Use of modified atmospheres to prolong the postharvest life of Burlat cherries at two different degrees of ripeness

The effects of degree of ripeness and packaging atmosphere on the quality of the very early season cherry (Prunus avium) cultivar ‘Burlat’ have been studied. Cherries were classified into two groups depending on their stage of ripening, taking colour as a maturity index (red and purple). After rapid chilling, cherries were sealed in 50 µm low-density polyethylene (LDPE) bags in four different atmosphere compositions. Packages were stored at 2 °C and cherries were analysed weekly until they were deemed to be commercially unacceptable (after 4 weeks for red cherries and 3 weeks for purple cherries). Changes in atmosphere composition, skin colour, pigment content, titratable acidity, soluble solids, firmness and sensory quality were monitored. Acceptability was higher for the less mature group of cherries. Colour shifted in both groups, initially from red to blue/red and later on back to red. Titratable acidity decreased at the end of the experimental period for all samples. Firmness increased at first, but towards the end of the experiment it was similar to the initial value. The gas composition of the four modified atmosphere conditions approached a final equilibrium consisting of 9–12% CO2 and 1–3% O2. For long-distance transportation of Burlat cherries the following procedure is recommended: harvest at the red colour stage, package in air using LDPE bags and maintain the temperature at 2 °C. Under these conditions, red Burlat cherries can be kept in an excellent commercial state for 3 weeks. © 2000 Society of Chemical Industry