The present work was designed to compare the vitamin C (ascorbic acid, AsA) content of pulp, peel, and juice of 64 apple cultivars. These cultivars were carefully identified as 'true to type' by molecular genetic tools, grown in the same site under identical conditions and processed by a standardized protocol. Twenty-one of them, accounting for more than 95% of the apple production of South Tyrol, were chosen to represent the current market, 16 were old or local cultivars formerly grown in the area, and 27 were new cultivars, including 15 with scab resistance and 12 with red flesh fruit. For the determination of the AsA content, a new High-Performance Liquid Chromatography with Diode-Array Detection method was developed and validated. While old cultivars stood out for their high AsA content in pulp and peel, the red-fleshed cultivars are the ones maintaining most of their AsA content during processing. Our data thus suggest a potential for old and red-fleshed cultivars for healthy juices or further processed food components.

Volatile organic compounds (VOCs) are chemical species that play an important role in determining the characteristic aroma and flavor of fruits. Apple (Malus × domestica Borkh.) cultivars differ in their aroma and composition of VOCs. To determine varietal differences in the aroma profiles, VOCs emitted by 7 modern and 35 old apple cultivars were analyzed using Proton Transfer Reaction Mass Spectrometry (PTR-MS). PTR-MS is a rapid, reproducible, and non-destructive spectrometric technique for VOC analysis of single fruits, developed for direct injection analysis. In the present study, we analyzed the differences in the emission of VOCs from single fruits at harvest and after a storage period of 60±10 days, followed by 3 d of shelf life. Our results show that VOC profile differences among apple cultivars were more pronounced after storage than at harvest. Furthermore, chemodiversity was higher in old cultivars compared to modern cultivars, probably due to their greater genetic variability. Our data highlight the importance of storage and shelf life are crucial for the development of the typical aroma and flavor of several apple cultivars. The validity of the method is demonstrated by comparison of two different harvest years.

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