Nutritional quality and storage stability of extruded weaning foods based on peanut, maize and soybean

Abstract

Samples of extruded high protein weaning foods were produced using blends of peanuts, maize and soybean to achieve the desired level of protein. The extruded products, based on a raw and a preroasteds mix of ingredients, were developed and characterized in terms of the hot paste viscosity characteristics, chemical and nutritional quality, amino acid composition, and storage stability. A comparative evaluation of the extruded products was undertaken in relation to two similar existing products: the traditional roasted maize flour weaning food, and the commercial version. In general, the extruded products were found to have better nutritional quality as indicated by the high protein content of 16.5–18.7% and quality, and excellent rat growth response. For both types of extruded weaning foods developed, between sixty- and one hundred-fold increases in mean weight gain of test rats were recorded over those eating the traditional sample. Correspondingly, the PER values which were between 2.3 and 2.5, were almost thrice the values obtained for the existing products. Significantly higher feed efficiency ratios were also obtained for the extruded products. Hematological data of test animals showed normal values for white blood cell (WBC) count, red blood cell (RBC) count, hemoglobin (Hb) levels and packed cell volume (PCV) for all the weaning foods studied, except the existing traditional roasted maize flour. In terms of storage stability of the extruded products, predicted shelf life periods of 7.8–10.4 months were obtained for the extruded raw blend, and 5.6–7.1 months for the extruded preroasted blend when stored at the average ambient temperature of about 30 ◦C in Ghana. In general, the preroasting treatment was found to reduce the quality characteristics of the extruded product