BACKGROUND: Blood oranges are grown increasingly in Europe for fresh consumption because of their special taste and excellent nutraceutical properties that confer the status of a functional food. The health benefits are associated with the range of additional bioactive compounds that they contain with respect to blonde oranges.RESULTS: We analysed the physicochemical properties and the levels of organic acids, sugars and antioxidants in 11 blood orange cultivars representing the most representative cultivars of blood oranges widespread in the Mediterranean basin. In particular, we examined the levels of phenols, flavonoids and anthocyanins present in these cultivars at harvest maturity. The physicochemical, antioxidant and colour properties differ significantly among these cultivars. The deepest red peel and juice was found in Sanguinelli, followed by Tarocco Rosso and Moro. High‐performance liquid chromatography with refractive index detector analysis revealed sucrose as the main sugar in all these cultivars, followed by fructose and glucose. Citric acid was the dominant organic acid, followed by malic acid and ascorbic acid. Moro showed the greatest levels of antioxidant activity. Regarding the phenolic composition, we found p‐coumaric acid to be the main hydroxycinnamic acid in all cultivars, with maximum amounts in Moro and Sanguinelli. The highest amounts of cyanidin‐3‐O‐glucoside and cyanidin‐3‐(6′′‐malonyl)‐glucoside were found in Moro, for which the juice was of the deepest red colour.CONCLUSION: The phenolic composition and antioxidant activity of the 11 cultivars was assessed. The results showed that Moro was the cultivar with the highest content of polyphenols and levels of antioxidant activity, followed by Sanguinelli. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The loss of greenness (degreening) in citrus fruit during ripening is associated with autumnal falls in temperature, and there is a close correlation between the color of the fruit measured in the HunterLab space (colorimetric coordinate a) and the mean daily minimum temperatures recorded for the 7 and 21 days prior to the measurement being made. The term colorimetric coordinate a expresses the variation from green to yellow during lemon fruit ripening. In this work we attempt to determine the temperature below which degreening begins in three varieties of lemon fruit on the tree: Eureka, Lisbon and Fino. Only the results for Eureka are described since all three varieties showed the same behavior. The colorimetric coordinate a was measured weekly in the peel of previously marked and identified lemon fruit over a period of 7 years, and the temperature was recorded in a weather station situated on the same farm. The results show that degreening begins when the minimum temperatures fall below 10.5 °C for 2 days (not necessarily consecutive). In our experiment the mean daily minimum temperature recorded for the previous 7 and 21 days were 12.14 °C and 13.64 °C, respectively. This implies that a knowledge of autumn temperatures should enable growers to know when it is best to harvest the fruit – when degreening has just begun (with a shortened artificial degreening period) or when more time has elapsed, although this may mean that the commercial opportunity associated with early fruit may be lost.

With a progressively decreasing availability of water for irrigation, the utilization of lower agronomic quality water sources is becoming more prevalent. Compounds such as sodium and boron, due to their impact on crop development and production, are gaining significance in these water sources. Finding novel methods to immobilize these compounds in irrigation water is a top priority in the global agricultural sector. This study focused on exploring the potential of natural zeolite, commonly used as a soil improver and as a sorbent for sodium and boron in natural agricultural waters. The zeolite exhibited favorable properties, including a surface area of 40 m²/g and a cation-exchange capacity of 1.8 mg/g. Using a central composite factorial design, the zeolite’s capacity to remove sodium and boron from irrigation water was investigated. The results demonstrated significant efficiency in boron removal, while sodium removal was limited, with occasional desorption episodes. Response surface analysis revealed optimal conditions for the removal of each cation. Additionally, adsorption kinetics and pH effects were explored, emphasizing the influence on sodium sorption. Kinetic models were applied, and the pseudo-first-order model proved suitable for describing the sorption kinetics. These findings enhance our understanding of zeolite efficacy in irrigation water purification, emphasizing the complexity of cation interactions in “complex” solutions.