Available online at www.sciencedirect.com Postharvest Biology and Technology 46 (2007) 230–236 Headspace fingerprint mass spectrometry to characterize strawberry aroma at super-atmospheric oxygen conditions Amalia Z. Berna a , Sabine Geysen b , Sun Li a , Bert E. Verlinden b , Jeroen Lammertyn a,∗ , Bart M. Nicola¨ ı a a BIOSYST-MeBioS, Katholieke Universiteit Leuven, Willem de Croylaan 42, B-3001 Leuven, Belgium b Flanders Centre of Postharvest Technology, Willem de Croylaan 42, B-3001 Leuven, Belgium Received 14 June 2006; accepted 15 May 2007 Abstract This paper reports on the relation between super-atmospheric oxygen packaging and aroma production in strawberries. Volatile compounds were extracted from the headspace of strawberries stored at 7 ◦ C for 0, 4 and 7 days under different gas conditions. Super-atmospheric oxygen concentrations were applied in combination with or without elevated CO 2 concentrations and the volatile production was measured with GC–MS. The potential of headspace fingerprint mass spectrometry (HFMS), a rapid technique for aroma profiling, was evaluated. Canonical discriminant analysis (CDA) based on the 16 most abundant volatile compounds and 26 HFMS signals (m/z) was applied to discriminate the samples according to gas storage treatment. The results showed that after 4 and 7 days of storage under super-atmospheric oxygen concentrations (without carbon dioxide) the production of ethyl acetate was suppressed. Ethyl acetate is one of the most important off-flavors in strawberries. Samples treated with only oxygen were mainly characterized by the ester methyl hexanoate with pineapple notes. Similar results were obtained with HFMS. CDA also showed that it is possible to classify samples according to days of shelf-life and that the effect of gas conditions was smaller than the effect of days of shelf-life. © 2007 Elsevier B.V. All rights reserved. Keywords: Strawberries; Headspace fingerprint mass spectrometry; High oxygen; Modified atmosphere; Aroma 1. Introduction Common postharvest practices used to control strawberry decay are based on the use of low temperatures (0–2 ◦ C) and high CO 2 concentrations as modified atmospheres (up to 15–20%) (P´ erez and Sanz, 2001). These conditions are used to control grey mold in strawberries, caused by Botrytis cinerea Pers., which is the most economically significant postharvest pathogen on strawberry fruit, causing up to 50% loss. Carbon dioxide treated strawberries are firmer and less susceptible to decay than air-stored fruit. However, the atmospheres necessary for decay control are often close to the level of product tolerance. Improper modified atmosphere (MA) packaging can initiate or aggra- vate physiological disorders, causing irregular fruit ripening and off-flavor production and can even increase decay susceptibil- ity (Wszelaki and Mitcham, 2000). Continued presence of an ∗ Corresponding author. Tel.: +32 16 321459; fax: +32 16 322955. E-mail address: jeroen.lammertyn@biw.kuleuven.be (J. Lammertyn). elevated CO 2 environment induces a concomitant decrease in the pH of the fruit that leads to a deleterious aroma. Straw- berry off-flavor has been associated with the accumulation of acetaldehyde, ethanol, and ethyl acetate formed through fermen- tation pathways. Nevertheless, Ke et al. (1994) proposed that the aroma of controlled-atmosphere (CA) stored strawberries was altered not only by overproduction of acetaldehyde and ethanol but also by a reduced production of some volatile esters. The application of novel gas mixtures (e.g. high O 2 , argon and nitrous oxide) are new approaches for designing modified atmo- spheres (MA) capable of overcoming the many disadvantages of the current high CO 2 and/or low O 2 in MA and CA. High O 2 atmospheres have proved to be particularly effective at inhibiting enzymatic discoloration, preventing anaerobic fer- mentation reactions, and inhibiting microbial growth (Kader and Ben-Yehoshua, 2000). These authors have published work on the response of fresh fruit and vegetables (plums, pear, potato, cher- ries, apricot, tomatoes, onions, apples, etc.) to super-atmospheric O 2 concentrations alone and in combination with elevated CO 2 atmospheres. Stewart et al. (1999) reported the effects of high-O 2 0925-5214/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.postharvbio.2007.05.011