Modelling Drying Kinetics of Black Soldier Fly (Hermetia Illucens, L.) Larvae

¹ Instituto Politécnico de Coimbra, Instituto Superior de Engenharia de Coimbra, Rua Pedro Nunes, Quinta da Nora, 3030-199, Coimbra, Portugal
² CERNAS, Instituto Politécnico de Coimbra, Escola Superior Agrária, Bencanta, 3045-601, Coimbra, Portugal
³ Centro de Matemática da Universidade de Coimbra, Apartado 3008, EC Santa Cruz, 3001 - 501, Coimbra, Portugal
⁴ Centro de Estudos de Fenómenos de Transporte, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465, Porto, Portugal

^* Corresponding author: mnazare@isec.pt

Abstract

Hermetia illucens (Black Soldier Fly) larvae (BSFL) have great potential as new protein source for either feed or food use due to the high content of protein and fat. BSFL may be used in different forms including dried with extended shelf life.

Mathematical models describing dehydration kinetics are useful to optimize BSFL drying conditions. A non-stationary 3D diffusion model, given by Fick's Law was used to describe the moisture depletion inside BSFL during drying. The numerical solution of PDE was obtained with COMSOL Multiphysics assuming simple boundary conditions.

Data were obtained in a drying experiment performed with fresh larvae uniformly laid on a metallic grid in a forced air oven at 80 °C. Five randomly larvae were periodically selected and removed for moisture content determination until equilibrium moisture was reached.

A qualitative good agreement between predictions and data was observed corroborating that the main physical phenomena were considered in the mathematical description. A better quantitave description is expected with the improvement of the boundary condition at larvae surface in the model and the upgrading of the three-dimensional geometry used as domain for the numerical resolution.