Influence of Cultivars and Drying Conditions on Color and Antioxidant Capacity of Lotus Leaves (Nelumbo nucifera Gaertn.)

This research aimed to study the influence of cultivars and drying conditions on color, total phenolic compounds and %DPPH of lotus leaves.  Four cultivars of lotus leaves: East Indian lotus, Hindu lotus, Roseum Plenum and Magnolia lotus were studied.  The lotus leaves were cut into 1*1 cm² and dried in hot air oven at 60, 80 and 100 ^oC until the samples had 3% moisture content.  To reach 3% moisture content, the lotus leaves were dried at 60, 80 and 100 ^oC for 4 hr, 3 hr and 40 min, respectively.  It was found that cultivars and drying conditions had significantly effect on color and antioxidant capacity of lotus leaves.  Drying lotus leaves at 60 ^oC yielded highest L*, a* and b* value in all cultivars.  L* and b* value of Roseum Plenum, Magnolia lotus and Hindu lotus leaves were not significantly different and were higher than East Indian lotus leaves.  East Indian lotus leaves had highest green a* value.  Drying lotus leaves of 100 ^oC yielded highest total phenolic compounds but lower %DPPH radical scavenging capacity in all cultivars.  At 60 ^oC, cultivars had no effect on total phenolic compounds but had significantly effect on %DPPH radical scavenging capacity.  East Indian lotus leaves had the highest %DPPH radical scavenging capacity and Hindu lotus leaves had the lower value.  The result of color and antioxidant capacity showed that drying East Indian lotus leaves at 60 ^oC was the best condition.