ABSTRACT. The present study aimed to investigate the effects of pre-storage for 24h and 48h and different modified atmosphere packaging-MAP treatments (using low-density polyethylene - LDPE) on the antioxidant compounds and the postharvest quality of ‘Douradão’ peaches under cold storage. The peaches were submitted to the following treatments: a control (no packaging or pre-storage) and pre-storage for 24h or 48h at 25ºC combined with passive MAP (LDPE 60 µm or 80 µm). After the application of the treatments, the fruits were stored at 0ºC for 30 days plus 3 days at 25ºC to simulate marketing conditions. The results showed that on the simulated marketing period, all the treatments (except for the control) reduced woolliness and internal browning. Furthermore, both pre-storage and LDPE MAP enhanced the polygalacturonase (PG) activity, the levels of phenolic compounds and the antioxidant capacity. Thus, these results suggest that the pre-storage associated with LDPE packaging increases the shelf life of peaches by up to 30 days under cold storage.

RESUMO O objetivo deste estudo foi desenvolver uma técnica simples para a remoção da adstringência, além de manter a firmeza de polpa de caqui ‘Giombo’. Os frutos foram colocados em diferentes tipos de embalagens plásticas: polietileno de baixa densidade (PEBD), polipropileno (PP) e polietileno-poliamida (PE-PA). As embalagens foram seladas a vácuo e tiveram dimensão de 30 cm x 50 cm e 20 micrômetros de espessura. Frutos não acondicionados em embalagens plásticas foram usados como controle. Após o embalamento, os frutos foram armazenados em condição ambiente (22oC e 70% UR) durante cinco dias. Após esse período, os frutos foram removidos da embalagem e colocados na mesma condição anterior por seis dias e avaliados a cada dois dias. Todas as embalagens plásticas demonstraram efetividade na remoção da adstringência, mas apenas o PE-PA manteve a firmeza durante os seis dias após a remoção dos frutos da embalagem. As embalagens com PEPD e PP causaram redução na adstringência enquanto a firmeza foi adequadamente mantida até o quarto dia em temperatura ambiente. Não foi possível obter vácuo nestes dois tipos de embalagem, apenas no PE-PA. O PE-PA reduz a adstringência mais rapidamente e mantém a firmeza por mais tempo em condição ambiente.

ABSTRACT The aim of this study was to develop a simple technique to remove astringency and maintain the pulp firmness of ‘Giombo’ persimmons. Fruit were packaged in three different plastic packages: low-density polyethylene (LDPE), polypropylene (PP) and polyethylene-polyamide (PE-PA). Packages with dimensions of 30 cm x 50 cm and 20 µm thickness were sealed under vacuum. Fruit uncovered in plastic film were used as control samples. After packaging, fruits were stored at ambient conditions (22°C and 70% RH) for five days. After this period, fruits were removed from the package and kept at the same previous conditions for six days and evaluated every two days. All plastic packages showed effectiveness in removing astringency, but only PE-PA maintained pulp firmness during the six days after package removal. LDPE and PP films also caused reduction of astringency while pulp firmness was properly maintained until the fourth day. These two films did not succeed in obtaining vacuum, which was only achieved by PE-PA. PE-PA reduces astringency faster and maintains fruit firmness for a longer time at room temperature.