Physicochemical characterisation and impact of Gryllus bimaculatus addition on gluten-free flour blends

Abstract

Gryllus bimaculatus (field cricket) powder is a prospect in enriching gluten-free food products' protein and mineral contents. However, the technological impacts of replacing common gluten-free cereal flours with G. bimaculatus powder are still incipient. This study aimed to characterise nutritional composition, particle morphology, and particle size distribution of G. bimaculatus powder and the gluten-free flours (maize, rice, finger millet and proso millet). Additionally, it investigated the effects of substituting these gluten-free flours with 5%, 10%, 15% and 20% G. bimaculatus powder on proximate composition, hydration and colour properties. G. bimaculatus powder showed significantly (P ≤ 0.05) high protein (44.8 g/100 g) content and essential minerals such as zinc (208.5 mg/kg) and iron (132.2 mg/kg). Micrographs of G. bimaculatus powder revealed compact and heterogenous particles while the flours' particles varied in sizes, and the starch granules had different shapes, sizes and arrangements. Flour particles exhibited bi-and trimodal size distributions ranging from 1.5 μm to 1100 μm with minor peaks preceding major peaks. Finger millet flour had a greater span of 4.12, while proso millet flour had a lower span of 1.97. Particle size correlated negatively with water absorption capacity (WAC) (r = −0.938) and oil absorption capacity (OAC) (r = −0.955), respectively. G. bimaculatus powder addition significantly increased (P ≤ 0.05) fat, protein and fibre contents, decreased (P ≤ 0.05) nitrogen-free extracts, but had no effect on ash content. Hydration properties differed significantly (P ≤ 0.05) except for WAC in proso millet blends. Samples exhibited significantly higher (P ≤ 0.05) WAC than OAC in exception of G. bimaculatus powder and showed no emulsifying activities. Addition of G. bimaculatus powder significantly (P ≤ 0.05) increased colour differences, reduced redness (a*), yellowness (b*) and lightness. The use of G. bimaculatus powder demonstrates the potential to enhance the nutritional properties and modify the colour and hydration of gluten-free flours in the development of novel gluten-free foods.