ABSTRACT
ABSTRACT Objective: To develop a natural dietary product with functional benefits for diabetic patients. Whey protein concentrate was obtained through the separation membrane processes and sweetened with rebaudioside A. This product was submitted to sensory testing in humans and used to evaluate possible functional properties in male Wistar rats models with diabetesMellitus induced by streptozotocin. Methods: Two concentrates were produced. Only the second showed protein content of 74.3 and 17.3% of lactose was used as supplementation in induced diabetic rats. This concentrate was obtained from the concentration by reverse osmosis system (180 k Daltons), followed by nanofiltration in a 500 k Daltons membrane and spray drying at 5.0% solution of the first concentrate developed. The concentrate was sweetened with rebaudioside A (rebaudioside A 26 mg/100 g concentrate). All procedures were performed at the Center for Studies in Natural Products, at the Universidade Estadual de Maringá. Three experimental groups were established (n=6): two groups of diabetic animals, one control group and one supplemented group; and a control group of normal mice (non-diabetic). The supplemented group received concentrates sweetened with rebaudioside A in a dose of 100 mg/kg bw/day by an esophageal tube for 35 days. Fasting, the fed state and body weight were assessed weekly for all groups. At the end of the supplementation period, the following were analyzed: plasma parameters of glucose, total cholesterol, triglycerides and fructosamine; the serum levels of aspartate aminotransferase and alanine aminotransferase, water and food intake. Organs and tissues were removed and weighed to assess mass and anatomical changes. Results: The product presented 74% of proteins and 17% of lactose and showed satisfactory sensory testing by the addition of 26 mg of rebaudioside A/100 g concentrate. Supplementation of the product reduced hyperglycemia, plasma fructosamine levels, triglycerides and total cholesterol, and improved body weight gain of streptozotocin-induced diabetic rats. Conclusion: Whey protein concentrate with substantial content of protein (above 70%) and low lactose was obtained through the membrane separation processes. The addition of rebaudioside A at the concentration of 26 mg/100 g rebaudioside A proved to be as sweet as sucralose with satisfactory sensory testing, which indicates that this is a non-caloric natural sweetener that can replace artificial sweeteners. The product (whey protein concentrate sweetened with rebaudioside A) presented important functional properties and reduced the metabolic disorders caused by the syndrome.
RESUMO Objetivo: Obtenção de um concentrado proteico do soro do leite por meio de processos de separação por membranas, adoçado com rebaudiosídeo A, análise sensorial em humanos e avaliação de propriedades funcionais em modelos de ratos induzidos por estreptozotocina. Métodos: Foram produzidos dois concentrados, mas apenas o segundo, que apresentou teor proteico de 74,3 e 17,3% de lactose, foi utilizado na suplementação de animais diabéticos. Esse concentrado foi obtido a partir da concentração em sistema de osmose reversa (180 Daltons), seguida de nanofiltração em membrana de 500 Daltons e secagem emspray dryer de uma solução a 5% do primeiro concentrado desenvolvido. O concentrado foi adoçado com rebaudiosídeo A (26 mg de rebaudiosídeo A/100 g de concentrado) obtido por meio da extração, separação e purificação das folhas de Stevia rebaudiana. Todos os processos foram realizados no Núcleo de Estudos em Produtos Naturais, da Universidade Estadual de Maringá. Foram estabelecidos três grupos experimentais (n=6): dois de animais diabéticos, um controle e outro suplementado; e um grupo de animais não diabéticos controle. O grupo suplementado recebeu o concentrado adoçado com rebaudiosídeo A na dose de 100 mg/kg peso corporal/dia, por sonda esofágica, por um período de 35 dias. Em todos os grupos, foram avaliadas semanalmente as glicemias de jejum e no estado alimentado, e o peso corporal. Ao final do período de suplementação, os parâmetros plasmáticos de glicose, colesterol total, triglicérides e da frutosamina; os valores séricos de aspartato aminotransferase e alanina aminotransferase e a ingestão hídrica e alimentar foram analisados. Órgãos e tecidos foram retirados e pesados a fim de se avaliarem alterações de massa e anatômicas. Resultados: O produto formulado apresentou 74% de proteínas e 17% de lactose e apresentou perfil sensorial satisfatório por meio da adição de 26 mg de rebaudiosídeo A/100 g de concentrado. A suplementação do produto reduziu a hiperglicemia, os níveis plasmáticos de frutosamina, triglicérides e colesterol total e ainda melhorou o ganho de peso corporal dos ratos diabéticos induzidos. Conclusão: Os processos de separação por membranas utilizados neste estudo proporcionaram a obtenção eficiente de um concentrado proteico do soro do leite, com teor proteico importante, superior a 70% e com baixo teor de lactose. A adição de rebaudiosídeo A ao produto na concentração de 26 mg/100 g de rebaudiosídeo A proporcionou dulçor equivalente ao da sucralose, com perfil sensorial satisfatório, o que indica que esse edulcorante natural não calórico tem potencialidade para substituir os artificiais. O produto obtido (concentrado proteico do soro do leite adoçado com rebaudiosídeo A) apresentou propriedades funcionais importantes, reduzindo alguns distúrbios metabólicos decorrentes dessa síndrome.
Subject(s)
Animals , Male , Rats , Diabetes Mellitus, Experimental/drug therapy , Whey Proteins/therapeutic use , Rats, WistarABSTRACT
BACKGROUND: Rebaudioside A and erythritol are nonnutritive sweeteners. There have been several studies of their glycemic effects, but the outcomes remain controversial. The purpose of this study was to evaluate the glycemic effects of rebaudioside A and erythritol as a sweetener in people with glucose intolerance. METHODS: This trial evaluated the glycemic effect after 2 weeks of consumption of rebaudioside A and erythritol as sweeteners in a pre-diabetic population. The patients were evaluated for fructosamine, fasting plasma glucose, C-peptide, insulin, and 2-hour plasma glucose before and after consumption of sweetener. The primary outcome was a change in fructosamine levels from the baseline to the end of treatment. Secondary outcomes were the changes in levels of fasting plasma glucose and 2-hour plasma glucose. RESULTS: From the baseline to the end of experiment, the changes in fructosamine levels after consumption of rebaudioside A and erythritol, did not differ significantly (244.00±19.57 vs. 241.68±23.39 µmol/L, P=0.366). The change in levels from the baseline to end of the study for rebaudioside A and erythritol were fasting plasma glucose (102.56±10.72 vs. 101.32±9.20 mg/dL), 2-hour plasma glucose (154.92±54.53 vs. 141.92±42.22 mg/dL), insulin (7.56±4.29 vs. 7.20±5.12 IU/mL), and C-peptide (2.92±1.61 vs. 2.73±1.31 ng/mL), respectively, and also did not differ significantly (P>0.05 for all). CONCLUSION: Our study suggests that consumption of rebaudioside A and erythritol does not alter the glucose homeostasis in people with glucose intolerance.
Subject(s)
Humans , Blood Glucose , C-Peptide , Erythritol , Fasting , Fructosamine , Glucose Intolerance , Glucose , Homeostasis , Insulin , Sweetening AgentsABSTRACT
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.
ABSTRACT
Hydrolysis studies of the two diterpene glycosides stevioside and rebaudioside A that were isolated from Stevia rebaudiana were performed using acid and alkaline conditions. Acid hydrolysis was carried out using H2SO4 whereas alkaline hydrolysis was performed using NaOH. Using these methods, partial hydrolyzed glycosides of stevioside and rebaudioside A and their sugar residues were identified from the alkaline and acid hydrolysis studies respectively. The structures of the acid and alkaline hydrolysis products were achieved on the basis of extensive NMR and high resolution mass spectral data, and in comparison with the data reported in the literature as well as TLC comparison with their corresponding standard compounds.
ABSTRACT
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.