Optimization of postharvest technology for "rojo brillante" persimmon and introduction of new varieties in the mediterranean area
- Autores: Ayoub Fathi Najafabadi
- Directores de la Tesis: Cristina Besada Ferreiro (dir. tes.), Amparo Alejandra Salvador Perez (dir. tes.), Isabel Hernando Hernando (tut. tes.)
- Lectura: En la Universitat Politècnica de València ( España ) en 2021
- Idioma: español
- Tribunal Calificador de la Tesis: Víctor Hugo Escalona Contreras (presid.), Gemma Moraga Ballesteros (secret.), Magda Andréia Tessmer (voc.)
- Programa de doctorado: Programa de Doctorado en Ciencia, Tecnología y Gestión Alimentaria por la Universitat Politècnica de València
- Materias:
- Enlaces
- Tesis en acceso abierto en: RiuNet
- Resumen
In the last two decades, persimmon production in Spain has increased exponentially and the cultivation area has expanded almost eight-fold. The current production of persimmon is focused on the cultivar 'Rojo Brillante', which is appreciated worldwide due to the high quality of the fruit. Nevertheless, centralized production of this single cultivar implies a major commercial limitation as its high volume of production is concentrated in a relative short harvesting period. Furthermore, it also implies a high phytosanitary risk.
In this context, this Thesis addresses two main objectives: 1) Optimization of pre- and postharvest technology in order to guarantee the quality of 'Rojo Brillante' persimmon after cold storage and transportation to overseas markets. 2) Evaluation of the behavior of foreign varieties of persimmon under Mediterranean conditions in order to extend the varietal range.
The first objective of this Thesis was tackled through the studies presented in Chapters I to V. The second objective was covered in Chapters VI and VII.
Chapter I dealt with the causes of internal browning disorder manifested after cold shipment of 'Rojo Brillante' persimmons to overseas markets. The temperature to which fruit is exposed immediately after CO2 deastringency treatment was identified as the main factor involved in this alteration. Our results showed that this disorder can be avoided by implementing an attemperation period of 24 h after the CO2 treatment, before transferring fruit to cold storage.
In Chapter II, the effectiveness of a recently patented deastringency treatment based on applying a new wax containing ethanol was assayed in 'Rojo Brillante' and 'Triumph' persimmons. The use of this new ethanol-based wax could be a potential alternative to the conventional CO2 deastringency treatment when the fruit are sent to distant overseas markets at low temperatures. Application of the new wax before cold storage led to loss of fruit astringency after 30 days at 0 °C while preserving fruit firmness and internal quality.
The results of Chapter III demonstrated that two applications of gibberellic acid (GA) made it possible to delay the fruit maturity process on the tree more than with just a single application. The combination of GA and 1-methylciclopropene (1-MCP) preserved the fruit quality better than with the application of 1-MCP alone during cold storage. Moreover, the fruit treated by multiple GA applications showed a slightly higher firmness after cold storage. However, a single GA application was also effective in preventing the manifestation of chilling injury (CI) in fruit.
Chapter IV demonstrated that in parallel to delaying maturity, the GA treatment also delayed calyx senescence, which meant that the fruit preserved a good appearance. The calyx lobe senescence during fruit ripening was linked to a decrease in all Chlorophyll Fluorescence Imaging (CFI) parameters (Fo, Fm, and Fv/Fm). Chapter V addressed the optimization of storage conditions for organic persimmons. According to our results, fruit harvested with a firmness lower than 30 N must not be stored. Fruit harvested with a higher level of firmness could be stored for up to three weeks depending on the storage conditions, the moment of application of the CO2 deastringency treatment, and the stage of fruit maturity. The longest storage period (3 weeks) was achieved when fruit were harvested with a firmness of around 45 N, submitted to CO2 treatment and then stored at 15 °C. Finally, 14 foreign varieties grown under Mediterranean conditions were evaluated to identify early- and late-season varieties with potential to extend the harvesting period. This is presented in Chapters VI and VII. In general, all the evaluated varieties fulfilled the quality criteria to be commercialized in domestic and European markets. However, sensitivity to CI was variety dependent and response to 1-MCP treatment was also observed to depend on the variety.
