Volume No. 4 Issue No.: 1 Page No.: 70-76 July-Sept 2009




Zaved Ahmed Khan*, Priya and Supraja Prasad

Medical Biotechnology Division, School of Biosciences and Technology VIT University, Vellore


Received on : June 24, 2009




Osmodehydration is a novel approach towards preservation and is done by immersing the fruit in an aqueous solution with a greater osmotic pressure. It involves two major processes, one being the outflow of water from the fruit and the other being inflow of solute into the fruit and in this work we have studied the effect of osmodehydration parameters on the quality of lychees. (Litchi chinensis).

Lychees not only help in reduction of obesity( low saturated fat content) and prevention of heart attacks(low cholesterol levels) but are also known for their anti-oxidant properties They are nutritionally very beneficial but the major disadvantage is that they are very expensive and grow seasonally, geographical prevalent and thus their preservation becomes an important issue. Though canned lychees are available in the market, microbes like Clostridium botulinum pose a serious threat of spoilage which has been confirmed in our laboratory. Hence we intend to use osmodehydration as an effective solution for their preservation. Although sun drying has been practiced as a conventional method, this may give rise to problems like release of certain free radical ions which are harmful (carcinogenic) for human consumption and reduction in anti-oxidant levels.

Our work focuses mainly on varying the major parameters like concentration of the osmotic agent (d-fructose) and the temperature at which the process was carried out. The first phase was the removal of water using sugar syrup as an osmotic agent. The second phase of the dehydration was air drying where the moisture content is further reduced. By varying these parameters and monitoring the positive (osmodehydrated) and negative (air dried) controls we can determine the best conditions suitable for longer shelf life and safe consumption of lychees.We also found that by exposing the lychees to UV radiation for 120 seconds extends the shelf life .We will be assessing the effect of osmoregulation on antioxidant activity and its improvement by changing above parameters.


Keywords : Lychees, Osmoregualtion, Food preservation, Antioxidant activity.