Juciane de Abreu Ribeiro Pereira

Studies of chemical and enzymatic characteristics of Yacon (Smallanthus sonchifolius) and its flours

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.

Characterization of food bars manufactured with agroindustrial by-products and waste

Food bars are products obtained from the union of a number of components, standing out in the snack category due to their portability attribute with a focus on convenience and health. Utilization of by-products and agroindustrial food waste as ingredients in the making of food bars is highly important due to the utilization of leftovers of marked nutritional and functional value and decrease of the production cost. This work intended to evaluate the chemical and physicochemical aspects of food bars made with the by-products broken rice (BR) and pequi nut (PN), soybean extract residue (SER), and pineapple waste (PW). Distinct proportions of BR: SER respectively were used, amounting to five treatments: 1:0 (A); 3:1 (B); 1:1 (C); 1:3 (D) and 0:1(E) and fixed amounts of the other components. For the statistical analysis, variance analysis and the Tukey test were performed to 5% significance. The moisture, protein, lipid, ash, mineral, and dietary fiber contents were directly increased as the SER was increased and the amount of BR was decreased. However, the opposite was found with both carbohydrates and calories. The soluble solids, pH and water activity values presented increases with the increased soybean extract residue. All the treatments presented slightly acidic pH and water activity bellow 0.6, favoring microbiological safety. In the chemical score, treatment A presented lysine as the limiting aminoacid in relation to the Food and Agriculture Organization - FAO/WHO reference (1990). The food bars can be considered rich in dietary fiber and with considerable nutritional support. Treatments D and E proved better in the set of the variables studied for human consumption.

Effects of the kefir and banana pulp and skin flours on hypercholesterolemic rats.

PURPOSE To investigate the effect of kefir and banana pulp and skin flours on the serum levels of total cholesterol, HDL-c, LDL-c and triacylglycerols in rats fed cholesterol-rich diet. METHODS Thirty Male Wistar rats were used. In the first 21 days, the animals were fed purified hypercholesterolemic diets, except the standard group. In the next 21 days, the animals were given modified diets: Group GC: standard diet AIN-93G; Group HIP: hypercholesterolemic diet; Group F: hypercholesterolemic diet added of 1% of banana skin flour and 7% of banana pulp flour; Group Q: hypercholesterolemic diet plus kefir suspension by oral infusion (1.5 ml/animal); Group FQ: hypercholesterolemic diet added of 1% banana skin flour and 7% of banana pulp flour plus kefir suspension (1.5 ml/animal). RESULTS In spite of the high fiber content, the addition of banana pulp (7%) and skin (1%) flour did not alter the plasma levels of total cholesterol, HDL-c and LDL-c. However, they reduced the TG levels in 22%. Already fermented kefir reduced significantly the levels of VLDL, LDL-c and triacylglycerols, in addition to having increased HDL-c. However, it was not possible to verify the symbiotic effect between both. CONCLUSION The results reinforce the beneficial effects of kefir in reducing the risks of cardiovascular diseases.

Total antioxidant activity of yacon tubers cultivated in Brazil

Yacon (Smallanthus sonchifolius) e uma raiz tuberosa da regiao andina na America do Sul, rica em agua, frutooligossacarideos e compostos fenolicos, alguns dos quais sao antioxidantes naturais e podem auxiliar a prevenir a acao deleteria dos radicais livres no organismo. O yacon tem atraido muita atencao devido a seus potenciais beneficios de saude para os seres humanos. Neste estudo, os niveis de fenolicos totais, taninos, acidos fenolicos e atividade antioxidante total foram mensurados na casca e polpa de tuberas de yacon ambas nas formas fresca e de farinha. As farinhas de yacon apresentaram altas concentracoes de fenolicos totais e taninos, especialmente a farinha da casca. A farinha da polpa de yacon destacou-se como a principal fonte de acidos fenolicos, principalmente cafeico e acido clorogenico. A atividade antioxidante total avaliada pelos metodos DPPH (2,2-Difenil-1-picril-hidrazil) and ABTS (2,2′-Azino-bis (3-etilbenzotiazolina-6-acido sulfonico)) foi maior na farinha de casca de yacon. A atividade antioxidante total foi correlacionada com o conteudo de fenolicos totais e taninos pelos metodos DPPH e ABTS. Estes resultados sugerem que yacon pode ser usado como uma fonte alimentar alternativa de compostos fenolicos que auxiliam a prevenir processos degenerativos causados pelo estresse oxidativo, especialmente na forma de farinhas.

Chemical composition of unripe banana peels and pulps flours and its effects on blood glucose of rats

Purpose 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. Design/methodology/approach 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). Findings 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. Originality/value 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.

Changes in glucose levels and fecal excretion of lipids due to consumption of yacon flour

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.

Effect of different commercial fat sources on brain, liver and blood lipid profiles of rats in growth phase

PURPOSE To investigate the fatty acid content of different fat sources and evaluate the effect of them on plasma and hepatic lipids and on the fatty acid profile of the brain tissue of Wistar rats. METHODS Thirty male albino Wistar rats received for 59 days, the following diets: diet added of margarine with low content of polyunsaturated fatty acids (PUFA); diet added of margarine with high content of PUFA; diet added of butter; diet added of hydrogenated vegetable fat; diet added of soybean oil. Fatty acid profile of the lipid sources, blood and hepatic lipids fractions and fatty acid profile of the brain tissue were determined. RESULTS Margarine consumption of provided different responses as to concentrations of blood and hepatic lipid fractions. Intake of butter and hydrogenated increased LDL-c/HDL-c ratio, being the steepest increase promoted by hydrogenated vegetable fat, which also raised LDL-c levels expressively. All fats used in the treatments reduced the cerebral concentration of docosahexaenoic acid when compared to soybean oil (control). CONCLUSION The different fat sources commonly consumed by population provided different responses in vivo. This is particularly relevant considering the role of these lipids in the incidence and prevention of cardiovascular diseases.