Abstract:
Passion fruit, a flowering tropical vine that grows in warm climate has
recently gained a lot of attention because of its rich source of powerful antioxidants
and healthful nutrition profile. Due to its perishable nature, the need for its
processing is also increasing. For this purpose several non-thermal and thermal
techniques are gaining attention all over the world. One among them is Ohmic
heating. Ohmic heating with its many advantages, is a volumetric heating
mechanism, where food is heated by its electrical resistance. in order to preserve
passion fruit pulp with higher retention of its nutritional value, ohmic heating was
applied using an ohmic heating system consisting of ohmic heating
chamber, electrodes, variable transformer and control panel. The effect of ohmic
heating parameters – voltage , temperature and holding time on different
physicochemical properties of passion fruit pulp was also studied and the optimal
condition for ohmic heating treatment of passion fruit pulp with minimal losses was
found. Also the microbial population of the optimized sample was determined.
From the results obtained it was concluded that the increase in ohmic heating
parameters has caused an decrease in ascorbic acid,L* and b* values of passion
fruit pulp while TSS and a* values of the pulp was found to be increasing. The
ttrable acidity of the pulp was not much affected by ohmic heating. By analyzing the
results a voltage of 185.34 V, process temperature of 60.26°C and holding time of
2.32 min was found to be the optimal condition for ohmic heating treatment of
passion fruit pulp The microbial population was found to be significantly low in
treated sample. So by using the optimal conditions, ohmic heating can be
successfully used for preservation of passion fruit pulp with minimum losses.
