a commercial potential.

RESUMO: Sorvete é um produto cuja formulação requer quantidades consideráveis de açúcar. Além de proporcionar o sabor, o açúcar contribui para as propriedades físico-químicas do sorvete, mas o seu consumo em grandes quantidades está relacionada com as doenças crônicas, como diabetes e obesidade. Por essa razão, a indústria alimentícia buscou formular produtos com adoçantes para manter as propriedades físico-químicas e sensoriais do produto original. Stevia rebaudiana é uma planta que contém naturalmente glicosídeos sem calorias com alta capacidade adoçante, cujo consumo é considerado seguro. Portanto, o objetivo deste estudo foi avaliar o efeito da substituição do açúcar por diferentes níveis de extratos de S. rebaudiana Morita II e Criolla, sobre as propriedades físico-químicas e sensoriais do sorvete de morango. Usando um modelo experimental de fator 2x2, um total de 4 formulações foram preparadas com 2 níveis de concentração de extrato aquoso de Stevia rebaudiana (5 ou 8%) e a variedade de Stevia (Morita II ou Criolla). Os produtos processados foram submetidos a análises proximais e físico-químicas, e avaliação sensorial foi realizada para três deles. A análise do sorvete de morango teve uma variação estatisticamente significativa (P<0,05), dependendo da variedade e do nível utilizado na formulação. A viscosidade da mistura de sorvete diminuía com o aumento da velocidade de corte, indicando um comportamento pseudoplástico. A análise sensorial mostrou que não houve diferenças significativas (P>0,05) entre as formulações avaliadas e a pontuação de todos os produtos estava acima do ponto de indiferença, indicando que todos eles podem ter um potencial comercial.

Stevia rebaudiana loaded titanium oxide nanomaterials as an antidiabetic agent in rats

Abstract Stevia rebaudiana (Bertoni) Bertoni, Asteraceae, is a plant with hypoglycemic and antihyperlipidemic properties. S. rebaudiana (SrB) has become a lead candidate for the treatment of the diabetes mellitus. However, chronic administrations of S. rebaudiana are required to cause the normoglycemic effect. Importantly, nanomaterials in general and titanium dioxide (TiO2) in particular have become effective tools for drug delivery. In this work, we obtained TiO2 nanomaterials with SrB at different concentrations (10, 20 and 30 µM) by sol–gel method. After this nanomaterials were characterized by Fourier transform infrared spectroscopy and transmission electron microscopy. Where it was demonstrated, the presence of the S. rebaudiana in TiO2 nanomaterials, which were observed as hemispherical agglomerated particles of different sizes. The nanomaterials were evaluated in male rats whose diabetes mellitus-phenotype was induced by alloxan (200 mg/kg, i.p.). The co-administration of TiO2-SrB (20 and 30 µM) induced a significant and permanent decrease in the glucose concentration since 4 h, until 30 days post-administration. Likewise, the concentrations of insulin, glycosylated hemoglobin, cholesterol, and triacylglycerides showed a significant recovery to basal levels. The major finding of the study was that the TiO2-SrB (20 and 30 µM) has a potent and prolonged activity antidiabetic. TiO2 can be considered like an appropriated vehicle in the continuous freeing of active substances to treat of diabetes mellitus.

Somatic Embryogenesis and Plantlet Regeneration from Protoplast Culture of Stevia rebaudiana.

In order to develop a high-efficiency and reproducible regeneration protocol for Stevia protoplasts, various factors such as type and concentration of enzymes, osmoticum, incubation time, plant material type and age were studied. Protoplasts were successfully isolated from leaves of fourweek- old in vitro grown plants using an enzyme mixture comprising of 2% (w/v) Cellulase Onozuka R-10, 1.5% (w/v) Macerozyme Onozuka R-10, 0.2% (w/v) Driselase and 0.1%(w/v) Pectolyase Y- 23 in 0.5 M mannitol, 2.5 mM CaCl2.2H2O and 5 mM 2 (N-morpholino)-ethanesulfonic acid (MES ) at pH of 5.8. Approximately 8.4±0.40x106 protoplasts g-1fresh weight with 98.8±1.39% viability was obtained after incubating in enzyme solution for 4 hours in dark. Viable protoplasts were collected by centrifugation in the presence of 16% sucrose solution. Protoplasts at density of 5x105 mL-1were cultured on modified KM8P medium supplemented with 0.2 mg L-1 2,4-dicholorophenoxyacetic acid (2,4-D), 1 mg L-1 α-naphthalene acetic acid (NAA), 0.5 mg L-1 zeatin, 0.15 M sucrose and 0.3 M mannitol by agarose-bead or thin layer liquid culture technique. The protoplasts regenerated cell walls within 24 hours. First cell division was observed after culturing for 2-3 days and microcolonies were formed within 4 weeks. Gradually adding fresh medium of lower osmotic pressure into the medium for protoplast culture favored cell division. Compared to liquid culture, agarose bead culture improved division frequency almost 1.5 times effectively and showing a plating efficiency of 13% and 9.1% respectively with survival rate of 23.5% to 14.8%. Upon transfer to Murashige and Skoog’s medium (MS) with 1 mg L-1BA, alone or in combination with NAA or 2, 4-D at 0.1 mg L-1, protoplast-derived calli produced complete plantlets through somatic embryogenesis in 8-weeks. The regenerated plants survived in soil and all were normal with respect to morphology and growth characters. This protocol might lead to the improvement of the Stevia through somatic hybridization, somaclonal variation and genetic engineering by using protoplast based regeneration System.

Chloroplast ultra structure, photosynthesis and enzyme activities in regenerated plants of Stevia rebaudiana (Bert.) Bertoni as influenced by copper sulphate in the medium.

Stevia rebaudiana (Bert.) Bertoni is an important medicinal plant used as noncaloric commercial sweetener. Plants regenerated with higher levels of copper sulphate in the medium exhibited enhanced activity of peroxidase and polyphenoloxidase (PPO) enzymes. Transmission electron microscopy (TEM) revealed increase in size and number of electron dense inclusions in the chloroplasts of plants regenerated at optimised level of copper sulphate (0.5µM) in the medium. There was decrease in chlorogenic acid (CGA) content. Chl-a-fluorescence transient pattern (OJIP) showed that the photosynthesis process was more efficient at 0.5µM CuSO4 in the medium. 

In-Vitro Micropropagation and Media Optimization of Stevia Reboudiana an Important Bio-Sweetener and Medicinal Plant”.

The technique of Plant Biotechnology has an important role to play in the production of agriculture, horticulture and ornamental plants and in the manipulation of plants for improved agronomic performance. In the present study initiation of callus has been done by using explants from auxiliary and apical meristems of Stevia rebaudiana. Explants were inoculated on MS basal medium having Vitamin supplement with Auxin like 2-4, D and NAA (0.5mg/lt. -2.0mg/lt.) alone or in combination with cytokinis like BAP & Kinetin (0.52 mg/lt. -1.0 mg/lt.). Sucrose 30 gm. and agar 4.5 gm./lt. After the formation of explants, they were transferred into shoot induction medium containing different concentration of cytokine like BAP & Kinetin (0.5 mg/lt. to 30 mg/lt.) with additional vitamins. After few days numbers of multiple shoots were formed. Strong and elongated shoots were treated with root initiating medium i.e MS containing Auxin like IBA, NAA & activated charcoal. Maximum 60-70% callusing in 10 to 15 days was initiated on 2-4D (1-2mg/lt.) and 40-50% callusing were reported in medium containing (1.0 NAA & 0.5 mg/lt. BAP) in 25-30 days. Nodular compact cells were formed in 2-4D. The medium containing BAP alone showed shoot formation 70-80% with 40% coconut water. Second rooting medium used was containing NAA and activated charcoal and 85% rooting were observed within 7-10 days after transferring. Finally the cultured plants were transferred for hardening.

In vitro mutation induced by ethylmethane sulfonate in Stevia rebaudiana and SRAP identification of salt-tolerant mutants / 中草药

Objective: The in vitro mutation system of Stevia rebaudiana induced by ethylmethane sulfonate (EMS) was established, and the salt-tolerant mutants were identified by SRAP. Methods: S. rebaudiana plantlets were inoculated on MS media containing NaCl with different concentration to screen the salt-tolerant critical concentration. Plantlets were treated with EMS at different concentration and for different time periods, and EMS mutagenized stems were inoculated on MS medium containing critical NaCl concentration to screen the tolerant variants by SRAP markers. Results: The critical salt concentration of S. rebaudiana plantlets was 1.0%, and the suitable concentration and time of EMS were 0.8%-1.0% and 8-10 h. Among the screened 41 S. rebaudiana tolerant mutants by SRAP molecular markers, four were mutated at DNA level, and the mutation rate was 9.76%. Conclusion: The in vitro mutagenesis system of S. rebaudiana with EMS has been established, which provides a new breeding way for high-yield salt-tolerant S. rebaudiana.

Quality Characteristics of Soybean Milk Added with Stevia Leaf Powder

This study was carried out to evaluate the effects of stevia (Stevia rebaudiana Bertoni) leaf powder on soybean milk quality. Soybean milk was prepared with the addition of 0.1 g (SP1), 0.2 g (SP2), 0.3 g (SP3), 0.4 g (SP4) of stevia leaf powder. The pH of soybean milk added with stevia leaf powders ranged from 7.90 to 7.98, whereas that of control was 7.88. The viscosity of soybean milk added with stevia leaf powder was 11.13~12.71 cp while that of control was 11.09 cp. Soymilk added with stevia leaf powder yielded values of Hunter L (59.40~64.94), a (-7.63~-6.45), and b (18.71~19.63), whereas that of control were 67.45, -4.74 and 20.13, respectively. There was decrease upon addition of stevia leaf powder. During storage, the pH, viscosity, L, and b values were decreased continuously. According to sensory evaluation, taste, and flavor of SP3 were better than the other groups. Quality characteristics between control and SP3 showed no significant differences. Therefore, this study showed the possibility of substituting 0.3 g of stevia leaf powder instead of sugar for creating a standard quality soybean milk with low calories. Upon the results of this study, it may be assumed that there are consequences positive responses to health-oriented consumers when using stevia leaf powder.

Wound healing potential of aqueous crude extract of Stevia rebaudiana in mice

The present study was carried out to evaluate the wound healing potential of crude aqueous extract of Stevia rebaudiana (Bertoni) Bertoni, Asteraceae, in experimental animals. All experiments were conducted following standard procedures. The crude extract was administered topically in graded doses of 150, 250 and 500 mg/kg b.w. was used for evaluating the wound healing potential in excision wound model for fourteen days and orally in the incision wound model for ten days, respectively. Povidone iodine ointment was used as standard (5.0% w/w). Dose dependent activities resulted in both the wound models when compared to the standard (povidone iodine) and the control. Topical application of crude aqueous extract of S. rebaudiana (500 mg/kg b.w) in excision wound model decreased significantly the wound area by 15th day, i.e. 48.2±2.0 compared with control 94.1±1.2. Epithelization time was decreased from 17.3±0.21 to 12.0±0.10 and hydroxylproline content was increased from 32.2±0.11 to 67.6±0.10 when compared with control. In incision wound model breaking strength of wounds, wet and dry granulation of the tissue weight and hydroxyproline were increased significantly from control with AESR. In conclusion, AESR leaves accelerated wound healing activity in mice and thus supports its traditional use.

Spectral Analysis and Chemical Studies of the Sweet Constituent, Rebaudioside A.

Aim: To study NMR spectral analysis and hydrolysis products of Rebaudioside A (1) that has been isolated from Stevia rebaudiana. Study Design: Acquiring NMR and high resolution mass spectral (HRMS) data of Rebaudioside A for structural characterization, and identification of hydrolysis products. Place of Study: Organic Chemistry Department of The Coca-Cola Company, Atlanta, GA 30313, USA. Methodology: The 1D (1H & 13C) and 2D (COSY, HSQC, and HMBC) NMR spectral data of was acquired using Varian Unity Plus 600 MHz instrument using standard pulse sequences. Hydrolysis studies were performed on Rebaudioside A using acid, base and enzymatic studies to identify partial degradation products, aglycone and sugar residues. Results: The proton and carbon values of Rebaudioside A were assigned based on NMR and HRMS data as well as chemical studies. The aglycone was identified as steviol on the basis of enzymatic hydrolysis, sugar was identified as D-glucose from acid hydrolysis and the partial hydrolyzed product was identified as Rebaudioside B from alkaline hydrolysis.

Influencia de la materia orgánica y Azotobacter nigricans en un cultivo de Stevia rebaudiana B / Influência da matéria orgânica e Azotobacter nigricans em uma cultura de Stevia rebaudiana B / Influence of organic matter and Azotobacter nigricans on a Stevia rebaudiana B. plantation

Stevia rebaudiana es una planta que acumula un compuesto edulcorante no calórico conocido como esteviosido. Su cultivo tradicionalmente se fertiliza con compuestos químicos que causan daño al ecosistema, obligando a buscar alternativas orgánicas para mitigar este daño. Objetivo. Evaluar el efecto de la materia orgánica y un biofertilizante con base en Azotobacter nigricans en un cultivo de Stevia rebaudiana ubicado en el departamento de Meta, Colombia. Materiales y métodos. Se establecieron cinco tratamientos: T1 y T2 Incorporando al cultivo compost de residuos domiciliarios en concentraciones de 15 y 30 ton ha-1 respectivamente; T3 y T4 con las mismas concentraciones de compost e inoculando el biofertilizante y T5 solamente con el biofertilizante. El control correspondió a las condiciones normales de cultivo con compost Bokashi. El crecimiento vegetal se evaluó por determinación de biomasa en peso seco, producción y área foliar. El análisis fisicoquímico de suelo incluyó: porcentaje carbono orgánico, humedad y pH. Resultados. La inoculación del biofertilizante produjo un incremento en la velocidad de mineralización del compost, con %CO final de 4,85 entre los 90 y 180 días. Se presentaron diferencias estadísticamente significativas (p< 0,05) entre la producción de biomasa de T2 (1538 kg ha-1) y el control (477 kg ha-1). Respecto al contenido de sólidos solubles T1, T3 y T4 presentaron los más altos valores de °Brix (12,4: 12,35 y 12,15). Conclusiones. La concentración 30 ton ha-1 presentó los mejores rendimientos de biomasa y la aplicación del biofertilizante mostró una correlación positiva con la mineralización del compost y síntesis de glucósidos...

Influence of organic matter and Azotobacter nigricans on a Stevia rebaudiana B. plantation Stevia rebaudiana is a plant that accumulates a non-caloric sweetener compound known as stevioside. This crop is traditionally fertilized with chemicals that are harmful for the ecosystem, forcing to find organic alternatives to mitigate this damage. Objective. To study the effect of organic matter and an Azotobacter nigricans-based bio-fertilizer on a Stevia rebaudiana plantation grown in acidic soil in the Department of Meta, Colombia. Materials and methods. Five treatments were established: T1 and T2 with the application of home organic waste compost at concentrations of 15 and 30 ton ha-1. T3 and T4 with the same compost concentrations and inoculating the A. nigricans bio-fertilizer. T5 contained the bio-fertilizer alone. The control consisted of the application of the Bokashi compost under the usual conditions of cultivation. Plant growth was assessed by biomass increase measured as dry weight, production, and leaf area. The physicochemical analysis of soil included: percentage of organic carbon, water content, and pH. Results. The inoculation of the bio-fertilizer produced an increase in the rate of mineralization of compost, reaching a final 4.85% of OC between 90 and 180 days after inoculation. There were significant (p< 0.05) differences between biomass production with T2 (1,538 kg ha-1) and the control (477 kg ha-1). Regarding the soluble solid content, T1, T3 and T4 showed the highest °Brix values (12.4, 12.35 and 12.15, respectively). Conclusions. The concentration of 30 ton ha-1 produced the highest biomass production and the application of the biofertilizer showed a positive correlation with compost mineralization and glucoside synthesis...

Influência da matéria orgânica e Azotobacter nigricans em uma cultura de Stevia rebaudiana B. Stevia rebaudiana é uma planta que acumula um composto edulcorante não-calórico conhecido como esteviosídeo. Sua cultura é tradicionalmente fertilizada com produtos químicos que danificam o ecossistema, forçando a procura de alternativas orgânicas para reduzir esse dano. Objetivo. Avaliar o efeito da matéria orgânica e um biofertilizante com base em Azotobacter nigricans numa cultura de Stevia rebaudiana localizada no departamento de Meta, na Colômbia. Materiais e métodos. Cinco tratamentos foram estabelecidos: T1 e T2 incorporando ao cultivo composto de lixo doméstico em concentrações de 15 e 30 t ha-1, respectivamente; T3 e T4 com as mesmas concentrações do composto e inoculando o biofertilizante e T5 apenas com o biofertilizante. O controle correspondeu a condições normais de cultivo com composto Bokashi. O crescimento das plantas foi avaliado por estimação da biomassa em peso seco, da produção e da área foliar. A análise físico-química do solo inclui o seguinte: porcentagem de carbono orgânico, umidade e pH. Resultados. A inoculação do biofertilizante produz um aumento na taxa de mineralização do composto, com CO final de 4,85% entre 90 e 180 dias. Diferenças estatisticamente significativa (p <0,05) foram observadas entre a produção de biomassa de T2 (1538 kg ha-1) e o controle (477 kg ha-1). Com relação ao conteúdo de sólidos solúveis T1, T3 e T4 tiveram os maiores valores de °Brix (12,4: 12,35 e 12,15). Conclusões. A concentração de 30 ton ha-1 apresentou o melhor rendimento de biomassa e a aplicação do biofertilizante mostrou uma correlação positiva com a mineralização do composto e a síntese de glicosídeos...

El sorprendente legado que nos dejó el sabio Moisés Bertoni: el Ka’a He’ê / The amazing legacy left by the wise man Moises Bertoni: the Ka'a He'e

El esfuerzo del científico Moisés Santiago Bertoni por sistematizar parte de la riqueza que tiene el Paraguay, se refleja en la Stevia rebaudiana Bertoni, (Ka'a He'ê), una planta que hace parte de la identidad como nación, pero que al mismo tiempo, luego de un siglo, sigue siendo promisoria como elemento fundamental para la implementación de un modelo de desarrollo sostenible en áreas rurales.

The effort of the scientific Moisés Santiago Bertoni to systematize part of the richness of Paraguay is reflected in the Stevia rebaudiana Bertoni, (Ka'a He'ê). This plant makes part of the identity of the nation but at the same time, after a century, is still promising as an essential element for the implementation of a sustainable development model in rural areas.

Longevidade pós-colheita de alpínia [Alpinia purpurata (Vieill.) K. Schum.] tratada com soluções de sacarose e extratos aquosos naturais / Postharvest longevity of red ginger [Alpinia purpurata (Vieill.) K. Schum.] treated with sucrose solutions and natural water extracts

A alpínia (Alpinia purpurata) é uma planta tropical encontrada em diversas regiões do Brasil com excelente potencial para a comercialização como flor de corte. Entretanto, a senescência das hastes pela exaustão da sacarose é um dos principais fatores que afetam a durabilidade comercial, sendo suprimida através da adição de sacarose nas soluções de pulsing. O presente trabalho objetivou avaliar o efeito de extratos aquosos de estévia (Stevia rebaudiana), anis estrelado (Illicium verum) e sacarose em solução de pulsing na manutenção da qualidade pós-colheita de inflorescências de alpínia. Hastes florais uniformizadas em tamanho foram submetidas à solução de pulsing, por 12 horas, nas concentrações de 0,5; 1,0; 2,0 e 3,0 por cento, tendo água destilada como controle. A melhor qualidade comercial das inflorescências foi obtida quando as hastes foram colocadas em pulsing em extratos de anis estrelado e estévia 1 por cento e em solução de sacarose 2 por cento, não apresentando diferença estatística entre si. A longevidade total das hastes não foi influenciada pelos tratamentos. A solução de sacarose pode ser substituída pelos extratos das plantas medicinais estudadas, na conservação pós-colheita de inflorescências de alpínia.

Red ginger (Alpinia purpurata) is a tropical plant found in several Brazilian regions with excellent potential for commercialization as cut flower. However, the senescence of flower stems due to the exhaustion of sucrose is a major factor that affects commercial durability and is suppressed through addition of sucrose in pulsing solutions. The aim of this work was to evaluate the effect of water extracts from stevia (Stevia rebaudiana), star anise (Illicium verum) and sucrose in pulsing solution on the postharvest quality maintenance of red ginger inflorescences. Flower stems of uniform size were subjected to the pulsing solution for 12h at 0.5, 1.0, 2.0 and 3.0 percent concentrations, with distilled water as control. The best commercial quality of inflorescences was obtained when flower stems were kept in pulsing solutions from 1 percent star anise and stevia extracts and in 2 percent sucrose solution, not presenting statistical difference. Total longevity of flower stems was not influenced by treatments. Sucrose solution may be replaced by extracts of the studied medicinal plants in the postharvest conservation of red ginger inflorescences.

Evaluación del contenido de esteviósido y rebaudiósido A en una población de Stevia rebaudiana Bertoni (kaâ heê) cultivada comercialmente: estudio preliminar / Evaluation of the content of stevioside and rebaudioside A in a population of Stevia rebaudiana Bertoni (kaâ heê) commercially cultivated: a preliminary study

Stevia rebaudiana Bertoni (kaâ heê) es un arbusto originario de la Región Oriental de Paraguay. Sus hojas contienen glucósidos diterpénicos que producen un sabor dulce, perosin valor calórico y son de 150 a 300 veces más dulces que la sacarosa (solución al 0,4%). Durante las temporadas agrícolas 1998 y 1999 se establecieron sembrados deselección individual, en el Instituto Agronómico Nacional (Caacupé, Paraguay). El objetivo de este trabajo fue determinar el contenido de esteviósido y rebaudiósido A en plantasseleccionadas en campo a fin de evaluar la variabilidad existente en la población e identificar clones con alto contenido de dichos glucósidos. De una población original de 2000 individuos, se seleccionaron fenotípicamente 140 plantas por características agronómicas superiores y se cosecharon en etapa de prefloración y libres de polinización.En los Laboratorios del Instituto Nacional de Tecnología Normalización y Metrología (INTN) fueron evaluados los contenidos de esteviósido y rebaudiósido A por detección por cromatografía liquida de alta resolución. El contenido de esteviósido fluctuó entre 0 y 21 % concentrándose el 92 % de la población entre valores del 5 al 15 % .En cuanto al contenido de rebaudiósido A se obtuvieron valores entre 0 y 12 % correspondiendo al 68% de la población un contenido entre 3 y 9 %. La demanda actual de stevia se halla en creciente aumento, por lo que las acciones orientadas a establecer líneas clonales con alto contenido de principios edulcorantes permitirá a los productores primarios la obtención decultivos más productivos e incrementara el rendimiento de obtención de glucósidos.

Stevia rebaudiana Bertoni (kaâ heê) is a bush native to the Eastern Region of Paraguay. Its leaves contain diterpene glycosides that produce a sweet taste but without any caloric value and are 150 to 300 times sweeter than sacharose (0, 4% solution). During 1998 and 1999 agricultural seasons, individual selection sown fields were established in the National Agronomical Institute (Caacupé, Paraguay). The objective of this work was todetermine the content of stevioside and rebaudioside A in these selected plants in the field in order to evaluate the variability existent in the population and identify clones with high content of those glycosides. Of an original population of 2,000 specimens, 140 plants were selected phenotipically by the superior agronomical characteristics and they were harvested in the period of pre-flowering and were pollination free. The content of stevioside and rebaudioside A were evaluated in the laboratories of the National Instituteof Technology, Standardization and Metrology (INTN in Spanish) by high resolution liquid chromatography. The content of stevioside ranged from 0 to 21% concentrating the 92% of the population between 5 to 15%. In relation to rebaudioside A, values between 0 and 12% were obtained being 68% of the population between a content of 3 to 9%. As the current demand of Stevia is increasingly rising, the actions oriented to establish clonallines with high content of sweetener principles will allow primary producers to obtain more productive cultivations and increase the output of glycoside obtainment.

SINTESIS DE ESTEVIOSIDOS EN ESTEVIA (Stevia rebaudiana Bert.) / STEVIOSIDE SYNTHESIS IN STEVIA (Stevia rebaudiana Bert)

Stevia rebaudiana Bert. es una planta selvática subtropical nativa de Paraguay, que posee un potente edulcorante de hasta 300 veces más dulce que la sacarosa y no tiene calorías. Las moléculas responsables de esta característica son glucósidos de diterpeno, presentes en hojas y sintetizados, al menos en los estados iniciales, usando la misma ruta de síntesis del ácido giberélico, en la que el ácido shiquímico, da origen a muchos compuestos aromáticos. El acetato es el precursor de los terpenos o isoprenoides por la ruta del acetato-mevalonato, donde se encuentran los esteviósidos, aunque en este artículo se discute una ruta alternativa. La presente actualización pretende aportar algunas herramientas para el entendimiento de las principales rutas de síntesis de los glucósidos de esteviol.

Stevia rebaudiana Bert. is a subtropical wild plant of Paraguay , that possesses a potent sweetener up to 300 times higher than sucrose and has no calories. The molecules responsible for these characteristics are diterpen glycosides, found in leaves and synthesized at least, at initial states, which use the same pathway of the gibberellic acid in which the shiquimic acid gives origin to many aromatic compounds. The acetate is the precursor of the terpens or isoprenoids through the acetate-mevalonate pathway, where steviosides are found. Although in this article, an alternative route is discussed. This updating pretends to contribute tools for the understanding of the main pathways of steviol glycosides synthesis.