Characterization of Volatiles in Red- and White-Fleshed Loquat (eriobotrya Japonica) Fruits by Electronic Nose and Headspace Solid-Phase Microextraction with Gas Chromatography-Mass Spectrometry

Aroma differences are generally sensed in white- and red-fleshed loquats. Here, volatile compounds in four white- and three red-fleshed loquat varieties were investigated by headspace solid-phase microextraction and combined analysis of electronic nose (e-nose) and gas chromatography-mass spectrometry (GC-MS). In total, 83 volatile compounds were identified, and 33 were common in all of the cultivars. D-limonene, hexanal, (E)-2-hexenal, octanal and nonanal were the most abundant volatile compounds. beta-cyclocitral and beta-ionone were only detected in red-fleshed varieties. Furthermore, Huayu Seedless 1 (triploid white-fleshed loquats) with low levels of terpenoid compounds detected by GC-MS were clearly differentiated from the other cultivars tested by principal component analysis (PCA), which was consistent with the e-nose results. PCA analysis showed that Huabai 1(white flesh cultivar)had a prominent volatile profile characterized by higher concentrations of C6 aldehydes and alcohols, (E)-2-hexanal, (Z)-3-hexenal and hexanal, (Z)-3-hexenol, (E)-2-hexenol and hexanol. In comparison with red-fleshed loquats, white-fleshed loquats were characterized by high aldehydes content. These volatile compounds served to recognize and classify all of the analysed varieties.