Effect of mixed fatty acid esters prepared from different vegetable oils on the drying rate of 'Thompson seedless' grapes

The efficacy of the dipping oil, made by using mixed fatty acid esters prep ared from alcoholysis of commonly available vegetable oils, during dehydrat ion of grapes to raisins for commercial utility was examined. Commercially, the dipping oil is being imported into the country for making raisins. The mixed fatty acid esters were prepared in the laboratory from five vegetabl e oils separately viz., groundnut, safflower. sunflower, cottonseed, and ri ce bran by the CFTRI processes. These were compared with the imported dippi ng oil and found to be superior. Individual fatty acids viz., ethyl oleate, ethyl palmitate, ethyl stearate and ethyl laurate were also used to prepar e dipping emulsions and mere compared with those, using only potassium carb onate. In another experiment, the different methods of pre treatments viz., lye-dipping, using dipping emulsion prepared from the imported dipping oil s/ethyl oleate/and mixed esters from cottonseed oil were used and compared with that of control in a cabinet tray drier with a batch capacity of 60 kg .