Abstract:

【Objective】Comparison on ripening characteristics, main aroma compounds and aroma-related enzymes activities between two cultivars of oriental sweet melons were conducted.【Method】Gas chromatograph and oxygen electrode method were used to detect ethylene production and respiration rate, respectively. Varieties and content of aroma compounds were measured by gas chromatograph-mass spectrometer(GC-MS), whilst aroma-related enzymes activities were also determined.【Result】 Climacterics of ethylene and respiration of ‘Caihong7’ were 3 days earlier than ‘Japanese Tianbao’. The soluble solids contents of mature ‘Japanese Tianbao’ were significantly higher than that of ‘Caihong7’. The contents of alcohols and aldehydes were higher of ripening ‘Japanese Tianbao’ were higher than that of ‘Caihong7’ markedly, while the differences on content of total aroma volatiles and esters were not significant. The content of total and acetate esters reached maximum value on day 33 and 35 after anthesis in ‘Caihong7’ and ‘Japanese Tianbao’, respectively. Activities of LOX in flesh and peel of ‘Japanese Tianbao’ were significantly higher than in ‘Caihong7’, whereas AAT activities followed the opposite trend and no significant differences in ADH activities were observed in both cultivars. The content of aroma compounds and enzyme activities were higher in peel than in flesh of both cultivars. 【Conclusion】Higher contents of alcohols and aldehydes in mature ‘Japanese Tianbao’ considered to be important contributors to its cucumber-like flavor. The different components proportion of aroma compounds might be the reason for causing different types of fragrance between both cultivars. LOX, ADH and AAT had interaction effects on fragrance types.

Key words: oriental sweet melon, ethylene, respiration rate, aromatic compounds, aroma-related enzymes