Volatile profiles of 47 monovarietal cloudy apple juices from commercial, old, red-fleshed and scab-resistant apple cultivars

Giulia Chitarrini,Karin Brunner,Hildegard Von Lutz,Lidia Lozano,Walter Guerra,Valentina Lazazzara,Peter Robatscher,Flavio Ciesa,Giuseppe Lubes,Josep Valls,Michael Oberhuber,Sara Agnolet

doi:10.1007/s00217-021-03826-7

Abstract

This study provides cultivar-specific metabolic fingerprints of volatile organic compounds in the headspace of cloudy apple juices. Cloudy juices from 47 “true to type” apple cultivars grown under identical agricultural and climatic conditions in South Tyrol, Italy, have been analysed through headspace solid-phase microextraction gas chromatography coupled with high-resolution time-of-flight mass spectrometry (HS–SPME/GC–HRTOF–MS), yielding cultivar-specific volatile organic compound (VOC) profiles. Apple cultivars included 10 old cultivars with local relevance, 18 commercial cultivars, dominating the current international market, 10 scab-resistant and 9 red-fleshed ones. The 28 most abundant VOCs were found in the whole dataset, indicating a remarkable chemodiversity within juices. The main discriminant metabolites were butyl acetate; pentyl acetate; 2-methylbutyl acetate; pentan-1-ol; hexan-1-ol; n-hexanal and (E)-2-hexenal. A principal component analysis (PCA) and a hierarchical cluster analysis (HCA) have not identified a clear separation of the analysed cultivar classes. Nevertheless, a series of scab-resistant and red-fleshed cultivars with VOC profiles similar to established commercial cultivars were identified; these data could help substituting current cultivars with more sustainable ones. On a more general basis, our study supports a knowledge-driven selection of apple cultivars for specific consumer preferences and helps appreciating the biodiversity of apples across old local and more recent (scab-resistant and red-fleshed) cultivars.

Highlights

Apple (Malus × domestica Borkh.) is one of the most important fruit crops worldwide [1]
We used headspace solid-phase microextraction (HS–SPME) combined with gas chromatography high-resolution time-of-flight mass spectrometry (GC–HRTOF–MS) and chemometrics to identify and compare volatile organic compound (VOC) in the headspace of 47 monovarietal cloudy apple juices from commercial, old, red-fleshed and scabresistant apple cultivars produced with standardized protocols
Being aware that the pedoclimatic conditions can influence the aromatic characteristics of the apples more or less strongly we ensured the comparability of VOCs profiles, using cultivars that belonged to the Laimburg collection; they were grown on the same site under the same agricultural and climatic conditions and they were identified using molecular genetic tools

Summary

Introduction

Apple (Malus × domestica Borkh.) is one of the most important fruit crops worldwide [1]. We used headspace solid-phase microextraction (HS–SPME) combined with gas chromatography high-resolution time-of-flight mass spectrometry (GC–HRTOF–MS) and chemometrics to identify and compare VOCs in the headspace of 47 monovarietal cloudy apple juices from commercial, old, red-fleshed and scabresistant apple cultivars produced with standardized protocols.

Results

Conclusion