Influência do resíduo fibroso da moagem de milho micropulverizado na biodisponibilidade de ferro, zinco e cálcio em ratos

• Autor(a) principal: Oliveira Junior, Gilson Irineu de
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/2715
• topic: Fibra alimentar; Milho; Ferro; Cálcio; Zinco; Fiber source; Corn; Iron; Calcium; Zinc; CNPQ::CIENCIAS DA SAUDE::NUTRICAO

Corn is the main cereal produced in Brazil. The average national annual per capita intake is approximately 7.7 kg and its importance in the economy is related to the various ways it is used. A fibrous residue is accumulated in the milling industry, which correspond to % of the kernel, and is still not well investigated and used in Brazil. The present study aimed at to determine the nutritional composition of the corn bran and its effects on the bioavailability of iron, calcium and zinc in rats. Iron bioavailability was analyzed by the method of depletion and repletion of hemoglobin. The animals were fed an iron-free diet for 21 days (depletion), and them, they were placed in a repletion diet containing 6, 12 or 24 ppm iron as ferrous sulfate, and cellulose (Control) or corn bran (Test) as sources of fiber for 14 days. Calcium and zinc bioavailability was analyzed in rats fed cellulose or corn bran as source of fiber and 50 or 100% of the recommended intake of these minerals. At the end of 42 days, food intake (FI), body weight gain (BWG), mineral balance, fecal, bone, plasma and erythrocite mineral contents were analyzed. The product showed high content of total dietary fiber (73.4 g.100 g-1), and insoluble fiber (72.7 g.100 g- 1). It also contained carbohydrate (12.5 g.100 g-1), proteins (5.5 g.100 g-1), lipids (5.5 g.100 g-1), zinc (2.49 mg.100 g-1), iron (2.73 mg.100 g-1), 121 kcal.100 g- 1, and low content of phytate (1.97 μmol. g-1). Regarding the bioavailability of iron, the levels of hemoglobin, hematocrite and hemoglobin gain differ among different levels of iron (p≤0.01) but not among the diets with different sources of fiber (p>0.05). The interaction between source of fiber and level of iron was also not significant (p>0.05). The relative biological value of the Test group was 104% in relation to the Control, which suggests that the diet containing corn bran was comparable to that containing cellulose. Concerning calcium bioavailability, BWG, FI and food efficiency ratio (FER) varied according to the interaction between source of fiber and the level of mineral in the diet (p≤0.05), with higher BWG at 50% calcium consumption and corn bran diet. Femur weight (FW), bone length (BL) and calcium concentration in bone (BCa) varied according to the source of fiber (p≤0.01), with higher means for corn bran diet. The interaction between source of fiber and level of calcium was significant for calcium balance (p≤0.05), and was higher for the diet with corn bran and 50% calcium. Fecal and plasma calcium, calcium absorption and retention varied with the level of the mineral in the diet, which were higher (p≤0.05) in the diets at 50%, except for fecal calcium which was higher at 100% calcium. In the study of zinc bioavailability, BWG, FI and FER varied with the level of the mineral in the diet (p≤0.05), with higher means at 50% zinc. Fecal zinc was higher for cellulose diet and did not differ among different levels of zinc. Bone zinc was higher in the cellulose diet and also in the diet with 100% zinc irrespective to the source of fiber. Erytrhocite zinc varied only with the level of zinc, and was higher at 100% intake. It is concluded that corn bran is a potential alternative source of fiber for human diet, without adverse effects on iron, calcium and zinc bioavailability.