Extrusion cooking of wet mixtures of wheat flour with carrot bagasse in technology of ready-to-eat products

Abstract

The actual challenge for the food industry is the utilization of by-products of fruit and vegetable processing and their use in the production of enriched food products. It allows to use raw materials with a high content of biological active substances more efficiently and rationally. The possibility of using carrot bagasse as an ingredient in the preparation of extruded ready-to-eat product was studied. The wheat meal was used as core ingredient. The influence of the bagasse dosage on the extrusion conditions and the properties of the extrudates samples was studied. It was shown that an increase of the bagasse content more than 20% influenced the quality of the product negatively.The expansion index decreased more than 2 times and the bulk density increased by 40%. The method of additional steam venting from the middle part of the extruder chamber was investigated during the extrusion cooking of mixtures with the bagasse content more than 20% and moisture content 26.5, 28.9 and 34.5%.The indicator of the steam venting was the reduction of pressure in the degassing installation. As a result, the moisture content of the material in the die zone of the extruder chamber decreased. It was shown that additional steam venting during extrusion of high-moisture mixtures led to more severe extrusion conditions. The temperature, die pressure and torgue increased significantly. It imroved the quality of extrudates. Steam venting during extrusion of blends with 26.5 and 28.9% moisture increased expansion index more than 2 times and decreased the bulk density by 21-25%.Extrusion process of a mixture with a moisture content of 34.5% without and with steam venting was unstable and did not allowed to obtain samples of extrudates with acceptable quality. The proposed method for extrusion of high-moisture blend of wheat flour with carrot bagasse can be basis for developing technologies for the production of ready-to-eat extruded products using moist food by-products of fruits and vegetables processing.