Mushroom drying optimization using the Taguchi and Composite desirability methods

BACKGROUND

Oyster mushrooms are perishable and sensitive to heat. Optimization of drying processes is therefore essential to preserve their nutritional and physical qualities.

OBJECTIVE

This study aimed to optimize the drying kinetics and quality attributes of oyster mushrooms using a heat-pump dryer under varying operating conditions.

METHODS

The effects of drying temperatures (40, 50, 60, and 70 °C), air velocity (1, 2, 3, and 4 m.s⁻¹), slice thickness (1, 2, 3, and 4 cm), and pretreatment methods (control, blanching, sonication, and chemical) were evaluated. A Taguchi L₁₆ orthogonal design with triplicate runs was employed, and multi-objective optimization was performed using principal component analysis combined with a composite desirability function. The responses were drying rate (DR), specific moisture evaporation rate (SMER), moisture diffusion coefficient (D_eff), color change (∆E), rehydration ratio (Rh), total flavonoid content (TFC), and total phenolic content (TPhC).

RESULTS

The highest drying rate (7.086 gmin⁻¹) was achieved at 70 °C, 4 m s⁻¹, 1 cm slice thickness, with sonication. Drying temperature contributed 39.2% to the variation in drying rate and air velocity contributed 30.3%. For SMER, temperature and slice thickness had the greatest effects (71% and 14.5%), whereas effective D_eff (1.18 × 10⁻⁸–7.22 × 10⁻⁷ m²s⁻¹) was influenced most by slice thickness (67.8%), temperature (14.5%), and pretreatment (8.9%). Sonication at 60 °C, 2 m·s⁻¹, and 4 cm thickness resulted in the highest Rh (4.67) and ΔE. Based on composite desirability, the optimal drying conditions were 60 °C, 4 m s⁻¹, 4 cm thickness, with sonication pretreatment.

CONCLUSION

This study demonstrates that process optimization enhanced drying efficiency and product quality significantly, with sonication emerging as the most effective pretreatment method. © 2025 Society of Chemical Industry.