Ethylene Treatment Minimally Affects Star Ruby Grapefruit Bioactive Compounds and Their Radical Scavenging Activity
Monday, August 2, 2010
Springs F & G
In recent years bioactive compounds have shown potential as anti inflammatory, anticarcinogenic and cholesterol lowering agents. Citrus fruits contain bioactive compounds such as triterpenoids, flavonoids, phenolics, folic acid, furocoumarins and vitamins. Early season mature citrus fruits are commercially treated with ethylene to improve peel color and marketability. In the present study, investigations were conducted to understand the effect of ethylene on Star ruby bioactive compounds and their radical scavenging activity. Star ruby fruits were degreened in commercial packing shed and later stored under simulated market conditions for 5 weeks. Ethylene degreening enhanced the peel color of degreened fruits but had no remarkable effect on internal fruit color. Bioactive compounds from non-degreened and degreened fruits were quantified by HPLC. Nomilin content in degreened fruits was higher than non degreened fruits after 35 days of storage. No significant effect of ethylene treatment was observed on carotenoids and ascorbic acid content. Radical scavenging activity of Star ruby fractions were determined using 1,1-diphenyl-2-picryl hydrazyl (DPPH) method and results were expressed as ascorbic acid equivalents. Radical scavenging activity of degreened fruits was higher after 0, 7 and 14 days of storage as compared to non-degreened fruits. Total phenolics in the Star ruby fractions were determined by Folin-Ciocalteu method and results were expressed as catechin equivalents. No difference was observed in total phenolics content in both treatments and there was gradual increase up to 35 days. Therefore it may be possible to use degreening to improve fruit appearance and aesthetic value while minimally affecting bioactive compounds present in Star ruby grapefruit. To best of our knowledge this is first report on variation of bioactive compounds and their radical scavenging activity in edible portion of grapefruit after ethylene treatment.