Elaboração de produtos de milho enriquecidos com grãos e torta semi-desengordurada de gergelim por extrusão termoplástica

Abstract

It has grown the search for more nutritious food of low cost and with consumer’s appealing. The sesame seeds present great contribution to human food because they have high protein content (18.6%), oil (49.1%), fiber (6.3%) and minerals in which calcium stands out (1, 16%). It is easy to grow and can be considered of great importance for the Brazilian economy, because it shows fast agricultural production cycle, and also drought tolerant which is indicated crop to the drought region of the Brazilian Northeast. The thermoplastic extrusion process due to its versatility, continuously and high productivity can also provide excellent mixture of ingredients, therefore can be successfully applied on the mixture of cereals and sesame seeds enabling the increase of sesame crop and consumption. The objective of this project was to develop extruded products made from sesame and maize in order to increase the value added and consumption of sesame. Whole sesame seed and semi defatted sesame cake in mixture with maize grits were used to develop expanded extrudate products and also the pre-gelatinized flours. Central composite design of second order and the mathematical model response surface methodology were used as statistical tools analyses. The effect of temperature of the third (die) heating zone of a lab size extruder single screw extruder Brabender (Duisburg, Germany) and the sesame content were studied as well as the screw speed and semi defatted sesame cake content of the process carried out on a commercial size single screw extruder RX50 Inbramaq (Ribeirão Preto, SP, Brazil). It was observed that both the addition of sesame seeds and sesame cake reduced the expansion of direct expanded extrudates, although it did not influence much the crispness. Compared to similar extrudate commercial products, the extrudates with the highest sesame cake addition (20%) presented the same instrumental textural readings: frequency of ruptures (0.25 mm-1) and average specific structural force (0.06 N) showing the same crispness level of the commercial extrudate. Non trained sensorial panel results also demonstrate that high levels of sesame seeds and semi defatted sesame cake also had good consumer acceptance and intention of purchase confirming the instrument textural analysis. The flours obtained by milling of the extrudates produced in the commercial size extruder presented index of water solubility (17, 87%) value similar to the literature leading to a conclusion that those mix flours of sesame and maize can be considered pre-gelatinized indicated to soup of easy preparation. The processes and products obtained can provide technological alternatives for increase sesame consumption that associated with cereals products of functional relevance potential can be obtained.