Optimization of Osmotic Dehydration of Kiwifruit

Abstract

Mass transfer rates were quantitatively investigated during osmotic dehydration of kiwifruit slices using response surface methodology with the sucrose concentration (20–80%, w/w), temperature of sucrose solution (15–75°C), osmotic time (60–420 min), and slice thickness (2–10 mm) as the independent process variables. Quadratic regression equations are obtained to describe the effects of independent process variables on the water loss (WL), sucrose gain (SG), and ascorbic acid loss (AAL). It was found that all factors had significant effect on the WL during osmotic dehydration of kiwifruit. Effects of temperature, time, and slice thickness were more pronounced on SG than the effect of concentration of sucrose solution. The osmotic solution temperature was the most significant factor affecting the AAL, followed by slice thickness and duration of treatment. The optimal conditions for osmotic dehydration were: 60% sucrose concentration, 30–40°C osmotic temperature, 150 min osmotic time, and 8 mm slice thickness.

Keywords:

• Osmotic dehydration
• Sucrose
• Response surface methodology
• Ascorbic acid

ACKNOWLEDGMENTS

The authors thank leaders and staffs of Haitong Food Group Co., Ltd, Ningbo, Zhejiang, China, for their practical assistance in the project. The authors thank the Chinese Ministry of Science and Technology for financial support under Contract No. 04EFN213310125.

Notes

***, **, *: Coefficient significant at p ≤ 1%, p ≤ 5%, p ≤ 10%, respectively.