Influence of Controlled Atmosphere and Dynamic Controlled Atmosphere on physiology, scald prevention and CA related disorders of ‘Abbè Fetel’ pears during long-term storage

Abbé Fétel pears harvested at two maturity stages, were stored in regular controlled atmosphere (CA) (3 kPa O2 and 2 kPa CO2), ultra low-O2 (0.7 kPa O2 and 0.8 kPa CO2), dynamic controlled atmosphere (DCA) (0.4-0.7 kPa O2 and 0.8 kPa CO2) and conventional air storage. The fruit were kept in metal cabinets at -1°C and inspected after 90, 120 and 180 days. During storage, within each picking period, ethylene production by the fruit was in the following descending order, air storage > regular CA > Low-O2 > DCA. The reverse for flesh firmness and green colour of fruit skin. Overall fruit metabolism was markedly lower in the first picking during 6 months storage. Low-O2 and DCA prevented superficial scald development at the end of each storage period followed by shelf life. Air storage was characterized by a significant incidence of superficial scald that was reduced by regular CA. In these storage conditions a close relationship between superficial scald and increase of conjugated trienols during storage was detected, while a significantly lower content was found in Low-O2 and DCA. The lowest incidence of superficial scald was detected in the second picking. All fruit batches, except those stored in air storage, developed soft scald, a CA storage related disorder. Low-O2 and DCA promoted the highest incidence. At the end of shelf life all the fruit stored at the various conditions softened at different rates and fruit yellowing was sensibly delayed by low-O2 and DCA. No brown core disorder was detected.