Development and microbiological load of composite flours from locusts, grasshoppers and malted finger millet

Abstract

This study attempted the processing and inclusion of insects into a local staple food to endear them to the population. Mature desert locusts (Schistocerca gregaria) and migratory grasshoppers (Acanthacris ruficornis) reared at Egerton University were dried and ground into powder then used to develop composite flours with malted finger millet flour. Proximate analysis and protein digestibility tests of the composite flours were done and their microbial loads (total viable counts, TVC; coliforms; Lactic acid bacteria, LAB; Yeasts and molds) were evaluated. The addition of locust and grasshopper flour increased the protein and fat contents of finger millet flour from 9.20 to between 13.60 and 27.30% and from 1.40 to 3.30–11.40%, respectively. Protein digestibility of the finger millet was improved by malting (from 71.50 to 91.50%) while that of the insect flours was high (approximately 90.00%). The microbial loads in individual products and in composite flours ranged between 106–108 cfu/g for TVC, 105–108 cfu/g for coliforms, 104–107 cfu/g for LAB, and 1.7–2.5 × 107 for yeasts and molds. Our study indicates that locusts and grasshoppers could be incorporated into existing staple foods to generate highly nutritious products that could be recommended to fight malnutrition.