Effect of replacing gluten-free cereal flours with Gryllus bimaculatus powder on pasting and microstructural properties

Gryllus bimaculatus powder can be a sustainable source of animal protein and is a suitable ingredient for enriching gluten-free products. Enriching gluten-free flours with edible insect powder can impact the viscometric behavior of blends and should be considered during formulation. This study explored the effects of substituting rice, maize, finger millet and proso millet flours with 5%, 10%, 15% and 20% G. bimaculatus powder on the pasting and structural properties of the resulting blends. The pasting parameters differed significantly (P ≤ 0.05) except for peak time in the proso millet blends. The pasting viscosity decreased with the addition of G. bimaculatus powder. The average peak viscosities decrease was in the order of rice (546.40 mPa*s) and then finger millet, maize and proso millet (224.40 mPa*s) blends, with greater reductions at 5% and 10% substitution. The positive setback and breakdown viscosities were greater for proso millet than for the rice, finger millet and maize blends: the latter two formed heat-stable pastes suitable for porridge formulation. The average final viscosity reductions were in the order of rice (1045.00 mPa*s), maize, proso millet and finger millet (315.75 mPa*s) blends. G. bimaculatus powder inclusion decreased the peak time but increased the pasting temperature. Cryo-scanning electron micrographs revealed a uniform dense network of clustered structures in flour pastes that gradually degenerated into discontinuous and irregular structures upon adding G. bimaculatus powder. Thus, incorporating 15-20% G. bimaculatus powder with finger millet and maize flour could enhance the development of stable low-viscosity products such as complementary foods correlated with sensory and textural properties.