Cold storage of strawberries under high CO2 concentrations

Abstract

Temperature of 0°C associated to 12-20% CO2 has been recommended as the ideal conditions to store strawberries. However, fruits and vegetables are not currently handled under cold chain in Brazil and, when it happens, it used to be at 10 to 15°C. The goal of this work was to evaluate the quality and the shelf life of 'Oso Grande' strawberry at 10°C associated to high carbon dioxide concentrations. Strawberries were randomized, chilled and stored at 10°C in hermetic mini-chambers to apply the CO2 concentrations (0.03, 10, 20, 40 and 80%) plus 20% O2. Strawberries were analyzed every two days while they were proper to consumption. The shelf life for strawberries at 20 and 40% CO2 was 8 days, while those at 0.03% CO2 lasted only two days. Strawberries at 80% CO2 maintained good appearance for 6 days, but they were considered unsuitable for consumption due to high levels of acetaldehyde (40.92 μg g-1) and ethanol (1,053 μg g-1) that gave evidence of fermentation process. The weight loss was less than 2% showing how efficient was the method used to control the relative humidity during the storage. Strawberries at 0.03 and 80% CO2 levels showed higher firmness loss. Those fruits lost 40% of the initial firmness. Strawberries at 20 and 40% CO2 lost only 28% of initial firmness. Despite of the statistical effect of the treatments in the external color it was not visually perceptible. Strawberries stored at 10°C and 40% CO2 plus 20% O2 kept the marketable quality during 8 days.