Short-term high CO 2 treatment alleviates chilling injury of persimmon cv. Fuyu by preserving the parenchyma structure Cristina Besada a, * , Empar Llorca b , Pedro Novillo a , Isabel Hernando b , Alejandra Salvador a a Postharvest Department, Instituto Valenciano de Investigaciones Agrarias, Ctra Moncada N aquera Km. 4.5, 46113 Moncada, Valencia, Spain b Department of Food Technology, Universidad Polit ecnica de Valencia, Camino de Vera s/n, 46022 Valencia, Spain article info Article history: Received 13 August 2014 Received in revised form 30 October 2014 Accepted 7 November 2014 Available online 18 November 2014 Keywords: Persimmon Short-term high CO 2 treatment Chilling injury Flesh gelling Microstructure abstract Persimmon cv. Fuyu is chilling-sensitive and manifests chilling injury symptoms, flesh gelling and fruit darkening, during cold storage and subsequent shelf life. The objective of this study was to evaluate the effect of short-term high CO 2 treatments on chilling injury manifestation of ‘Fuyu’. Short-term high CO 2 treatments consisted in maintaining fruit in a 95% CO 2 atmosphere for 0, 12, 24 or 36 h before storage at 1  C. After 35 d and 50 d of low-temperature storage and after subsequent shelf-life periods of 5 d at 20  C, fruit quality and microstructural changes of flesh were evaluated. Our results showed that short- term high CO 2 treatments alleviate the main chilling injury symptoms, flesh gelling and fruit darkening. The longer the treatment, the greater chilling injury alleviation becomes. The microstructural study revealed that flesh gelling is associated with a complete disruption of cell walls and membranes, which led to the total loss of the initial parenchyma structure. Short-term high CO 2 treatment alleviated flesh gelling by preserving the integrity of cells walls and plasmalemma. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Persimmon fruit (Diospyros kaki L.), as many tropical and sub- tropical fruits, are sensitive to low temperature. The sensitivity of persimmon to chilling injury is cultivar-dependent; cultivars such as ‘Fuyu’, ‘Sugura’ or ‘Rojo Brillante’ are very chilling-sensitive, whereas others, such as ‘Triumph’ or ‘Hachiya,’ are no so suscep- tive to this disorder (Collins & Tisdell, 1995). Although chilling injury symptoms can vary depending on the cultivar, flesh texture disorders are reported in all sensitive cultivars as one of the main chilling injury manifestations. In ‘Fuyu’, which is a commercially important non-astringent persimmon in several countries, including Japan, Brazil, Korea, Australia and New Zealand, chilling injury is expressed initially in the form of a gel developing within flesh, and later by fruit darkening and increased skin transparency through which the characteristic gel can be seen (MacRae, 1987a). During not overly long storage periods, chilling injury symptoms usually appear when transferring fruits to shelf life temperatures. However during prolonged storage, such symptoms can eventually appear during cold storage (MacRae, 1987b). Since ‘Fuyu’ is free of astringency at harvest and does not require deastringency treat- ment, fruits are generally consumed “crisp”. Therefore preserving fruit texture is the main challenge when storing fruits (Park & Lee, 2005). Short-term anoxic treatment has been reported to alleviate the flesh firmness disorder associated with chilling damage in fruits such as avocado (Pesis, Marinansky, Zauberman, & Fuchs, 1993), kiwi (Song et al., 2009) or peach (Polenta, Budde, & Murray, 2005). Besides, other chilling symptoms such as browning of litchi (Liu et al., 2007) and avocado (Pesis et al., 1993), rind pitting of grape- fruit (Hatton, Cubbedge, & Grierson, 1975), and irregular ripening of tomato peel (Ibrahim, Rhani, & Buhri, 2013) are alleviated by short- term anoxic treatments. Several studies have suggested that the effect of postharvest disorder alleviation exerted by anoxic treatments might be related to their effect on the redox system, and finally on the cellular membrane. Thus in fruits such as kiwi, loquat or litchi, which were treated with short-term anoxia, enhanced activity of ROS scavenger enzymes (SOD, CAT or APX) and membrane integrity preservation have been associated with chilling injury alleviation (Gao et al., 2009; Liu et al., 2007; Song et al., 2009). In the persimmon cultivars belonging to the astringent group, short-term anoxic treatments based on high CO 2 concentration (80e95%) applied for 12e24 h have been widely studied because of * Corresponding author. Tel.: þ34 963424028. E-mail address: besada_cri@gva.es (C. Besada). Contents lists available at ScienceDirect Food Control journal homepage: www.elsevier.com/locate/foodcont http://dx.doi.org/10.1016/j.foodcont.2014.11.013 0956-7135/© 2014 Elsevier Ltd. All rights reserved. Food Control 51 (2015) 163e170