Journal of the Science of Food and Agriculture J Sci Food Agric 87:824–831 (2007) Enriched ozone atmosphere enhances bioactive phenolics in seedless table grapes after prolonged shelf life Francisco Art ´ es-Hern ´ andez, 1 Encarna Aguayo, 1 Francisco Art ´ es 1∗ and Francisco A Tom ´ as-Barber ´ an 2 1 Postharvest and Refrigeration Group, Technical University of Cartagena, Paseo Alfonso XIII 48, E-30203 Cartagena, Murcia, Spain 2 Research Group on Quality, Safety and Bioactivity of Plant Foods, Food Science and Technology Department, CEBAS – CSIC, Apdo 164, E-30100 Espinardo, Murcia, Spain Abstract: ‘Autumn Seedless’ table grapes (Vitis vinifera L.) were stored for up to 60 days at 0 ◦ C under ten different gas treatments. An additional simulated retail display period of 7 days in air at 15 ◦ C was also applied in all cases. These postharvest treatments were tested as an alternative to the usual industrial SO 2 application and included modified atmosphere packaging (MAP), with and without natural fungicides (hexanal and hexenal), controlled atmosphere (CA) and intermittent and continuous applications of ozone (O 3 ). The sensory quality was preserved with MAP of 13 – 16 kPa O 2 + 8 – 11 kPa CO 2 , CA of 5 kPa O 2 + 15 kPa CO 2 and both O 3 treatments. Although O 3 did not completely inhibit fungal development, its application increased the total flavan-3-ol content at any sampling time. Continuous 0.1 μLL −1 O 3 application also preserved the total amount of hydroxycinnamates, while all treatments assayed maintained the flavonol content sampled at harvest. Total phenolics increased after the retail period in O 3 -treated berries. MAP preserved the total polyphenol content, while a slight decrease was observed under the CA conditions used. Therefore the improved techniques tested for retaining the quality of ‘Autumn Seedless’ table grapes during long-term storage seem to maintain or even enhance the antioxidant compound content.  2007 Society of Chemical Industry Keywords: Vitis vinifera L.; modified atmosphere packaging; controlled atmosphere; ozone; flavan-3-ols; flavonols; hydroxycinnamic acid derivatives; polyphenol content INTRODUCTION New table grape (Vitis vinifera L.) cultivars have become much appreciated and demanded by con- sumers owing to their seedlessness. The table grape is a non-climacteric fruit with low physiological activity and is sensitive to water loss and fungal infection, e.g. grey mould (Botrytis cinerea Pers.), during postharvest handling. For these reasons and according to com- mercial needs, table grapes can be cold stored with optimum quality for as long as 2–3 months under 90–95% relative humidity (RH), depending on the cultivar and maturity stage among other factors. After the cold storage and refrigerated transport period an additional 4–7 days at 12–18 ◦ C for retail display under ambient RH (55–65%) is usually applied. The most common method to control grape decay during cold storage for optimum quality at the end of this period is the use of SO 2 . Repeated fumigation with SO 2 or the use of in-package SO 2 generators may be applied. 1,2 In spite of its excellent ability to con- trol decay and stem browning, SO 2 application is not recommended for fresh fruits and vegetables 3 owing to allergic reactions in some consumers. In addition, SO 2 is highly corrosive to metals, is injurious to most other fresh fruits and causes injury to grapes if used excessively. 1 Consequently, alternatives to SO 2 are needed for table grape storage. Techniques that have already been tested successfully on table grapes include modified atmosphere packaging (MAP), 4–6 controlled atmosphere (CA), 5–9 natural antifungal volatile com- pounds extracted from plant tissues, e.g. hexanal and (E)-2-hexenal, 10,11 and the use of O 3 . 12,13 Phenolic compounds are plant secondary metabo- lites of variable chemical nature and biological proper- ties that play an important role in the sensory quality attributes of fruits and vegetables. 14 Their poten- tial health-promoting properties for consumers have been widely recognised and related to their antioxi- dant activity or inhibition of low-density lipoprotein (LDL) oxidation. This is correlated with a low inci- dence of cardiovascular diseases and some types of cancer. 15 – 19 However, it has also been shown recently that total or specific fruit and vegetable intake is not associated with risk of other cancer types, e.g. breast cancer, 20 and evidence for a protective effect of fruits ∗ Correspondence to: Francisco Art ´ es, Postharvest and Refrigeration Group, Technical University of Cartagena, Paseo Alfonso XIII 48, E-30203 Cartagena, Murcia, Spain E-mail: fr.artes@upct.es Contract/grant sponsor: CICYT-FEDER, Spain; contract/grant number: 1FD-0760-C03-01 (Received 4 October 2005; revised version received 28 June 2006; accepted 5 July 2006) Published online 12 February 2007; DOI: 10.1002/jsfa.2780  2007 Society of Chemical Industry. J Sci Food Agric 0022–5142/2007/$30.00