Development of a high protein weaning food by extrusion cooking using peanuts, maize and soybeans

Abstract

A standardized extrusion cooking process was developed for production of a high protein weaning food based on peanuts, maize and soybeans. Major factors evaluated included the effects of blend formulation, extrusion temperature and feed moisture content on ease of extrusion and product quality characteristics. Results showed bulk density and hardness increased while expansion index decreased with increase in feed moisture content. At a fixed range of feed moisture content, product bulk density and firmness decreased while expansion index increased with increasing extrusion temperature. For ease of extrusion and best product quality in terms of sensory attributes and cooking properties, the following extrusion parameters were established for a blend formulation of 75% maize, 10% peanut and 15% soybean: feed particle size of 300.400 um extruded using a screw speed of 500 rpm, with a feed rate of 4.6 kg/min, feed moisture content of 16.18%, and extrusion temperature of 100 .C.105 .C. Pairwise comparison of the sensory attributes of porridges prepared from milled samples of the weaning foods showed significant differences between extruded products and existing traditional counterparts, with very high scores for all sensory attributes of the extruded products, especially extruded raw (nonroasted) blend samples. In the Home-Use-Test, at least 92% of respondents in two out of the three major ecological zones of Ghana placed overall sensory and functional characteristics of extruded raw blend samples as `highly acceptable`. About 7% of respondents scored sensory and functional quality attributes as `acceptable`