Early identification and monitoring of soft rot contamination in postharvest kiwifruit based on volatile fingerprints using headspace-gas chromatography-ion mobility spectrometry

Soft rot is one of the most devastating fungal diseases occurring in kiwifruit during postharvest storage. Whereas, the approaches for rapid, precise and non-destructive testing of early soft rot contamination are still scarce. This study successfully employed headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) to evaluate volatile organic compounds (VOCs) of soft rot kiwifruit contaminated with three pathogenic fungi including B. dothidea, Diaporthe spp., A. alternata. A total of 88, 106, 110 and 99 VOCs were detected in non-infected, B. dothidea, Diaporthe spp., A. alternata-infected kiwifruit, respectively. Specific fingerprints were established with 15, 26 and 11 characteristic VOCs emitted by three pathogenic fungi invading kiwifruit and not present in non-infected kiwifruit, accomplishing effective discrimination between healthy and disease kiwifruit. Additionally, alternative potential volatile biomarkers for soft rot kiwifruit were screened, such as α-terpinene, α-terpinolene, 3-p-menthanol, 3-hepten-2-one, ethyl 2-methylbutanoate, etc. These findings promised non-destructive and timely monitoring for disease occurrence during kiwifruit postharvest.