Effects of modified atmosphere packaging on ripening of 'Douradão' peach related to pectolytic enzymes activities and chilling injury symptoms

The present study evaluated the effects of modified atmosphere packaging on inhibition of the development of chilling injury symptoms in 'Douradão' peach after cold storage and the possible involvement of cell wall enzymes. Fruits were harvested at the middle stadium of ripening, packed in polypropylene trays and placed inside low density polyethylene (LDPE) bags (30, 50, 60 and 75 µm of thickness) with active modified atmosphere (10 kPa CO2 + 1.5 kPa O2, balance N2). The following treatments were tested: Control: peaches held in nonwrapped trays; MA30: LDPE film - 30 µm; MA50: LDPE film - 50 µm; MA60: LDPE film - 60 µm and MA75: LDPE film - 75 µm. Fruits were kept at 1±1ºC and 90±5% relative humidity (RH) for 28 days. After 14, 21 and 28 days, samples were withdrawn from MAP and kept in air at 25±1ºC and 90±5% RH for ripening. On the day of removal and after 4 days, peaches were evaluated for woolliness incidence, pectolytic enzymes activities. The respiratory rate and ethylene synthesis were monitored during 6 days of ripening. The results showed that MA50 and MA60 treatments had positive effect on the inhibition of the development of woolly texture and reduced pectin methylesterase activity on the ripe fruits, keeping good quality of 'Douradão' peach during 28 days of cold storage. The treatments Control, MA30 and MA75 showed higher woolliness incidence and did not present marketable conditions after 14 days of cold storage

Danos de frio e alterações qualitativas durante armazenagem refrigerada de pêssegos colhidos em dois estádios de maturação Chilling injuries and quality changes during cold storage of peaches harvested at two ripening stages

Pêssegos 'Chimarrita' e 'Chiripá' foram colhidos nas safras de 2000 e 2001, nos estádios de maturação de vez e maduro e armazenados a 0 ºC e 90% de umidade relativa. Os pêssegos 'Chiripá' permaneceram armazenados sob refrigeração por 10 ou 20 dias em 2000 e por 7, 14 ou 21 dias em 2001, enquanto os pêssegos 'Chimarrita' foram conservados em câmara frigorífica nas duas safras por 10, 20 ou 30 dias. Amostras de pêssegos foram avaliadas na colheita, em cada saída de armazenagem refrigerada e após 2 ou 3 dias de amadurecimento a 20 ºC. As perdas de massa fresca não foram afetadas pelo estádio de maturação nas duas cultivares. Em pêssegos com mais de 5% de perdas de peso após amadurecimento, observou-se enrugamento na região do ombro do fruto. Em 2001, a ocorrência de podridões foi maior nos pêssegos 'Chimarrita' colhidos maduros depois de transferidos a 20 °C. A firmeza da polpa diminuiu continuamente durante a armazenagem, principalmente nos frutos maduros. A firmeza dos pêssegos colhidos no estádio de vez foi significativamente maior que a dos pêssegos colhidos no estádio maduro enquanto sob refrigeração, mas após a transferência para 20 °C ela decresceu aos mesmos valores obtidos para os pêssegos colhidos mais maduros. Em 2001, após 30 dias sob refrigeração, observou-se lanosidade nos pêssegos 'Chimarrita' de ambos os estádios de maturação, enquanto apenas nos pêssegos 'Chiripá' de vez ocorreu lanosidade ao término da armazenagem refrigerada.<br>'Chiripá' and 'Chimarrita' peach cultivars were harvested in 2000 and 2001 at two ripening stages, mature green and tree ripe, and stored at 0 ºC and 90% relative humidity. 'Chiripá' peaches were cold stored for 10 or 20 days in 2000 and 7, 14 or 21 days in 2001. 'Chimarrita' peaches were stored in both years for 10, 20 or 30 days. Fruit samples were evaluated at harvest, at retrieval from each cold storage period and after two 2 or 3 more days of ripening at 20 ºC. Weight losses after storage of mature green and tree ripe peaches of both cultivars were similar. Peaches with more than 5% weight loss after retrieval from cold storage showed shriveling symptoms. Tree ripe 'Chimarrita' peaches after cold storage were more decayed in the 2001 season. Flesh firmness decreased continuously during storage, specially in tree ripe fruit. Flesh firmness of mature green peaches was significantly higher compared to ripe fruits. However, during ripening at 20 °C firmness values decreased to about the same values in both ripening stages. In the 2001 season, after 30 days in cold storage, 'Chimarrita' peaches of both ripening stages were woolly. In the same season, mature green 'Chiripá' peaches showed woolliness at the end of the storage period

Armazenamento de pêssego 'Chimarrita' em atmosfera controlada e sob absorção de etileno Storage of 'Chimarrita' peach in controlled atmosphere and under ethylene absorption

Foram conduzidos dois experimentos com o objetivo de avaliar o efeito de duas formas de absorção de etileno e de condições de atmosfera controlada (AC) sobre a qualidade do pêssego 'Chimarrita'. Os tratamentos do experimento 1 foram: testemunha com armazenamento refrigerado (AR); 1kPa de O2/3kPa de CO2; e 5kPa de O2/10kPa de CO2. No experimento 2, os mesmos tratamentos foram combinados com a absorção de etileno; absorção de etileno por filtro; e absorção de etileno por sache e sem absorção (testemunha). Tanto no experimento 1 como no experimento 2, os frutos foram armazenados na temperatura de -0,2&ordm;C. As avaliações realizadas após 45 dias de armazenamento refrigerado + 2 dias em temperatura ambiente demonstraram que o uso de AC manteve os frutos com maior acidez titulável e reduziu a incidência de podridões e esporulação de fungos. Após os dois dias a 20&ordm;C, os frutos armazenados em AC apresentaram-se mais firmes e com menor incidência de podridões e esporulação de patógenos. Os frutos mantidos na atmosfera de 5kPa de O2/10kPa de CO2 apresentaram maior incidência de lanosidade. No experimento 2, a absorção de etileno não foi eficiente na manutenção da qualidade do pêssego 'Chimarrita', mas após dois dias a 20&ordm;C reduziu a incidência de podridões.<br>Two experiments were carried out with the objective to evaluate the effects of two forms of ethylene absorption and controlled atmosphere (CA) storage on the quality of 'Chimarrita' peaches. The treatments of the first experiment were: control (cold storage); 1kPa O2/3kPa CO2; e 5kPa O2/10kPa CO2. In the second experiment the same treatments were combined to ethylene absorption; either absorption using a filter or absorption using a sachet and no absorption at all. In both experiments, the fruits were stored at -0,2&ordm;C for 45 days. At retrieval from storage, CA conditions maintained higher titratable acidity and reduced decay incidence and pathogen sporolution. After two days at 20&ordm;C, the fruits stored in CA were firmer had less decay and sporolated lesions. Fruits stored in 5kPa O2/10kPa CO2 had higher wooliness incidence. In experiment 2, the ethylene absorption was not effective for quality maintenance of 'Chimarrita' peaches, but after 2 days at 20&ordm;C, fruits stored with ethylene absorption were less decayed