EFFECT OF DIFFERENT CA CONDITIONS AND ETHYLENE LEVELS ON THE AROMA PRODUCTION OF APPLES

Golden Delicious apples were harvested in the preclimateric stage and stored for 8 months at 1 °C in air or in different controlled atmosphere conditions with or without ethylene removing. The aroma volatiles were measured during a 10 day shelf life period at 20 C following CA storage The production of aroma volatiles of CA stored fruits was highly suppressed at high C0₂ levels or low O₂ and ethylene levels. The C0₂ and the O₂ concentrations had the greatest influence on the aroma production, whereas the ethylene level had only a small importance. The EFE activity was also reduced by increasing CO₂ and reducing O₂ concentrations. The level of ethylene concentration in the store did not show any effect on the enzyme activity. Fruits stored in conventional CA conditions (3%CO₂/3%O₂) decreased more rapidly firmness and changed more intensively the skin colour from green to yellow when compared with ultra low oxygen (ULO) conditions (O₂ 1%). High ethylene concentration (100ppm) decreased the firmness but did not have any effect on the skin colour change.