INFLUENCES OF GRAFTING ON AROMATIC COMPOUNDS IN MUSKMELON BY SOLID PHASE MICROEXTRACTION WITH GC-MS

There has been an increase in popularity of grafting technique on muskmelon in agricultural production because grafting of melon increased its disease resistance to fusarium wilt, but melon's (Cucumis melo L.) quality has been more serious inferior than its own-rooted melon. The volatiles substance plays an important role in melon fruit quality. We have found very little reports in literature for melon grafting varieties and using solid-phase microextraction (SPME). The objective of this experiment was to identify volatile and semivolatile compounds in two melon cultivars 'Lu135' and 'Lu7475', using solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS). Fully ripe melon was squeezed through miracloth to produce rapid juice extracts for immediate headspace SPME GC-MS. One hundred forty two volatile compounds were separated in ripe muskmelon, they consisted of 56 esters, 27 alcohols, 3 aldehydes, 17 ketones, 21 alkenes and 18 other substances. Among these compounds, types of esters and alcohols were the important aroma components accounting for over 74.75-93.46% of total peak area. The most abundant compounds in two cultivars were acetic acid, phenylmethyl ester (21.65-36.43%), acetic acid, hexyl ester (6.05-12.95%), ethyl acetate (2.89-9.94%), 1-butanol, 2-methyl-, acetate (5.84-7.82%). The total aromatic compounds and characteristic aromatic esters contents decreased in grafted melons than the own-rooted melon. The delightful fruit aroma in grafting melon was lower and thinner in comparison to own-rooted. Meanwhile, the aroma components of melon were altered because of grafting in adopting of melon. However, the effect of grafting on aroma components was different between two varieties. The total esters content and category in 'Lu135' was obviously lower in grafting melons than own-rooted and it had little chance on 'Lu7475'.