Thin-layer drying characteristics of black solo garlic: Mathematical and ANN modelling, diffusivity, and antioxidant enhancement

Abstract

Drying is a critical step in processing black solo garlic to enhance its stability and broaden its applications. This study investigated the effects of drying temperature (50–70 °C) on the convective oven drying kinetics, energy consumption, physicochemical properties, and antioxidant activity of black solo garlic slices. Drying behaviour, effective moisture diffusivity, and activation energy were evaluated. Several thin-layer models and an artificial neural network (ANN) were applied to describe the drying kinetics. Increasing drying temperature increased the drying rate, reduced drying time and energy consumption. The effective moisture diffusivity ranged from 4.16 × 10 −10 to 7.45 × 10 −10  m 2  s −1 , with an activation energy of 27.07 kJ mol −1 . Drying occurred entirely in the falling-rate period, indicating internal moisture diffusion as the dominant mechanism. The ANN model demonstrated excellent predictive performance comparable to that of the thin-layer models ( R 2 > 0.99; RMSE < 0.02). Higher drying temperatures promoted melanoidin formation and increased antioxidant activity (6.91–9.13 mg AAE/g db) while preserving phenolic content, although rehydration capacity decreased. Among the investigated conditions, 70 °C provided the best overall balance for the production of dried black solo garlic as a functional food ingredient. These findings demonstrate the potential of combining thin-layer mathematical modelling and ANN to optimise industrial drying processes for black solo garlic.