Calcium applications throughout fruit development enhance olive quality, oil yield, and antioxidant compounds' content

Abstract

BACKGROUND Calcium is a preservative and firming agent largely used in the table olive industry. Foliar applications of calcium (as calcium chloride, CaCl2) before harvest have been proposed in other fruits to increase firmness and reduce physiological disorders or internal damage. However, there is still a shortage of information regarding the source, the concentration, the number, and the period of calcium application onto the canopy to get an effective response of olive quality. In this study, we aimed to investigate the effect of two concentrations of CaCl2 foliar treatments (0.5% and 1.0%), applied at different stages of fruit development (at the end of fruit set, end of pit hardening, and prior to harvesting), on olive quality for two varieties (‘Manzanilla de Sevilla’ and ‘Ascolanta tenera’), cultivated in two different geographical areas (Spain and Italy respectively). RESULTS The calcium concentrations applied enhanced the fruit calcium content and decreased sodium and potassium. They also improved the mechanical properties without modifying fruit morphology or cuticle thickness; nor did they cause phytotoxicity. Foliar treatments increased the oil content in the pulp (dry weight basis) and the amount of hydroxytyrosol, tyrosol, and oleuropein, among other phenols. CONCLUSION Calcium foliar applications during fruit development effectively increase olive quality. © 2020 Society of Chemical Industry

Foliar Calcium Effects on Quality and Primary and Secondary Metabolites of White-Fleshed ‘Lemonato’ Peaches

“…Moreover, neochlorogenic and cryptochlorogenic acids increased after the application of organic Ca, while the accumulation of chlorogenic acid was enhanced by CaCl 2 . In a previous study, CaCl 2 foliar application increased the phenolic content of olive fruit [40]. In our study, higher values of individual phenolics were usually found in the fruit from Agios Vlasios orchard.…”

Effect of Pre-Harvest Sprays with Calcium and Ascorbic Acid on Fruit Quality of Olive

“…Tsantili et al (2008) reported that calcium chloride spray three applications before harvested increased pulp of black-ripe 'Konservolia' olive. Morales-Sillero et al (2020) confirmed that calcium foliar sprays before harvest increased pulp oil content (dry weight basis), in addition to reduction of physiological disorders of green table olives.…”

Results of the BfR MEAL Study: The food type has a stronger impact on calcium, potassium and phosphorus levels than factors such as seasonality, regionality and type of production

“…For K and P, higher mean levels were found in organically compared to conventionally produced olives (763 to 212 mg kg −1 and 101 to 55.4 mg kg −1 , respectively) ( Table S3–S5 ). The 3-fold higher Ca levels in conventionally produced olives might be attributed to the application of calcium chloride as a food additive during fruit development and packaging to improve fruit quality and to increase preservability and texture ( Morales-Sillero et al, 2021 ). In contrast, 3.6 to 1.8-fold higher levels of K and P were found in organically compared to conventionally produced olives, respectively ( Table S4 and S5 ).…”