High CO2 is not the best option for blueberry postharvest quality

Blueberry is considered as an excellent source for polyphenols, which are highly needed for healthy diet. Accordingly, proper storage of blueberries, which is an essential component of cold marketing chain in modern time, has to reduce decay levels, maintain the content of berry polyphenols, and preserve firmness of the berries. Storage under high CO2 levels is widely practiced, although high CO2 levels may induce injuries to certain blueberry genotypes. Consequently, the aim of the study was explore the impact of various CO2 and O2 levels in store on changes in polyphenols profiles and firmness. Directly after picking fruits were stored at 0.0 ?C for eight weeks under the following controlled atmosphere conditions (O2%: CO2%): 21:1, 3:6, 3:12, 3:18, 10:6, 10:12, and 10:18. Results show that increasing CO2 to 18% led to drastic decreases in firmness. Moreover, reductions in the concentrations of specific polyphenols were also drastic under 18% CO2, in particular in combination with low O2 (3%). Among these polyphenols are: petunidin-3-arabinoside, (epi)catechin > (epi)catechin isomers, epicatechin, catechin, cyanidin arabinoside, petunidin hexoside, malvidin hexoside, malvidin arabinoside, cyanidin hexoside, delphinidin hexoside, and delphinidin arabinoside. Changes with another group of polyphenols were less drastic, with significant increases under 6 - 12% CO2. Among these are chlorogenic acid, kaempferol glucoside, and kuromanin. Coupled with that, the assessment of related genes shows that the expressions of chalcone synthase (VcCHS), dihydroflavonol reductase (VcDFR), anthocyanidin synthase (VcANS) genes were significantly higher by freshly harvested berries compared to stored berries. Storing berries under 18% CO2 resulted in highly reduced expressions of VcCHS and VcDFR compared to cold storage and storage conditions that involve 6% CO2. In conclusion, storing blueberries (cv. Duke) under 18% CO2 is not recommended, despite its positive effect in eliminating decay incidence. Original title, full list of authors, and sources: EXPLORING CHANGES IN POLYPHENOLS AND EXPRESSION OF RELATED GENES OF ?DUKE? BLUEBERRIES STORED UNDER STRESSFUL CO2 LEVELSHarb, J.1(*), Saleh, O.2, Kittemann, D.3, Neuwald, D.A.3, Hoffmann, T.4, Schwab, W.4 and Reski, R.2 jharb@birzeit.edu1 Birzeit University, Palestine2 Chair Plant Biotechnology, Freiburg University, Germany3 Komptenzzentrum Obstabau Bodensee, Ravensburg, Germany4 Program Biotechnology of Natural Products, Center of Life and Food Sciences, Technical University of Munich, Germany CA MA 2013, XI International Controlled & Modified Atmosphere Research Conference Trani (Italy), 3-7 June 2013 ? Blueberries are by fanpop.com ?