[Effects of different color paper bags on volatile constituents of Kyoho grape berries]

Taking'Kyoho' as the test material, the effect of white, green, red and blue bags on volatile compounds in mature grape berries was explored in this study. The results indicated that bags with different colors could create special light conditions, which resulted in the difference of volatile compounds in grape berries. A total of 37, 38, 32, 34 kinds of volatile compounds which included esters, aldehydes, alcohols, ketones, terpenes and aromatic compounds, were detected in 'Kyoho' berries covered with the white, green, red and blue bags respectively, and 33 in the control. Compared with the control, the contents of ethyl acetate, ethyl hexanoate and some other esters decreased, while hexanal, E-2-hexenal and decanal increased in berries with white bags, the contents of the major common compounds, except ethyl 3-hexenoate, ethyl (E)-hex-2-enoate, ethyl 3-hydroxybutyrate, E-2-hexenal, (E,E)-2,4-hexadienal, decanal, and phenethyl alcohol, decreased in berries with green bags, the contents of ethyl acetate, ethyl hexanoate and hexanal, E-2-hexenal decreased in berries with red bags, the contents of ethyl acetate, ethyl hexanoate and some other esters changed slightly in berries with blue bags, except for the increase of hexanal and E-2-hexenal. For those characteristic compounds, the kinds of alcohols in berries covered with bags decreased while the kinds of terpenes and aromatic compounds increased. In general, the fruits with the blue bags had the highest volatile esters, and those with the white bags had high volatile esters and aldehydes, while those with the green and red bags had low aromatic compounds.