Osmotic dehydration using different polyols was studied. Yacon slices were immersed in solutions of xylitol, maltitol, erythritol, isomalt and sorbitol. The kinetics of solid gain (SG), water loss (WL) and water activity (aw) were evaluated (0, 10, 30, 45, 60, 90 and 120 min). The effective diffusion coefficients of water (Deffw) and solids (Deffs) were calculated with the models of Fick and Barbosa Júnior et al. At the end of the process, the highest SG was obtained with erythritol solutions; the lowest with sorbitol and maltitol and intermediate values of SG were acquired in osmotic processes with solutions of isomalt and xylitol. The samples treated in sorbitol, xylitol and erythritol solutions presented the highest Deffw and were more effective at increasing WL and reducing aw. The model of Barbosa Júnior et al. presented the best fitness. The Deffw/Deffs ratio showed better results for osmotic processes involving sorbitol and xylitol. Practical Applications Yacon tuber is typical from Latin America. It is considered an important source of fructooligosaccharides (FOS). This class of carbohydrate is employed on the control of diseases such as obesity and diabetes, due its low glycemic index. However, yacon roots are highly perishable and techniques for conservation are required. Osmotic dehydration is a pretreatment process that provides partial water removal from a food product, with low energy consumption. Polyols are widely employed as osmotic agents due their low caloric value. The kinetics of mass transfer on osmotic process are function of process variables, sample matrix characteristics, molecular weight of osmotic agents and others. This study investigate the water loss, solid gain, effective diffusivity and water activity of the OD of yacon with five different polyols and provide information about mass transfer kinetics of osmotic processes using two different empirical models.

Resumo Os hábitos alimentares de adolescentes têm sido marcados pelo alto consumo de alimentos ricos em gorduras, sódio e açúcares simples que, somados ao sedentarismo, estão diretamente relacionados com a incidência de obesidade entre outras doenças crônicas não transmissíveis tanto nesta faixa etária como na vida adulta. Este cenário reforça a urgência de se adotar programas de educação alimentar e nutricional (EAN). Sabendo-se disso, o objetivo deste trabalho foi identificar o hábito alimentar e sequencialmente avaliar o grau de conhecimento sobre alimentação e nutrição de adolescentes, intervir com EAN, aplicando dois recursos pedagógicos distintos (palestra e jogo do tipo quiz) e comparar a eficácia de ambos no processo educativo. Participaram do estudo 59 adolescentes entre 13 e 16 anos, matriculados em duas turmas da oitava série de uma escola municipal do município de Lavras – Minas Gerais. Os resultados indicaram prevalência de padrão alimentar inadequado evidenciando o consumo elevado de alimentos ricos em gorduras e açúcares simples. Tanto a aplicação do jogo como a palestra se mostraram eficientes para aumentar o grau de conhecimento dos adolescentes e, quando comparados, os métodos não mostraram diferença significativa entre si.

The osmotic dehydration assisted by ultrasound (ODAU), in low temperatures, reduces water activity (a w ) and maintains nutrients. The influence of solution concentration (SC, 20 to 60 Brix, xylitol and sorbitol) and ultrasound application time (t us , 0 to 40 min) in ODAU of yacon was studied with the aid of a response surface method. The optimum condition with respect to mass transfer parameters, a w and fructan retention was SC of 60 Brix for both solutions, t us of 2.67 min for xylitol samples and 0 min for sorbitol samples.The application of ultrasound improve dehydration, but could carries out to depolymerisation fructans.

Sprouted and fermented foods have shown hypoglycemic effects on humans and animals, by reducing concentrations of soluble carbohydrates, and increasing dietary fiber and resistant starch content. In this study, diets with high levels of simple carbohydrates supplemented with toasted quinoa flour, sprouted and toasted quinoa flour, fermented and toasted quinoa flour or sprouted/fermented and toasted quinoa flour were given to Wistar rats. During the experiment, the glycemic index (GI) of the diets were measure and, at the end of 47 days of feeding, the effects of the diets on physical and biochemical parameters of the animals were evaluated. Results indicated that the processes of sprouting and/or fermentation potentiate the ability of quinoa to reduce GI of diets with high levels of simple carbohydrates. Moreover, food intake, blood glucose and lipid levels, and accumulation of epididymal adipose tissue were reduced in rats fed diets supplemented with quinoa. These effects may be due to the nutritional composition of the supplemented diets, besides the chemical changes promoted by processing quinoa. These results are particularly relevant once sprouted and fermented quinoa could be an alimentary source of interest, especially for disease risk prevention such as diabetes, obesity and dyslipidemias.

No abstract

Due to the importance of studies on yacon related to health, its in natura pulp, in natura peel, pulp flour, and peel flour were chemically analyzed in terms of its centesimal composition, specific minerals, total dietary fiber and fractions, pH, total soluble solids, total titratable acidity, tannins, oxalic acid, and nitrate. The polyphenoloxidase and peroxidase enzymatic activities were evaluated for in natura pulp and peel only. Yacon pulp and peel flour presented average yield of 7.94% and 10.86%, respectively. The in natura pulp presented a higher moisture and carboydrate content and lower lipid, protein, total dietary fiber, and ash than those of the peel flour. The same pattern was observed for pulp flour when compared to peel flour. The highest tannin, nitrate, and oxalic acid levels were found in the peel flour, 15,304.5 mg.kg-1, 1,578.3 mg.kg-1, and 7,925.0 mg.kg-1 (wet weight), respectively. The polyphenoloxidase and peroxidase enzymes presented higher enzymatic activity in the yacon peel. Based on the results obtained, it can be said that the yacon and its derivatives are important dietary carbohydrate and mineral sources and contain antinutritional substance contents lower than those harmful to health.

Purpose As studies investigating the effects of fructan sources, such as yacon, on glucose and lipid metabolism showed different results, additional research is required to establish a clear relationship between them. Thus, this paper aims to evaluate possible effects of the consumption of the yacon pulp flour (YPF) on biological and metabolic parameters such as food consumption, weight gain, serum glucose levels and fecal lipid excretion of rats, as well as determine the role of glycemic index (GI) of the diets added of this ingredient on those parameters. Design/methodology/approach For this purpose, 24 male albino Wistar rats were divided into four groups, which received the following treatments for 17 days: Group 1 (G1) (Control) – American Institute of Nutrition (AIN)-M; Group 2 (G2) – AIN-M added 5 per cent YPF; Group 3 (G3) – AIN-M added 10 per cent YPF and Group 4 (G4) – AIN-M added 15 per cent YPF. Analysis of fasting and postprandial glycemia was conducted for elaboration of the glycemic curve and calculation of the GI of the diets. Lipids loss was measured by quantification of crude fat in feces after consumption of the diet. Findings YPF, regarding the concentration in the diets, did not elevate the fasting glucose among the groups. The postprandial glucose of the animals declined in different postprandial glucose peaks of the groups ingesting YPF in relation to the control one, especially in group treated with 15 per cent YPF, between 30 and 60 min (p <0,05), confirming the influence of the dietary fiber on the absorption of the glucose. The ingestion of YPF increased dragging of lipids to the animal feces, proportional to the amounts of YPF added to the diets. According to the regression analysis, followed by regression testing to 5 per cent, there was a significant difference between the experimental groups, being that the elevation of the percentage of YPF added to the diet caused a proportional increase in the lipid levels in the animal feces. Originality/value YPF could be an alimentary source of interest, mainly when the focus is on disease risk prevention such as diabetes, obesity and dyslipidemias.

RESUMOConduziu-se o presente estudo, com o objetivo de avaliar o efeito de diferentes tipos de fibras sobre as fraçoes lipídicas do sangue e fígado de ratos. Para determinar o efeito da pectina citrica, goma guar e celulose sobre o perfil lipidico dos ratos utilizaramse 36 ratos machos da linhagem wistar. Os ratos foram distribuidos aleatoreamente em seis grupos. Cada gruopo foi submetido a uma dieta por 58 dias. As dietas utilizadas foram: A-10% de pectina, B -15% de pectina, C -10% de goma guar, D-15% de goma guar, E -5% de Celulose sem colesterol e F -5% celulose com 1% de colesterol. A pectina e a goma guar evitaram o aumento do colesterol total e LDL-c sérico observado na dieta F (p<0,05). Não houve diferença significativa entre os tipos de fibras e a quantidades utilizadas. Os níveis séricos HDL-c, VLDL-c e TAG permaneceram inalterados em todos os tratamentos. Os resultados mostram o potencial efeito benéfico da ingestão das fibras solúveis pectina e goma guar no controle da colesterolemia.Termos para indexação: Fibra alimentar, pectina, goma guar, hipercolesterolemia, sangue, fígado, rato. ABSTRACTThe present study was designed to evaluate the effect of different types of fibers on lipid portions of mice blood and liver. To determine the effect of citric pectin, guar gum and cellulose on the rat lipid profile, 36 male mice of the Wistar strain were utilized. The mice were allocated randomly into six groups. Each group was submitted to an experimental diet for 58 days. The utilized diets were: A-10% pectin, B -15% pectin, C -10% guar gum, D-15% guar gum, E -5% cellulose with no cholesterol and F -5% cellulose with 1% cholesterol. Pectin and guar gum prevented the increase of total cholesterol and serum LDL-c found in diet F (p<0.05). There was no significant difference among the types of soluble fibers and the amounts utilized. The serum levels HDL-c, VLDL-c, and TAG did not alter in all the treatments. The results show the potential beneficial effect of the ingestion of the soluble fibers pectin and guar gum in cholesterolemia control.