A treatment with 1-methylcyclopropene (1-MCP) is known to reduce softening to the flesh of ‘Rojo Brillante’ persimmon, which is the main chilling injury (CI) symptom that occurs after storage at low temperature. However, very little is known about the mechanism by which 1-MCP confers persimmon tolerance to chilling. The aim of this study was to investigate the changes in the redox system associated with CI and its reduction by 1-MCP during storage at 1 °C and after shelf life period. Our results showed that during cold store, both control and 1-MCP treated fruit underwent gradual oxidative stress (accumulation of H2O2, increment in APX, CAT, LOX, and slight increase in SOD activity) but no CI was manifested. During shelf life conditions, ethylene production was slightly higher in control than in 1-MCP treated fruit. Besides, the CI manifestation of control fruit was associated with oxidative burst [major H2O2 accumulation and sharp increase in catalase (CAT), peroxidase (POD), and lipoxygenase (LOX) activity], while 1-MCP treatment greatly reduced the CI symptoms. The 1-MCP treated fruit showed down-regulated POD activity and up-regulated CAT activity, which resulted in slower H2O2 accumulation. The reduction of the flesh softening as the main manifestation of CI in ‘Rojo Brillante’ persimmon by 1-MCP was associated with the modulation of the redox state of the fruit during the shelf life period that follows low-temperature storage.
Pedro Novillo, Alejandra Salvador, Pilar Navarro, and Cristina Besada
Cristina Besada, Alejandra Salvador, Lucía Arnal, and Jose María Martínez-Jávega
The effects of hot water treatments (HWTs) on chilling injury (CI) of ‘Rojo Brillante’ persimmon treated at different maturity stages and stored at 1 °C have been investigated. HWT temperatures ranging from 45 to 55 °C were applied for periods of time of between 2.5 and 40 min. Reduction of CI by HWT depended on the maturity stage. HWTs reduced softening when they were applied to fruit at an early stage of maturity, but caused skin cracking and skin browning in middle and advanced stages of maturity. Incidence and severity of these disorders increased as HWT temperatures and treatment times increased and in more mature fruit.
Ayoub Fathi-Najafabadi, Cristina Besada, Rebeca Gil, and Alejandra Salvador
Persimmon cultivation has significantly grown in the Mediterranean Region in recent years. The production concentrates mainly in three astringent cultivars: Kaki Tipo in Italy, Triumph in Israel, and Rojo Brillante in Spain. Therefore, the varietal range expansion is one of the current challenges for persimmon producers in this area. Moreover, the introduction of nonastringent persimmon cultivars is particularly interesting because they can be commercialized immediately after harvest without applying deastringency treatment before commercialization. This study evaluated the harvest period and the postharvest response of six Japanese nonastringent cultivars (Kanshu, Shinshu, Soshu, Suruga, Youhou, Izu). During two seasons, fruit from each cultivar were harvested at two maturity stages. Fruit quality (external color, firmness, and total soluble solids) was evaluated after harvest and after different commercial scenarios (domestic market: 7 days at 20 °C, market to European Union (EU): 5 days at 5 °C plus 5 days at 20 °C, and market to countries with cold-quarantine treatment requirements: 21 days at 0 °C plus 5 days at 20 °C). Cultivars Kanshu, Shinshu, Soshu, and Izu were identified as early cultivars, and Soshu was the earliest one, which reached commercial maturity at the beginning of September. These four cultivars showed good quality after simulating commercialization on domestic and EU markets. Cultivars Suruga and Youhou overlapped the current harvest window, but their low chilling injury sensitiveness is highlighted, so they are of special interest to be cold-stored at the end of the season to be commercialized in overseas markets.
Isabel Pérez-Munuera, Isabel Hernando, Virginia Larrea, Cristina Besada, Lucía Arnal, and Alejandra Salvador
The storage of persimmon cv. Rojo Brillante (Diospyros kaki L.) at low temperatures is limited by the susceptibility to chilling injury (CI), the main symptom being a drastic reduction of firmness when the fruit are transferred from low to moderate temperature. 1-Methylcyclopropene (1-MCP), an ethylene action inhibitor, has been shown to alleviate CI of persimmon, prolonging the storage period. In this article, the microstructural changes produced in the flesh of chilling-injured persimmon and fruit treated with 1-MCP were studied. The drastic softening displayed by chilling-injured fruit was related to a loss of cell wall integrity as well as to low intercellular adhesion. 1-MCP treatment alleviated CI by preserving the fruit firmness; it was linked to a preservation of the cell wall's integrity and to a higher intercellular adhesion observed during storage at low temperatures as well as when fruit were transferred to shelf temperatures.
Catarina P. Carvalho, Alejandra Salvador, Pilar Navarro, Adela Monterde, and Jose M. Martínez-Jávega
The degreening process is crucial in citrus fruit for the marketing of extra-early mandarins. Nevertheless, the application of ethylene during this treatment can be associated with calyx senescence. Citrus marketing regulations do not allow either alteration to fruit quality or the presence of calyx browning, especially on product exported to the United States. In this research, four synthetic auxins were tested for control of calyx disorders caused by degreening in different Clementine cultivars: Oronules, Clemenules, Marisol, and Clemenpons. All the tested auxins reduced calyx senescence, but the best results for all cultivars were obtained by 3,5,6-trichloro-2-pyridyloxyacetic acid followed by 2,4-dichlorophenoxyacetic acid isopropyl ester. In general, the higher the doses, the smaller the calyx alterations. The most susceptible cultivar to calyx senescence was ‘Marisol’, whereas ‘Clemenules’ and ‘Clemenpons’ were the most tolerant. Treated fruit presented lower weight loss than untreated fruit. Every treatment achieved the commercial color index and no sensory alteration was observed.