Browsing by Author "Zoffoli, Juan P."

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    Determination of optimal sulfur dioxide time and concentration product for postharvest control of gray mold of blueberry fruit
    (2013) Rivera, Sebastian A.; Zoffoli, Juan P.; Latorre, Bernardo A.
    Highbush blueberries (Vaccinum spp.) are a major export fruit crop of Chile which is stored at 0 degrees C and transported to markets in Asia, Europe, and the USA, using more than 15 d of maritime transportation. Under these conditions, gray mold caused by Botrytis cinerea can produce important economic losses. The effectiveness of sulfur dioxide (SO2) concentration x time treatments on gray mold control was determined in the laboratory and validated prior to refrigerating the fruit, using pallet scale SO2 fumigation treatment on the following blueberry cultivars: 'Brigitta', 'Legacy', 'Liberty' and 'O'Neal'. In inoculated 'Brigitta' and 'Liberty' blueberries, gray mold prevalence varied from 97.2% to 97.5% in non-treated fruit, and this value was reduced from 7.9% to 6.1% in blueberries that were exposed to a SO2 concentration x time (Ct) product of 400 (mu L L-1) h. The relationship between SO2 Ct products and gray mold prevalence under laboratory conditions was best explained by exponential models, which had a determination coefficient (R-2) that ranged from 0.88 to 0.96. The estimated EC90 values varied between 245 and 400 (mu L L-1) h, and the SO2 Ct between 250 and 350 (mu L L-1) h was validated using a pallet scale application treatment to obtain the best control and minimal variation. No visual phytotoxicity symptoms of SO2 were observed with the Ct that was tested in this study. Therefore, SO2 fumigation was demonstrated to be an effective and practical technology for reducing the risk of blueberry gray mold decay during storage, and further effort should be given to register the use of this product for blueberries in the main Chilean export markets. (C) 2013 Elsevier B.V. All rights reserved.
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    Influence of preharvest environmental conditions and postharvest relative humidity on the appearance of orange peel disorder in sweet cherry during fruit development and storage
    (2024) Coye, Francisca; Calderon-Orellana, Arturo; Zoffoli, Juan P.; Contreras, Carolina
    Orange peel, a physiological disorder, has been reported in Chilean sweet cherries ( Prunus avium (L.) L.) after 35-45 d under modified atmosphere packaging (MAP). The ontogeny of the disorder is unknown, and preharvest factors have not been thoroughly investigated. This study involved two experiments to elucidate the association between environmental factors and the incidence of the orange peel disorder. In the first experiment, plant water potential, fruit position on the tree, relative humidity (RH), and radiation of sweet cherry trees were studied in 'Regina', 'Kordia', and 'Lapins'. The second experiment focused on the interaction effect of heat during fruit development and the RH during storage in 'Lapins'. The first experiment showed no clear response of orange peel incidence to natural variations in air temperature, vapor pressure deficit, and transmitted solar radiation (PPFD) within trees. However, significant differences in the incidence, severity, and timing of the disorder detection were observed among cultivars. In 'Lapins', orange peel disorder began before harvest in the green stage, 33.7 %, while 'Regina' and 'Kordia' showed negligible incidences of 1.25% and 0%, respectively. At postharvest, no differences were found among tree sections, either in incidence or severity of the disorder. For the second experiment, no differences in incidence were found in heated fruit during preharvest or postharvest RH treatments. However, it was observed that the higher the RH (100%), the lower the severity index (3.6) was for the orange peel disorder. The high incidence of the disorder during postharvest under natural or induced environmental conditions in the three cultivars evaluated demonstrates that RH mainly affects the orange peel disorder.
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    Ultra-Low Oxygen and Preconditioning Storage Regulate Ethylene Synthesis to Prevent Corky Disorders in 'Fuji' Apple
    (2022) Riano, Camila; Ribba, Tomas; Marchant, Juan I.; O'Brien, Jose A.; Contreras, Carolina; Zoffoli, Juan P.
    Corky disorders in apples represent a significant problem for long-term storage where controlled atmosphere (CA) is mainly used. Ultra-low oxygen (ULO) is an alternative to CA, which consists of low partial pressure of O-2 to maintain a low metabolism in the apple fruit, achieving an effective decrease in the ethylene production and physiological disorders. The aim of this research was to study the effectiveness of a short hypoxia period on the development of cork physiological disorders during the storage of apple. 'Fuji' apples were prestored under ULO (0.5 kPa O-2) for two periods of time (15 and 30 days) and at two temperatures (0 or 5 degrees C). Corky physiological disorders increased at 5 degrees C prestorage temperature; however, ULO treatments for 15 or 30 days at 0 or 5 degrees C achieved a significant reduction in corky disorders near to 1%, compared with control treatments. In addition, a considerable reduction in ethylene production for up to 30 days was observed in ULO-treated fruit at 0 and 5 degrees C. ULO for 30 days at 0 and 5 degrees C increased the internal production of ethanol and acetaldehyde, causing a lower sensory quality due to the presence of fermentative flavors in fruit stored at 5 degrees C. ULO of 15 days of conditioning decreased the relative expression of ethylene biosynthesis genes MdACS1 and MdACO1, resulting in lower ethylene production.