Effect of Drying Method on Selected Physical and Functional Properties of Powdered Black Soldier Fly Larvae

Abstract

This research aimed to assay the impact of convective drying (CD) or infrared-convective (IR-CD) drying methods on the physical and techno-functional properties, FTIR spectra, and mathematical modeling of adsorption kinetics of black soldier fly larvae powders. By using convective drying, insect powder exhibited higher water content and water activity but lower hygroscopicity than powder dried with the infrared-convective method. After drying with the convective method, the powder exhibited a significantly lower loose and tapped bulk density and oil holding capacity (OHC). Furthermore, this powder was lighter and more yellow. The FTIR spectrum of the CD-dried powder showed lower absorption at key wavenumbers for the protein (1625 and 1350-1200 cm-1), indicating lower denaturation and less ability to bind water and water vapor. The mathematical modeling of the water vapor adsorption kinetics of insect powders via the second Fick's law for transient diffusion showed that this equation is suitable for adjusting the experimental data based on the high coefficient of determination (0.997-0.999) and the low root mean square (2.50-3.34%). This study revealed that the drying method influences insect powder properties, and the IR-CD method seems better in terms of obtaining better techno-functional properties.