Evaluation of the sensory properties of ready to eat protein-enriched corn-soybean extruded snacks

Abstract

Maize (Zea mays), is among the most widely-cultivated crops in Uganda, but has very minimal protein content. Soybean (Glycine max), has been used extensively blended in various products to enhance their protein content. Extrusion is a short time process in which feed material is cooked by means of temperature, moisture, mechanical shear, and pressure, as it is forced through a die. This study was aimed at developing protein enriched snacks from maize and soy. The effect of the extrusion parameters: barrel temperature (90, 120 and 150o C), feed moisture content (10%, 15% and 20%) and the maize-soybean ratios (0%, 15% and 30% soy content) on the sensory properties (color, taste, aroma, texture /crunchiness and overall acceptability) of the extruded snacks was evaluated through sensory evaluation. The color, aroma and taste scores increased with increase in the soy content of the feed. Color was more pronounced at higher temperatures. High moisture content (>10%) resulted into hard texture of the snacks. The overall acceptability of the samples increased with higher degree of liking of the attributes. The best maize-soybean extrudates were obtained at a barrel temperature of 90o C, 10% moisture content and a mixing ratio of 30 parts of soybean flour to 70 parts of maize flour. There is need to improve the acceptability of the extrudates through use of flavoring. Maize (Zea mays), is among the most widely-cultivated crops in Uganda, but has very minimal protein content. Soybean (Glycine max), has been used extensively blended in various products to enhance their protein content. Extrusion is a short time process in which feed material is cooked by means of temperature, moisture, mechanical shear, and pressure, as it is forced through a die. This study was aimed at developing protein enriched snacks from maize and soy. The effect of the extrusion parameters: barrel temperature (90, 120 and 150o C), feed moisture content (10%, 15% and 20%) and the maize-soybean ratios (0%, 15% and 30% soy content) on the sensory properties (color, taste, aroma, texture /crunchiness and overall acceptability) of the extruded snacks was evaluated through sensory evaluation. The color, aroma and taste scores increased with increase in the soy content of the feed. Color was more pronounced at higher temperatures. High moisture content (>10%) resulted into hard texture of the snacks. The overall acceptability of the samples increased with higher degree of liking of the attributes. The best maize-soybean extrudates were obtained at a barrel temperature of 90o C, 10% moisture content and a mixing ratio of 30 parts of soybean flour to 70 parts of maize flour. There is need to improve the acceptability of the extrudates through use of flavoring.