Mushroom drying optimization using the Taguchi and Composite desirability methods

Abstract

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 L<inf>16</inf> 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<inf>eff</inf>), 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<inf>eff</inf> (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.