Caracterização bromatológica de grãos de cevada e efeito da fibra alimentar na resposta biológica de ratos

Abstract

There is an increasing human interest for foods which have components that can influence the physiological and the metabolic activities. Furthermore, researchers have been interesting in enriched foods with isolated substances proprieties. Taking it into consideration the barleys grains potentiality to human´s consume can be fit in the functional food category because of its high level of dietary fiber with soluble fiber and its β-glucan. Therefore, this work aims to determine the chemical compositions of different barley grains cultivars, covered and hulless types, and it also aims to classify in groups with distintive nutritional characteristics, as well as to relate the effects of hulless barleys grains inclusion as fiber source on diets. This experiment will be applied in growing rats as a biological model. To do this, we have analysed the crude protein, ash, ether extract, total fiber, soluble fiber, insoluble fiber and non-fibrous carbohydrate in 17 barleys cultivars. To evaluate the biological effects, we used male Wistar rats; it was feed with formulated rations. This rations was prepared with barleys grains of two (2), cultivars selected, because it has similar level of total fiber, but with different soluble fiber/insoluble fiber and control ration formulated based on the AIN-93. The animals have been submitted to an adapted period of five (5) days, and we collected samples during twenty tree (23) experimental days to determine the dry matter, body weight, fecal water content, fecal pH, fecal excretion of nitrogen, total fiber and insoluble fiber. The results showed significative differences among integral cultivars to crude protein, ash, ether extract, total fiber and non-fibrous carbohydrates, but there isn´t difference in the soluble and insoluble fiber content, while in the hulless grains, we can find differences in the analysed parameter. The values´average of weight and the feed conversion didn´t difere in treatment and it was attributed to consume´s similarity of rations and due to the digestibility of dry matter in experimental rations. Variations in the bromatological composition measure occurs because of the genetic variability of cultivars and the hulless, thus barley´s grains can be used with different objectives in the human and animal nutrition. The favorable biological effects to barley´grains, as a fiber source, it has increased the water content and nitrogen in feces, with increasing stool volume, with less pH values that can be attributed due to the highest digestibility of dietary fiber and by soluble fiber on diets, with 2.1 and 3.7% values.