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Flours obtained from pulps and peels of unripe banana were evaluated regarding their chemical composition and glycemic responses in rats. Moreover, this study aims to propose a new assay to measure glycemic responses using animals.

Proximal composition, total dietary fiber and its insoluble and soluble fractions, mineral content and tannins were evaluated. Glycemic responses were measured using albino Wistar rats (seven animals/group).

Flours from pulp and peel of unripe banana presented high content of carbohydrates and minerals. Moreover, flour from peel was rich in insoluble fiber, whereas flour from pulp had adequate proportion of insoluble and soluble fractions. Consumption of banana flours from peel and pulp did not affect fasting blood glucose of normoglycemic rats. Flour from pulp, when consumed in concentrations of 10 and 15 per cent of the diet, significantly stimulated lower glycemic responses in the animals.

Results presented in this study disclose unripe banana flour as an interesting food source, which may be indicated for preventing some types of diseases, such as diabetes, obesity and dyslipidemia. Moreover, the glycemic index assay using animals promoted accurate answers, as the diets were standardized, unlike studies with humans, which do not control variations related to omission and distortion of information regarding food intake.

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.

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.

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.

YPF could be an alimentary source of interest, mainly when the focus is on disease risk prevention such as diabetes, obesity and dyslipidemias.