Controlled atmosphere storage impacts fruit quality and flavor chemistry of five cultivars of highbush blueberry (Vaccinium corymbosum)

Changes in highbush blueberry fruit quality and flavor chemistry following air or controlled atmosphere storage was determined for five blueberry cultivars. ‘Duke’, Aurora’, ‘Brigitta’, ‘Jersey’ and ‘Liberty’ fruit were stored for six weeks at 1 °C in chambers containing air or 0, 10.0, 12.5, 15.0, 17.5, or 20.0 kPa CO2 with 10.0 kPa O2. Elevated concentrations of CO2 reduced decay but did not affect fruit splitting, which differed among cultivars. Fruit firmness increased 36% in air-stored fruit, but decreased as CO2 concentration increased being 110% and 83% of initial values in fruit stored in 10 and 20 kPA CO2, respectively. Flesh discoloration increased following storage and in response to CO2 concentration. Sugar and acid content tended to increase in fruit stored in elevated CO2 concentrations but sugar/acid ratio declined. Volatile compounds were monitored using headspace solid phase microextraction-2 dimension gas chromatography-time of flight-mass spectroscopy. Concentrations of aldehydes did not change following storage regardless of atmosphere. Monoterpenoids and ketones declined after storage, but were not effected by storage atmosphere. Alcohols and esters increased after storage and in response to CO2 concentration. Ethanol, acetaldehyde and ethyl acetate increased in response to elevated concentrations of CO2 and were 1,100-, 90- and 150-fold greater in fruit stored in 20 kPa CO2 than in fruit prior to storage. Other ethyl and acetate esters also increased in response to elevated CO2 atmospheres. Differences in CO2 tolerance were observed among cultivars with ‘Liberty’ showing the least expression of fermentation-induced volatiles and ‘Aurora’ the least flesh discoloration. While storage of blueberries in elevated concentrations of CO2 is effective to reduce decay, its effects on fruit flavor must be considered in optimizing storage atmospheres.