Quality of green (Actinidia chinensisvar.deliciosa‘Hayward’) and yellow (A. chinensisvar.chinensis‘Soreli’) kiwifruit during cold storage at 0°C in normal atmosphere and with gaseous ozone

Post-Harvest Quality Evaluation of “Soreli” Kiwifruit at Two Ripening °Brix Values from Vineyards of Different Age under Hail Nets

The application of anti-hail nets is a practice that has been employed for a long time on different fruit and vegetable cultivations and in different fields of the world. In this work, we checked the effects of shading with white anti-hail nets on the post-harvest quality of “Soreli” kiwifruit collected at two different °Brix (7–8 and 8–9) from vineyards of two different ages (8 and 9 years) and stored at 1 °C for 90 days. It was observed that during the storage, the firmness and color parameters (L*, a*, b*, and Chroma) and the SSC content were generally higher in kiwifruit samples harvested in open field than in those under the nets. Regarding the bioactive compounds, the open field samples showed higher values in total flavonoids content during storage, and the content of carotenoids and chlorophylls in fruits grown in open fields was higher from 30–45 days up to the end of the storage. In contrast, the polyphenols and ascorbic acid values of fruits in open fields and under the nets showed a similar evolution of the values from 45 to 60 days. In general, the early and late harvest time based on the °Brix values and the different ages of the kiwifruit plants under the nets did not affect the quality parameters.

Ozone and Bioactive Compounds in Grapes and Wine

Ozone is widely used in the agri-food and food processing industries mainly as a sanitizing agent. However, it has recently become clear that ozone exposition leads to another important benefit: in living tissues, the induced-oxidative stress triggers the antioxidant response, and, therefore, it enhances the production of antioxidant and stress-related secondary metabolites. As such, ozone can be considered an abiotic elicitor. The goal of the present review was to critically summarize knowledge about the possibility of improving bioactive compounds and, consequently, the health-related properties of grapes and wine, by using ozone. The greatest interest has been given not only to the pre- and post-harvest treatment of table and wine grapes, but also to the explanation of the mechanisms involved in the ozone-related response and the main secondary metabolites biosynthetic pathways. From the literature available, it is clear that the effect of ozone treatment on health-related properties and secondary metabolites accumulation depends on many factors, such as the cultivar, but also the form (water or gaseous), doses, and application method of ozone. Most of the published papers report an increase in antioxidant compounds (e.g., polyphenols) and stress-related volatiles, confirming the hypothesis that ozone could be used to improve berry and wine compositional and sensory quality.

Response of antioxidant system to postharvest ozone treatment in 'Soreli' kiwifruit

BACKGROUND

Among the challenges for postharvest researchers is that of understanding the physiological and biochemical pathways associated with postharvest fruit decay. Fruit senescence directly affects sensorial and nutritional quality during postharvest life. It has been clarified that reactive oxygen species and oxidative damage are responsible for fruit senescence. Some cultivars of yellow-fleshed kiwifruit can be stored for a short period compared with green-fleshed kiwifruit. Postharvest performance is affected by the physiological state of the fruit at harvest, associated with its postharvest management. Among several postharvest applications, ozone treatment is considered as a cost-effective and eco-friendly food-processing technology to preserve the fruits' quality during cold storage. In this study, we investigated the influence of ozone, after gradual cooling treatment, on the antioxidant defense system in Actinidia chinensis, 'Soreli'.

RESULTS

Bioactive compound content decreased during cold storage, and ozone treatment enhanced the activities of superoxide dismutase and catalase during cold storage. This treatment preserved membrane integrity by inhibiting lipoxygenase activity and malondialdehyde accumulation. A multivariate statistical approach, using principal component analysis, provided the global response to the effect of ozone postharvest treatment during cold storage in kiwifruit 'Soreli'.

CONCLUSION

Ozone treatment improves the efficiency of antioxidative system and storability of 'Soreli' kiwifruits. © 2019 Society of Chemical Industry.

Effects of ozone postharvest treatment on physicochemical and qualitative traits of Actinidia chinensis 'Soreli' during cold storage

BACKGROUND

Ozone has been used for improving the postharvest life of fruits and vegetables. Ozonation, an alternative decontamination method, can be applied effectively to perishable commodities immediately after harvest. Kiwifruit is a subtropical climacteric fruit that is less able to acclimate and is susceptible to low temperatures. In this study, we investigated the influence of ozone and different storage temperatures on the physico-chemical and qualitative features in Actinidia chinensis 'Soreli'. The fruits were treated with a continuous flow of ozone in air (300 ppb), stored at 2 and 4 °C for 60 days, and sampled every 15 days.

RESULTS

It was found that ozone treatment induced the ripening process; this was evident at the end of the storage, with higher soluble solids content for ozone-treated fruits at 2 and 4 °C. Storage temperatures and gaseous ozone treatment influenced in a different manner the bioactive compounds, such as polyphenols, flavonoids, ascorbic acid, and carotenoids. Additionally, under gaseous ozone storage, microbial growth was delayed, improving the microbial quality index when the fruits were stored at the lowest storage temperature (2 °C). Principal component analysis highlighted that the effects of storage temperature on physico-chemical and bioactive compounds were greater than the postharvest treatment.

CONCLUSION

Storage temperature influenced the postharvest life of 'Soreli'. Storage at 2 °C and under 300 ppb gaseous ozone improved the yellow-fleshed fruit storage life. However, storage at 4 °C under 300 ppb gaseous ozone did not show advantages in preserving the fruit quality. © 2019 Society of Chemical Industry.