| dc.description.abstract | This study aimed to investigate the changes in the chemical and physical
properties of pumpkin dried at 70°C after undergoing pretreatment with sucrose
and erythritol solutions at concentrations of 30% and 50%, with and without the
assistance of ultrasound. The water loss (WL) and solid gain (SG) during
pretreatment were examined to assess the effectiveness of the process. The
highest water loss was observed in samples treated with ultrasound-assisted
osmotic dehydration (USOD) in a 50% sucrose solution, while samples treated
with a 30% erythritol solution (30E) exhibited the highest solid gain. Furthermore,
the experimental data obtained during the drying process were fitted to four
theoretical models to predict the drying kinetics of the pumpkin. Among these
models, the Midilli et al.'s model showed the best fit to describe the process. The
drying time of the USOD 30E sample was the shortest, at 176 minutes,
representing a decrease of 50.28% compared to the control sample to reach a
final moisture content of 20%. Significant differences in the chemical and physical
properties of the pumpkin were observed after pretreatment with osmotic
solutions, with and without ultrasound. Regarding carotenoid content and DPPH
(2,2-diphenyl-1-picrylhydrazyl) activity, the USOD samples showed no significant
difference from the untreated samples (p > 0.05). However, the control samples
had the highest total phenolic content. Additionally, the OD and USOD samples
exhibited lower hardness, lower shrinkage ratio, brighter color, and higher overall
organoleptic scores compared to the non-pretreated samples. The findings of this
study demonstrated that OD and USOD treatments had the potential to conserve
energy, reduce drying time, and potentially improve the quality of fruits after
drying. | en_US |
