The Effect of Feed Moisture and Barrel Temperature on the Essential AminoAcids Profile of Sorghum Malt and Bambara Groundnut Based Extrudates

摘要

Malnutrition is prevalent and serious problem in Africa especially where most people are ravaged and displaced by war especially in northern Nigeria by the activities of the terrorists Boko Haram. Sorghum malt and bambara groundnut flour were processed to produce an extruded product using a twin screw co-rotating intermeshed extruder. The formulations were extruded at 100°C, 120°C and 130°C and feed moisture contents of 20%, 25% and 30% respectively. This work has therefore attempted to investigate the effect of feed moisture and barrel temperature on the retention of essential amino acids in the extrudates. Extrusion was used to obtain best extrusion conditions to develop a protein-enriched extruded product with desirable physio-chemical and sensory properties. The results showed different physical and chemical properties of the extrudates compared to those of the raw materials used. The extrusion of Sorghum malt and Bambara groundnut blend gave a good complement in terms of the essential amino acids but was faced with the challenge of depletion of the amino acids resulting from maillard reaction probably. Extrusion of foods in the presence of reducing sugars has been found to have negative effect on the quality and quantity of the essential amino acids due to maillard reaction. The results showed that the mean observed values for lysine ranged from 3.62 g/100 g to 4.51 g/100 g, while methionine has the values from 1.47 g/100 g to 2.68 g/100 g. The values for reducing sugars ranged from 222.16 mg/100 g to 453.51 mg/100 g in glucose to 680.70 mg/100 g to 835.70 mg/100 g in maltose. ANOVA was adapted for the statistical analyses. The values showed significant difference at p ≥ 0.01. The values decreased with increased barrel temperature, while increase in feed moisture increased the reducing sugar and essential amino acid contents. The essential amino acid content of the extrudates met the FAO/WHO (1973) recommended pattern for supplementary foods. This is the first attempt to produce protein enriched sorghum malt and bambara groundnut extruded product with millet and beans that can be included in a child’s meal as a breakfast cereal or a snack to fight protein malnutrition.