Preservation of fruits: a study on apples based on monitoring VOCs by the novel Proton Transfer Mass Spectrometry method (PTR-MS)

Volatile Organic Compounds (VOCs) were successfully used as a non- destructive method to monitor the state and quality of fruits and vegetables. In particular, Proton Transfer Reaction Mass Spectrometry (PTR-MS) can be nicely used to qualify post-harvest preservation. This is in fact a very sensitive and real time technique that allows the monitoring of a large number of organic volatile compounds down to a few pptv (part per trillion in volume) sensitivity. Using such an apparatus, we have investigated the preservation of two varieties of apples (‘Renetta Canada’ and ‘Golden Delicious’) under different conditions and treatments over the whole storage period and during their shelf-life. The emission of VOCs was clearly influenced by the storage conditions and treatmentsand correlated to the final product state and quality. Principal Component statistical Analysis (PCA) confirms the ability of PTR-MS to be a reliable and very sensitive way to discriminate the different procedures and conservation receipts by detecting organic volatile compounds. The method is envisaged as being very promising to optimize fruit quality during the whole chain of storage and marketing.