THE DEHYDRATION OF GARLIC 2. THE EFFECTS OF PRETREATMENTS ON DRYING KINETICS

The kinetics of drying of pretreated garlic slices of thickness 1.5 - 5.0 mm were determined at between 40 and 60°C using an air flow rate of 2.5 m/s. Pretreatmenl consisted in immersion of the slices in water or solutions of K₂CO₃, K₂CO₃ with olive oil, Na₂S₂O₅ or NaOH, at 25°C for 60 or ISO s. The effects of each pretreatmenl on the drying kinetics and the quality of the dried product were evaluated, in the latter case by determining its rehydration ratio. Pretreatment with water or the Na₂S₂O₅ solution gave good results regardless of the thickness of the garlic slices, whereas pretreatment with a dilute NaOH solution gave good resuhs for thin slices (≤2.5 mm). The experimental kinetic data were satisfactorily fitted by a difiusional kinetic model developed in Part 1 of this work.