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Ultrasonic Pre-treatment on Osmotic Dehydration of White Radish
(Raphanus Sativus L.)
Che Wan Muhammad Khir Ridzuan bin Che Wan Rozelah
Supervisor: Dr. Nora Salina Binti Md Salim
Bachelor of Applied Science (Electronics and Instrumentation Physics)
School of Ocean Engineering
White radish (Raphanus sativus L.) is a root crop vegetable with higher moisture
content; which make it more susceptible to deteriorate. Thus, osmotic dehydration is
one of the suitable methods for extending the shelf life. In this work, the influence of
ultrasound pre-treatment prior osmotic dehydration on the mass transfer, shape and
microstructure of white radish were investigated. The white radish dices were
subjected to ultrasonic bath at a frequency of 50 kHz for 10, 20 and 30 min. Osmotic
dehydration process was then carried out by immersing the pre-treated samples in at
different osmotic solutions: 10 % (w/w) NaCl and 10 % (w/w) NaCl with 25 % (w/w)
sucrose at room temperature for a contact period of 0, 30, 60, 90, 120,150 and
180 min. The results show that the mass transfer of pre-treated samples increased
with the increase of ultrasound pre-treatment time. The observation can be confirmed
through the shape changes and microstructural property.
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