Desenvolvimento de extrudado para cereal matinal enriquecido com fruto-oligossacarídeos

Abstract

The use of food as a vehicle for promoting welfare, health and, at the same time used as reducing the risk of some diseases, has stimulated the search for diferents natural compounds enabling the innovation of foods and creating new market niches. This work aimed at developing an extruded breakfast cereal, enriched from replacing part of corn meal by fructooligosaccharides. Extruded samples were prepared by thermoplastic extrusion using mixtures of fructooligosaccharides with cornmeal in proportions of 0:100, 2:98, 5:95, 8:92 and 10:90. The samples were extruded with moisture content of 25, 27, 30, 33 and 35% in a Brabender single screw extruder with barrel temperature of second heating zone of 90.0ºC and third heating zone ranging of 60,0, 68.1, 80.0, 91.9 e 100.0 °C. The extruder was equiped with a flat die of 1 mm wide and screw compress ratiun of 3:1 running at 120 RPM whit the solid feed rate set at 20 RPM. The samples were characterized by chemical composition, microbiological evaluation for molds and yeasts and coliforms at 45 º C, HPLC of nistose and kestose content determination after processing, intake rate of complex sugars / simple sugars due the addition of FOS, absolute density, apparent density, water solubility index (WSI), water absorption index (IAA), paste viscosity by rapid visco-analiser (RVA), texture by instrumental method, bowl time and extrusion out put. We obtained a product < 10 UFC/gfor molds and yeasts and < 0,3 NMP/g para coliforms at 45ºC at central point level. The results of chemical composition were similar to the literature and the loss of FOS by the extrusion process was very low. The relative and absolut densities of the baked products were lower than the raw products indicated by a degree of expansion. All treatments presented similar viscositiy curve shape and viscosite values analyses have showed that the shear had small extent. The IAA values showed that FOS had a negative effect on this parameter wich corroborated with the good results obtained in the bowl time index analysis. In fact, the fiber was significantly effective in producing a product with low tendency of soggy and sticky when soaked in liquid. FOS was also effective in decreasing the hardness of the products, which indicates the use of this kind of fiber for formulating blends with high content of insoluble fraction which tend to increase the hardness of the product.