Responses of fruit physiology and virgin oil quality to cold storage of mechanically harvested ‘Arbequina’ olives cultivated in hedgerow

Abstract

RESUMENRespuestas de la fisiología del fruto y de la calidad del aceite virgen al almacenamiento en frío de aceitunas 'Arbequina' de seto cosechadas mecánicamente El aumento de la producción de aceituna (Olea europaea L. cv. 'Arbequina'), debido al uso creciente del cultivo superintensivo y la necesidad de un rápido procesamiento del fruto forzará a la industria a hacer una considerable inversión en maquinaria para el procesado, para mantener el nivel de calidad del aceite de oliva virgen (AOV). Este trabajo pretende estudiar cómo la temperatura de almacenamiento afecta a la fisiología de la aceituna y a la calidad del aceite, en orden de usar la conservación del fruto como una alternativa más barata y versátil al aumento de la capacidad de procesamiento. La aceituna 'Arbequina' no presentó síntomas de daños por frío durante 15 días de frigoconservación. La podredumbre, el desverdizado, el ablandamiento, la respiración y la producción de etileno de la aceituna aumentaron en relación directa a como aumentaba la temperatura de conservación. Estos hechos determinaron un deterioro proporcional de la acidez libre y de la calidad sensorial de los AOVs. Además, los contenidos de tocoferoles y de los principales grupos de compuestos fenólicos en los AOVs experimentaron una reducción durante la conservación del fruto en razón directa a la temperatura de almacenamiento utilizada. La frigoconservación a 2 °C preservó la integridad del fruto para mantener el nivel «Extra» de calidad durante un periodo de 12 días. PALABRAS CLAVE: Ablandamiento del fruto -Color del fruto -Compuestos fenólicos -Etileno -Olea europeaPoscosecha de aceituna -Respiración -Tocoferoles. SUMMARY Responses of fruit physiology and virgin oil quality to cold storage of mechanically harvested 'Arbequina' olives cultivated in hedgerowThe increase in olive fruit production (Olea europaea L. cv. 'Arbequina'), due to the increasing use of super-intensive cultivation and the need for a rapid fruit processing will force the industry to make a considerable investment in machinery for processing in order to maintain the level of quality of virgin olive oil (VOO). This work aims to study how the storage temperature affects the physiology of the olive and the quality of the oil, in order to use fruit storage as a cheaper and more versatile alternative to the increase in processing capacity. 'Arbequina' fruit did not present symptoms of chilling injury during 15 days of cold-storage. Postharvest decay, de-greening, softening, respiration and ethylene production of the olive fruit increased in direct relationship as the storage temperature increased. These facts determined a proportional deterioration of the free acidity and the sensory quality of the VOOs. Furthermore, the contents of tocopherols and of the main phenolic compounds in the VOO exhibited a reduction during fruit storage according to the increase in the temperature used. Storage at 2 °C preserved the integrity of the olive to maintain the best "Extra" level of VOO quality for a period of 12 days.

Characterisation of Arbequina Extra Virgin Olive Oil from Uruguay

“…Arbequina is a cultivar typical of the Spanish region of Catalunya (Terragona and Lé rida) and of Alto Aragón. It adapts easily to new environmental conditions and, because of its small size, precocity, high oil yield, good oil quality, and other agronomic characteristics, is particularly fit for new high-density olive orchards and mechanised cultivation (Rondanini, Castro, Searles & Rousseaux, 2011;Yousfi, Weiland & Garcí a, 2013;Borges et al, 2017). Furthermore, Arbequina olive oil is highly appreciated for its mild taste and is considered ideal for new and emerging markets compared to other oils, which can be more bitter and pungent (B. Jimé nez & Carpio, 2008;Borges et al, 2017).…”

Olive Fruit Refrigeration during Prolonged Storage Preserves the Quality of Virgin Olive Oil Extracted Therefrom

“…A significant effect of different storage temperature on the chlorophyll content was not observed in RO oils, probably because its fruits did not continue to ripen during storage (Table 1), while fruit injuries as a result of freezing during storage were not observed by visual inspection. Yousfi et al [10] also found that storage conditions (3 • C and 18 • C during 3 weeks) did not affect the content of chlorophylls in Arbequina fruits.…”

“…Foods 2020, 9, x FOR PEER REVIEW 6 of 17 storage (Table 1), while fruit injuries as a result of freezing during storage were not observed by visual inspection. Yousfi et al [10] also found that storage conditions (3 °C and 18 °C during 3 weeks) did not affect the content of chlorophylls in Arbequina fruits. In case there were no statistically significant differences the letters were omitted.…”

“…This result indicates that the accumulation of oil did not continue during fruit storage, which is in agreement with the findings of Inarejos-García et al [37] during the storage of Cornicabra cultivar fruits at 10 • C and 20 • C for three weeks, and that of Yousfi et al [23] in the case of Arbequina olives stored up to three weeks at 3 • C and 18 • C. On the other hand, considering the processing parameters, olive oil yield and extractability index (EI), the highest values were obtained in the case of storage at RT (Table 1). Yousfi et al [10] reported that olives stored under ambient temperature (18 • C) exhibited higher respiration rates than refrigerated ones, which is associated with fruit ripening and, consequently, softening. As a consequence of ripening, degradation of walls of oil-bearing cells is facilitated and the extraction process is improved, which could have been the cause of the increase of the olive oil yield and EI in the RT stored fruits in this study.…”

“…Carotenoids content was not significantly changed depending on the fruit storage temperature in both IB and RO oils, except in the case of RO-20 oil where an increase was detected when compared to RO-control oil (Figure 1). Yousfi et al [10] have found that carotenoids were not affected by the storage conditions (3 °C and 18 °C during 3 weeks) applied to the Arbequina fruits. The increased content of carotenoids in RO-20 could be related to a decrease in the consistency of the chloroplast wall caused by low storage temperature that facilitates the release of these pigments into olive oil [23].…”