ACTIVE PACKAGING DEVELOPMENT TO IMPROVE ´STARKING´ SWEET CHERRY POSTHARVEST QUALITY

Abstract

'Starking' sweet cherry belongs to the Denominacion Especifica Cereza de la Montana, Alicante, Spain and is considered a late season cultivar in this area with several problems for commercialisation mainly due to incidence of decay and a fast loss of sensory quality, both for fruit and green stem. Based on this issue, an active packaging has been developed based on the addition of 1 mL eugenol (essential oil from oregano) to trays and then sealed with polypropylene bags to generate a modified atmosphere (MAP). Also, cherries in MAP (without eugenol) and non-packaged fruits were selected and served as controls. Both bags and non-packaged cherries were stored during 16 days at 2°C and 90% RH. Samples were taken after 2, 6, 9, 13 and 16 days in which the internal atmosphere composition, weight loss, colour, °Brix-titratable acidity ratio, firmness, visual aspect of the stem and microorganism proliferation were evaluated. Steady state atmosphere was reached after 9 days of cold storage with 2-3% of CO 2 and 10-11% of O 2 with no significant differences between treated and control. When fruit quality parameters were determined, those treated with eugenol showed a significant reduction in weight loss compared with control, either under MAP or not. Contrarily, colour parameter L* and fruit firmness remained significantly higher during storage in treated cherries than in controls, under MAP or not. °Brix-titratable acidity ratio increased during storage in control fruits, while no significant changes were observed under MAP storage. When the stem was evaluated, this remained green in cherries stored in MAP, while they became brown in control. Finally, the microbial analysis showed that eugenol treatment reduced yeast, mold and total aerobic mesophylic colonies 2 and 3-log CFU compared with control under MAP or not, respectively. In conclusion, the use of MAP in combination with eugenol is an effective tool on maintaining cherry fruit quality and reducing the occurrence of decay.