Atmosphere composition effects on Burlat cherry colour during cold storage

Carbon dioxide-enriched atmospheres are used to reduce the incidence and severity of cherry decay and to extend postharvest life. Freshly harvested Burlat cherries were placed in jars at 5 °C for 10 days and ventilated with five different atmospheres: (a) air, (b) 12% CO2-4% O2, (c) 12% CO2-20% O2, (d) 5% CO2-4% O2, and (e) 5% CO2-20% O2. Samples were analysed when harvested and after 5 and 10 days of cold storage. Best results were obtained with cherries kept in high-CO2 atmospheres, independently of O2 concentration. In these conditions the cherries present a higher acidity level (0.65 vs 0.60 g malic acid per 100 ml) and a lower anthocyanin content (0.40 vs 0.48 mg g^-1). As a consequence of this, h* (18 vs 20.5) and C* (24 vs 39) values are lower, which makes the cherries visually more reddish and less obscure and therefore more attractive for consumers. In addition, cherries kept in high-CO2 atmospheres present lower levels of peroxidase (469 vs 737 au g^-1) and polyphenoloxidase (73 vs 146 au g^-1) activities, which favours postharvest stability of colour.