Abstract:

The applicability of empirical solid uptake predictive models was assessed during acoustic/pulsed-vacuum osmodehydration, and the effect of vacuum or ultrasound on solid uptake kinetics was also investigated. Apple cylinders were submerged in a 60% (W/W) syrup under shaking (55 r/min), pulsed vacuum (13 MPa vacuum for 5 min + atmospheric pressure for 5 min + same vacuum for 5 min, then atmospheric pressure), or ultrasound treatment (50/60 Hz) for 3 h. The R2, χ2, RMSE and E values of seven selected models were compared, Two-term model presented the best fitting for solids uptake. The solute diffusivity ranged from 5.72 × 10-11 to 9.25 × 10-11 m2/s. Pulsed vacuum led to the greatest amount of solids gain (3.02%) and the highest diffusivity (9.25 × 10-11 m2/s).

Key words: apple, model, osmotic dehydration, pulsed vacuum, solids uptake, ultrasound