abstract
Drying of cape gooseberry fruits is a slow process because of the low permeability to moisture of the
fruit’s waxy skin. In this work, the effect of chemical pretreatments (sunflower oil/K2CO3 or olive oil/
K2CO3 at 28 C, and NaOH/olive oil at 96 C) and physical pretreatments (blanching) to break down the
waxy surface and accelerate moisture diffusion during drying, was assessed. Drying was carried out at
60 C and 2 m/s air velocity for 10 h. The lowest moisture content (0.27 kg water/kg db), the highest vitamin
C content (0.36 mg/g), and the greatest rehydration capacity (1.89) were obtained in fruits pretreated
with olive oil (9.48%) and K2CO3 (4.74%). However, the greatest changes in color (DE = 15.05) and chroma
(DC = 9.03) were also associated to fruits pretreated with olive oil and K2CO3. The effective diffusivity of
water during drying was 7.37 1011 m2
/s in pretreated samples compared with 6.611011 m2
/s for
untreated samples.
2013