Discrimination of four different postharvest treatments of ‘Red Delicious’ apples based on their volatile organic compound (VOC) emissions during shelf-life measured by proton transfer reaction mass spectrometry (PTR-MS)

• Published in: Postharvest biology and technology 2013-12, Vol.86, p.329-336
• Main Authors: Ciesa, Flavio, Dalla Via, Josef, Wisthaler, Armin, Zanella, Angelo, Guerra, Walter, Mikoviny, Tomas, Märk, Tilmann D., Oberhuber, Michael
• Format: Article
• Language: English
• Subjects: Apple (Malus × domestica Borkh.); Biological and medical sciences; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Malus; PTR-MS; Red Delicious; Shelf-life; Storage techniques; Volatile organic compounds
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/j.postharvbio.2013.06.036

•PTR-MS was used to monitor VOCs in the headspace of ‘Red Delicious’ apples during ripening under shelf-life conditions and after storage for seven months.•Four different storage techniques (ULO, RLOS, DCA-CF, 1-MCP+ULO) were used.•We were able to follow quality-critical aroma compounds in the headspace of apples in real time.•Non-destructive measurement such as PTR-MS are important technologies supporting the development of chemical sensors for quality control in postharvest science (e-nose). Storage methods extend the postharvest life of apples from weeks to up to one year; however, these methods also alter the production of volatile organic compounds (VOCs), which amongst others, are important for aroma attributes. While the impact of storage on particular aroma components has been established, high throughput methods for determining the storage history during shelf-life are elusive. Here we show the potential of proton transfer reaction-mass spectrometry (PTR-MS), an MS-based metabolic fingerprinting technique, for characterizing fruit in the postharvest chain. The VOC fingerprint of apples (Malus×domestica Borkh. ‘Red Delicious’) was analyzed by PTR-MS during four weeks of shelf-life ripening after storage under four different storage conditions: ULO (ultra-low oxygen), DCA-CF (dynamic controlled atmosphere monitored by chlorophyll fluorescence), RLOS (repeated low oxygen stress) and 1-MCP (1-methylcyclopropene) in ULO. PTR fingerprint mass spectra of the apple headspace, obtained in short time without sample preparation or preconcentration, were sufficient to discriminate the four storage conditions during shelf-life. Moreover, we were able to monitor the changes in quality-critical VOC classes, including esters and terpenes, during shelf-life and observe the differential impact of the storage history on these VOCs. This work emphasizes the potential of PTR-MS as a valuable addition to targeted GC–MS-based approaches in postharvest research.