Drying of Californian red worms (CRW) (Eisenia foetida) was optimized using the refractance window (RW) method. Response surface methodology was used to evaluate the effects of drying temperature (65–85 °C) and mass per unit area (W/A) (0.256–0.367 g/cm2) g/cm2) on the response variables related to the meal’s protein quality and drying parameters. The response variables were digestibility (D), sulfhydryl bonds (SH), protein digestibility-corrected amino acid score (PDCAAS), final moisture content (FMC), and the water effective diffusion coefficient (Deff). The results showed that as temperature increases, Deff also increases, while FMC decreases. Conversely, as the W/A ratio increases, SH increases, FMC increases, and Deff decreases. Furthermore, the optimization of the obtained models yielded values for water temperature (79.9 °C) and W/A (0.367 g/cm2), as well as predicted values for the response variables D (96.87%), FMC (4.12%), Deff (1.041 × 10−10 m2/s), SH (19.11 μmol/g protein), and PDCAAS (0.459); with a desirability of 0.734. The experimental values obtained for optimal conditions were D: 97.14%, FMC: 6.8%, Deff: 6. × 10−11 m2/s, SH: 14.84 μmol/g protein, and PDCAAS: 0.780. This drying method proved optimal and efficient for dehydrating Californian red worm meat, as it preserves the protein quality of the worm meal while ensuring appropriate drying conditions.
Sánchez-Uribe et al. (Tue,) studied this question.