Use of Ultrasound as Pretreatment for Dehydration of Melons

Abstract

This work examined the influence of the ultrasonic pretreatment prior to air drying on dehydration of melon (Curcumis melo L.). Ultrasonic pretreatment for air drying of fruits was studied and compared with osmotic dehydration. This study allowed estimate of the effective diffusivity water in the air-drying process for melons submitted to ultrasonic pretreatment. Results show that the water effective diffusivity increases after application of ultrasound causing a reduction of about 25% in the drying. During ultrasonic treatment the melons lost sugar, so such a pretreatment stage can be a practical process to produce dried fruits with lower sugar content. Compared to osmotic dehydration, the use of ultrasonic pretreatment performed better when large amounts of water need to be removed from the fruit, since the combined processing time (pretreatment and air drying) is shorter.

Keywords:

• Curcumis melo L.
• Drying
• Melon
• Optimization
• Osmotic dehydration
• Ultrasound

Notes

^a Conditions: osmotic solution = 55°Brix; osmotic solution to fruit ratio = 4:1; temperature = 65°C.

^a Conditions: osmotic solution = 55°Brix; osmotic solution to fruit ratio = 4:1; temperature = 65°C.