Fingerprinting of Volatile Organic Compounds in Old and Commercial Apple Cultivars by HS-SPME GC/GC-ToF-MS

Flavor is the most important feature consumers use to examine fruit ripeness, and it also has an important influence on taste sensation. Nowadays, more and more consumers pay much attention not only to the appearance but also to the fruit's aroma. Exploiting the potential of headspace solid-phase microextraction (HS-SPME) combined with sensitive two-dimensional gas chromatography and the time-of-flight mass spectrometry (GC/GC-ToF-MS) method within 30 old/traditional cultivars of apples (Malus domestica Borkh) coming from the same germplasm and 7 modern/commercial cultivars, 119 volatile organic compounds (VOCs) were identified. The largest group was esters (53), followed by alcohols (20), aldehydes (17), ketones (10), and acids (10). The richest volatile profile was 'Grochówka', with 61 VOCs present. The results revealed a visible difference based on VOC levels and profiles between the different apple cultivars, as well as visible similarities within the same cultivar coming from different farms. Based on a PCA, the commercial cultivars were separated into 7 clusters, including (1) 'Gala', (2) 'Melrose', (3) 'Red Prince', (4) 'Lobo', (5) 'Ligol', and (6) 'Szampion'. The results of this study indicate that the profile of volatile compounds may be a useful tool for distinguishing between commercial and old apple cultivars, as well as for the varietal classification of apples from different locations. The developed method can also be used to identify other fruit varieties and origins based on their VOC composition. This may prove to be particularly valuable in the case of establishing a Protected Designation of Origin or Protected Geographical Indication.