Dehydrated Fruits by Freeze Drying Technique

Introduction

Thai government organisation offers technology for fruit dehydration by freeze drying technique. Freeze drying is a process in which water in the sample is frozen at very low temperature (between -20°C and -40°C) and then sublimed under vacuum and low temperature (below -50°C). This technique was applied to produce various kinds of dehydrated fruits, namely jack fruit, rambutan, lychee, longan and durian. To stop the enzymatic reaction, the fruits are initially dripped in the solution of 0.1-0.2% sodium metabisulphite and 0.1% citric acid for 30 minutes. Some types of fruits may also require to go through a blanching process. Then fruits are dried in a freeze dryer under appropriate conditions i.e. temperature, pressure, and time. FInal products produced by this technique are porous and light with reminiscent flavour. They have appearance similar to fresh fruits, especially after reconstitution.

Benefits

The advantage of freeze drying technique compared to other drying techniques are: good physical appearance chemical stability biological activity product recovery and reproducibility

For further information please contact :

Asian and Pacific Centre for Transfer of Technology
APCTT Building
C-2 Qutab Institutional Area
P.O.Box - 4575
New Delhi - 110 016
India
Tel : 91-11-26966509
Fax : 91-11-26856274