The influence of different controlled atmosphere storage conditions on the storability and quality of blueberries cv. ‘Bluecrop’

Abstract

Blueberries cv. 'Bluecrop' were harvested and stored on the same day at 0 :!: 0.5 °C on various controlled atmosphere (CA) conditions, which involve two oxygen concentrations (18% and 2% 02) combined with four C02-concentrations (6%, 12%, 18%, and 24%). Cold storage in normal air represented 'control' treatment. After seven weeks in store, it was obvious that increasing C02-concentration led to a significat lower decay incidence. Furthermore, lowering 02-concentration, in combination with 12% and 18% CO2, led to a further reduction in decay incidence. Moderate CO2-concentration to 6% was of no advantage compared to cold-stored fruits. However, it was also obvious that increasing C02-concentration, in particular above 12%, accelerated the softening of berries,compared to berries stored under control or 6% C02 + 2% 02. Changes and differences in the total soluble solids values ( -sugar content) were non-significant between the treatments, whereas significant differences in the titritable acidity (TA) were observed. At harvest time, the TA value was already high, and increased steadily, in particular with berries stored under m()derate (6-12%) CO2-concentrations. Differences in the external quality, which was evaluated by a taste panel, between various CAstorage conditions were also non-significant, whereas major significant differences were assessed in respect to internal quality. All storage conditions with 18% and 24% C02, irrespective of 02-concentration, received bad evaluation, mainly due to off-flavour. In contrast, berries stored under 12% C02, but without lowering 02-concentration, were perceived as good, whereas berries stored under the same C02-concentration, but with a lowered 02-concentration, were scored as fruits of medium quality. In conclusion, it is possible to store blueberries cv. .Bluecrop' up to six weeks under 12% C02-concentration, but without any reduction in 02-concentration, which wi1l guarantee the preservation of the fruit firmness, combined with low decay incidence level and the absence of off-flavour and off-taste