Macrotermes subhylanus flour inclusion in biscuits: effects on nutritional, sensorial and microbial characteristics

Abstract

As the world’s population expands, edible insects have been proposed as a food source that might address issues related to nutrition, health, the environment, and the economy. This study aimed to create a novel biscuit by adding Macrotermes subhylanus (M. Subhylanus) flour to wheat flour in various concentrations (5,10, 15 and 20 %). The moisture content of the insect composite flours varied between 6.83 % and 7.76 %, whereas the moisture content of the biscuits ranged from 2.86 % to 7.90 %. A significant difference (p < 0.05) was noted in the protein content of both the composite flours and biscuits as the concentration of insect flour increased, with values ranging from 15.03 % to 21.52 % for the flours and 17.38 % to 20.63 % for the biscuits. The lightness (L*) of the composite flours significantly decreased (p < 0.05) with higher additions of edible insect flour, whereas the redness (a*) and yellowness (b*) attributes did not show any statistical differences (p > 0.05). The biscuits were generally darker than the composite flours, as indicated by substantially lower L* values. The water activity of the biscuits was between 0.44 and 0.67. Sensory evaluation revealed that the substitution level (up to 15 %) is ideal for preparing acceptable insect-based biscuits. The panellist perceived no significant differences (p > 0.05) in terms of the texture between the insect-enriched biscuits and the control, except for MZ-20. The absence of pathogenic microogranisms in all baked biscuits containing edible insect flour highlights the effectiveness of heat treatment, ensuring that the biscuits meet microbiological safety guidelines. Additionally, Macrotermes subhylanus flour shows promise as a novel functional ingredient for the food industry.