Olive Oil Yield Research Articles

Utilizing Olive Fly Ecology Towards Sustainable Pest Management

The olive fly (Bactrocera oleae, OLF) is a major pest of global significance that occurs in places where olive cultivation thrives. This paper highlights the economic and environmental damage caused by OLF infestations, including reduced olive oil yield and quality, disrupted supply chains, and ecosystem imbalances due to heavy insecticide use. Understanding olive fly ecology is crucial for developing effective control strategies. The review explores the fly’s life cycle, its relationship with olive trees, and how environmental factors like temperature and humidity influence population dynamics. Additionally, studying the role of natural enemies and agricultural practices can pave the way for sustainable control methods that minimize environmental harm. Climate change, intensive cultivation, and the development of resistance to insecticides necessitate a shift towards sustainable practices. This includes exploring alternative control methods like biological control with natural enemies and attract-and-kill strategies. Furthermore, a deeper understanding of OLF ecology, including its response to temperature and its ability to find refuge in diverse landscapes, is critical for predicting outbreaks and implementing effective protection strategies. By employing a holistic approach that integrates ecological knowledge with sustainable control methods, we can ensure the continued viability of olive cultivation, protect the environment, and produce high-quality olive oil.

How the "Olive Oil Polyphenols" Health Claim Depends on Anthracnose and Olive Fly on Fruits.

Olive anthracnose, caused by Colletotrichum fungi, and the olive fruit fly Bactrocera olea are, respectively, the most important fungal disease and pest affecting olive fruits worldwide, leading to detrimental effects on the yield and quality of fruits and olive oil. This study focuses on the content of hydroxytyrosol (HYT) and its derivatives (the "olive oil polyphenols" health claim) in olive oils extracted from fruits of 'Galega Vulgar' and 'Cobrançosa' cultivars, naturally affected by olive anthracnose and olive fly. The olives, with different damage levels, were harvested from organic rainfed orchards, located in the center of Portugal, at four harvest times over three years. Galega oils extracted from olives with a higher anthracnose and olive fly incidence showed no conformity for the extra virgin olive oil (EVOO) and virgin olive oil (VOO) categories, presenting high acidity and negative sensory notes accompanied by the disappearance of oleacein. Conversely, no sensory defects were observed in Cobrançosa oils, regardless of disease and pest incidence levels, and quality criteria were still in accordance with the EVOO category. The total HYT and tyrosol (TYR) content (>5 mg/20 g) allows for the use of the "olive oil polyphenols" health claim on the label of all the analyzed Cobrançosa olive oils.

The Management of Irrigation and Potassium Fertilization to Mitigate the Effect of Light Frosts on the Phenolic and Volatile Compounds in Virgin Olive Oils.

The frequency of early frosts has increased in recent years, which are injurious to olive growing, causing losses in the yield and quality of virgin olive oil. In this research, it was studied how the management of agronomic factors mitigates frost damage in Arbequina olives, minimizing the loss of phenols and volatiles in virgin olive oil, at different fruit ripening stages. A Box-Behnken design and multivariate analysis were performed, with three levels of irrigation, potassium fertilization, and foliar copper application (15 treatments). Virgin olive oil was extracted from fresh and frozen olives. Light frost caused a significant decrease in the total phenols and secoiridoid compounds in and the antioxidant capacity of the frost-affected oils, which were perceived as more pungent and had the slight defect of "frostbitten olives". According to the Box-Behnken design, an 86% reference evapotranspiration (ET0) or higher with 100 potassium oxide units (UK2O) and a 100% ET0 or higher with 250 UK2O would be required to minimize the effect of light frost on phenols and volatiles. Partial Least Squares Regression-Discriminant Analysis (PLS-DA) differentiated the virgin olive oils according to their ripening stage and fresh and frost conditions. Moreover, PLS-DA positively correlated a 75-100% ET0 and 0 Uk2O with the dialdehydic form of the decarboxymethyl ligstroside aglycone (p-HPEA-EDA), the dialdehydic form of the decarboxymethyl oleuropein aglycone (3,4-DHPEA-EDA), the dialdehydic form of the ligstroside aglycone (p-HPEA-EDA-DLA), and with fruity, pungent, and bitter attributes. Precision agronomic management based on the needs of the crop itself would avoid unnecessary stress on olive trees and oil damage.

Pulsed electric field treatment improves the oil yield, quality, and antioxidant activity of virgin olive oil

Pulsed electric field (PEF) is an innovative technique used to assist in the extraction of vegetable oils. There has been no research on the effects of PEF on virgin olive oil (VOO) quality and antioxidant activity to date. The present study aimed to analyze the effects of PEF on oil yield, quality, and in vitro antioxidant activity of “Koroneiki” extra virgin olive oil. The results show that the PEF treatment increased the oil yield by 5.6%, but had no significant effect on the saponification value, K232, K270, and ∆K value of the VOO. PEF treatment reduced the oleic acid content by 3.12%, but had no significant effect on the content of palmitic acid, linoleic acid, linolenic acid, arachidonic acid, stearic acid, oleic acid, and palmitic acid. After PEF treatment, the levels of total phenolics, total flavonoids, and oleuropein increased by 7.6%, 18.3% and 76%, respectively. There was no significant effect on the levels of 4 phenolic acids (vanillic acid, p-coumaric acid, ferulic acid and cinnamic acid), 2 lignans (lignans and apigenin), hydroxytyrosol, and 3 pigments (lutein, demagnetized chlorophyll, and carotenoids). In addition, PEF treatment significantly increased the content of tocopherols, with α, β, γ, and δ tocopherols increasing by 9.8%, 10.7%, 13.6% and 38.4%, respectively. The free radical scavenging ability of DPPH and ABTS was also improved. In conclusion, the use of PEF significantly increased the yield of VOO oil as well as the levels of total phenolics, total flavonoids, oleuropein, tocopherol, and in vitro antioxidant activity.

Effect of edapho-climatic conditions on fruit productivity, yield and olive oil quality in olive orchards (Olea europaea L.): case of a semi-arid region

The objective of the present work is to evaluate the relationship between the edapho-climatic conditions of the cultivation environment and the variability of olive productivity, yield, and quality of olive oil in orchards of the Moroccan Picholine (PM) population variety (Olea europaea L.). This work was carried out on different agricultural territorial units (agroecosystems) of the Beni Mellal-Khenifra region with a semi-arid climate during four agricultural seasons (2016/2017 to 2019/2020). For this purpose, the relevant agronomic and agro-biochemical parameters were studied, namely the stage of maturity, fruit and olive oil yields and quality indices. The data treatments of the results were performed according to descriptive and affiliated statistics by analysis of variance (ANOVA). We have found significant correlations (according to Pearson's R) between agroecosystems, particularly for weight of crude olives produced per hectare and temperature (R= 0.803), olive yield and humidity (R= 0.654), olive oil yield and temperature (R= 0.837), olive oil richness and humidity (R= -0.622), as well as the qualitative characteristics of the extracted oils, through the levels of free acidity and peroxide value (R = 0.467). These results confirm that in the studied semi-arid environments, the properties of the biotope of the cultivated olive groves, combined with the interannual agroclimatic variability, effectively influence the productivity of the olive trees, the oil production and the chemical and organoleptic quality of the extracted olive oil

Exogenous Applications of Kaolin and Glycine Betaine Increased the Yield and Quality of Olive Fruit and Olive Oil

Exogenous Applications of Kaolin and Glycine Betaine Increased the Yield and Quality of Olive Fruit and Olive Oil

Influence of Regulated Deficit Irrigation on Arbequina’s Crop Yield and EVOOs Quality and Sensory Profile

Regulated deficit irrigation in super-high-density (SHD) olive orchards is a well-known strategy to save water and control plant vigor, without decreasing fruit or oil yield. As there is controversial information about its influence on virgin olive oil quality, a trial was conducted in five SHD olive orchards of Arbequina cultivar in different locations of central, east, north and northeast Spain under full irrigation (FI) and regulated deficit irrigation (RDI) treatments. RDI applied during phase II of fruit growing (40% of total needs) saves more than 20% of water on average, without reductions in olive fruit or extra virgin olive oil (EVOO) yield. No threshold of 3.5 MPa of stem water potential was crossed in any case. RDI modified sterols and the fatty acid profile of EVOOs but not phenols, quality parameters, or the sensory profile. Latitude, altitude, and yearly rainfall have a big impact on some compounds such as campesterol, oleuropein, or margaroleic or linolenic acids.

Pulsed electric field increases the extraction yield of extra virgin olive oil without loss of its biological properties.

Pulsed electric field (PEF) has been used for improving extraction of extra virgin olive oil (EVOO). However, the biological changes induced by the consumption of pulsed electric field-obtained extra virgin olive oil (PEFEVOO) have not been studied yet. EVOO oils from Empeltre variety were prepared by standard (STD) cold pressure method involving crushing of the olives, malaxation and decanting and by this procedure including an additional step of PEF treatment. Chemical analyses of EVOO oils were done. Male and female Apoe-deficient mice received diets differing in both EVOOs for 12 weeks, and their plasma, aortas and livers were analyzed. PEF application resulted in a 17% increase in the oil yield and minimal changes in chemical composition regarding phytosterols, phenolic compounds and microRNA. Only in females mice consuming PEF EVOO, a decreased plasma total cholesterol was observed, without significant changes in atherosclerosis and liver steatosis. PEF technology applied to EVOO extraction maintains the EVOO quality and improves the oil yield. The equivalent biological effects in atherosclerosis and fatty liver disease of PEF-obtained EVOO further support its safe use as a food.

Effect of Regulated Deficit Irrigation on the Quality of ‘Arbequina’ Extra Virgin Olive Oil Produced on a Super-High-Intensive Orchard

The expansion of the super-high-intensive cultivation of olive groves requires irrigation techniques that are compatible with the increasing scarcity of water due to climate change and olive oil demand. For this, the effect of two regulated deficit irrigation treatments (RDI) and a sustained deficit irrigation (SDI) treatment was studied. The treatments consisted of: (i) control treatment, which supplied 100% of the water lost by evapotranspiration (ET0); (ii) the “optimal RDI” treatment, which only reduced irrigation water (~37–54% reduction) during the pit hardening stage; (iii) the “confederation RDI” which limited water restriction to the donation of the Guadalquivir hydrographic confederation (~72% reduction); and, (iv) the “confederation SDI”, similar water restriction (~72%) but dying the whole tree cycle. In general, the reduction in the irrigation water caused no negative effects on the studied parameters. However, the total phenolic content (TPC) was increased when the deficit irrigation was applied. Fatty acid profile showed changes with respect to the control, increasing oleic acid and the total content of monounsaturated fatty acids (MUFA). For the volatile compound profile, reducing water intake caused changes in mayor volatile compound (trans-2-hexenal), related with green flavors. The application of deficit irrigation treatments increased the value obtained in the fruity parameter with respect to the control. On the other hand, irrigation deficit treatments did not generate changes in the olive oil yield.

Zeolites and Biochar Modulate Olive Fruit and Oil Polyphenolic Profile.

Soil degradation processes and climate change threaten the sustainability of Mediterranean rainfed olive orchards, with repercussions on crop yield and quality of olives, olive oil and olive by-products. Using soil amendments can enhance soil fertility for sustained environmental quality and plant performance. For two years, we evaluated, under rainfed conditions, the effects of a fertilizer compound (FC) and its combination with zeolites (ZL) and biochar (BC) amendments on soil moisture, yield, fruit and oil polyphenols and quality indices. The polyphenolic composition was strongly influenced by treatments, although no effects were observed on crop yield. ZL improved soil moisture (average increase of 26.3% compared to FC), fruit fatty acid composition (increase of 12.4% in oleic/linoleic ratio in 2018) and oil quality, BC enhanced the concentrations of polyphenols with high nutritional value (average annual increase of 25.6, 84.8 and 11.6% for 3,4-dihydroxyphenylglycol, oleuropein and rutin, respectively). In contrast, olive oil from FC fruits showed the poorest quality, with oxidation and hydrolytic breakdown signals. The applied soil amendments appear to be a promising sustainable strategy to implement in olive rainfed orchards.

Life cycle assessment of the most representative virgin olive oil production systems in Tunisia

This study aims to analyze the environmental impacts of Tunisian olive oil production using a “cradle to gate” Life Cycle Assessment (LCA) in order to quantify, compare and establish the most environmentally sustainable practices. This is the first LCA study in Tunisia that covers together the agricultural and industrial activities of one of their most important product value chains. This analysis considers the main olive grove cultivation systems in Tunisia (extensive, intensive, and super intensive) as well as the main extraction systems (press, 3-phase and 2–3 phase combined system). Sixteen categories of environmental impact were assessed following the guidelines set down by the “Product Environmental Footprint Category Rules” for olive oil established by the European Commission. Through the results obtained, it is possible to identify which is the most impactful of the main types of cultivation and extraction systems considered for every impact category individually. As representative values, the impact in climate change category for the most representative value chain (extensive crops and 3 phase extraction) is 3.29 kg CO 2 eq. per kg of olive oil without considering biogenic C and 3.53 kg CO 2 eq. if biogenic C is considered. The study determines that agricultural activities represent the heaviest contribution in all impact categories for the most representative value chain (from 84.7 % in photochemical ozone formation to 99.9 % in land use). Therefore, efforts should be focused on reducing the impact of the agricultural stage and reaching a high olive oil yield to reduce the overall environmental impact. For that reason, the study proposes to improve efficiency in the agricultural field and continue the investments in the presence of the 2–3 phase combined system.

Impact of drought and salinity on olive potential yield, oil and fruit qualities (cv. Chemlali) in an arid climate

The increase water demand for irrigation is leading to the use of low-quality water resources. The combined impact of drought and salinity on olive production sustainability, yield quality, growth, soil salinity and soil water conditions in arid areas has been little investigated. This study’s purpose was conducted to investigate the effects of the monitoring of saline water irrigation on soil properties and olive trees (cv. Chemlali) grown in an arid region of Tunisia (Sfax), on the potential yield, growth and quality of the resultant virgin olive oil in comparison to Rain-fed conditions. It is also intended to compare olive productive performance during a severe drought with, and without, irrigation and to assess recovering capacities after long driest period. Three irrigation levels were considered: (i) Full irrigation (100%ETc) with saline water 7.5 dS m-1 (FI); (ii) Full irrigation with same amount of water than the FI applied with tap water 2.46 dS m-1 (TW); and (iii) Rain-fed conditions (Dry). The results have showed that irrigation with saline water maintained the soils permeability, induced the distribution of salts outside the root zone. Additionally, it has maintained an adequate hydration of the rhizosphere through continuous and efficient leaching of salts to deep horizons. After drought period, the increase of the yield of rain-fed trees indicated 50% of recovery as compared to saline water. Irrigation with saline water reduced this gap due to drought impact. But it was 50% under that tap water; while reduction was 15% as a reduction capacity of potential yield. Hence, drought and salt stress alter the olive tree capacity and potential yield in an irreversible way if their severity is very intense. As salinity increased, there was a desirable sink in measured total phenols and flavonoids levels and a rise of oleic and linoleic acids as compared to rainfed conditions. For the triglycerides composition, triolein (OOO) was present in very large quantity in three oils, with a high content for FI (23.94%). Saline water treatment did not affect free acidity, peroxide value, K232, K270, chlorophyll, carotenoids, in contrast to Rain-fed treatment which was decreased. Olive trees permanently lost less than half of their potential yield during drought without irrigation. Irrigation with saline water seems to ensure sustainable monitoring olive yield and oil quality.

Protecting Superfood Olive Crop from Pests and Pathogens Using Image Processing Techniques: A Review

Background: Olive (Oleo europaea L.) cultivars are widely cultivated all over the world. However, they are often attacked by pests and pathogens. This deteriorates the quality of the crop, leading to less yield of olive oil. The different infections that cause comparable disease symptoms on olive leaves can be classified using image processing techniques. Objective: The olive has established itself as a superfood and a possible source of medicine, owing to the rapid increase in the availability of data in the field of nutrigenomics. The goal of this review is to underline the importance of applying image processing techniques to detect and classify diseases early. Method: PubMed, ScienceDirect, and Google Scholar were used to conduct a systematic literature search using the keywords olive oil, pest and pathogen of olives, and metabolic profiling. Results: Infections caused by infectious diseases frequently result in significant losses and lowquality olive oil yields. Early detection of disease infestations can safeguard the olive plant and its yield. Results: This strategy can help protect the crop from disease spread, and early detection and classification of the disease can aid in prompt prophylaxis of diseased olive plants before the disease worsens. Protecting olive plants from pests and pathogens can help keep the yield and quality of olive oil consistent.

Response of olive (Olea europaea L.) trees to foliar spray of nano chelated and chemical potassium fertilizers

Global challenges resulting from increased population and increased use of water and soil resources encourage researchers to focus on new compounds, such as nano-fertilizers. Hence, the present study aims to find out and compare the impact of foliar spray of two potassium (K) sources with the different formula, i.e. nano-chelated potassium and potassium nitrate, on olive oil yield and content over two successive years (2017–2018). During the bud-swelling stage, before blooming, the pit hardening stage, and shortly after the harvest of table olive, the fertilizers are used at the concentration of 1.84 (K1) and 2.45 (K2) g potassium nitrate, 3 (nano-K1) and 4 (nano-K2) g potassium nano-chelated, corresponding to 0.81 g (K1 and nano-K1) and 1.08 g (K2 and nano-K2) pure potassium per liter. The results show that fruit yield and characteristics are affected by k2 foliar application. High oil percentage is achieved by k1, which results in a low crop load and the highest leaf carbohydrate content in August. Traits, such as total phenol compound and antioxidant capacity of oil, are strongly enhanced under nano-K1 fertilizer, but quality characteristics of olive oil are relatively affected. Furthermore, nano-K1 treatment can positively affect fatty acid composition through the improvement of leaf mineral content rather than controlling tree. According to the results, fruit yield and traits are better under potassium nitrate (K2) treatment, and the quality of olive oil is more stable after nano-chelate potassium (nano-K1) foliar application.

Optimization of Virgin Olive Oil Yield and Quality Applying Nonthermal Processing

Optimization of Virgin Olive Oil Yield and Quality Applying Nonthermal Processing

Use of Enzymatic Preparations to Improve the Productivity and Quality of Olive Oil

Improving the quantity and quality of olive oil extraction is considered crucial for producers not only in Jordan but also worldwide. The present study aimed to enhance olive oil yield from olive fruits without compromising its quality by applying an enzymatic treatment technique during the malaxation stage of the oil extraction process.
 The enzymes that were used in this study were cellulase, pectinase, and a mixture of both enzymes at a ratio of (1:1). Each of the enzymes and there mixture was added at concentrations of 0.02 %, 0.04 % 0.06 %, 0.08 %, 0.10 %, and 0.12 % (w/w). Two Jordanian olive cultivars, Nabali Baladi (NB) and Nabali Muhassan (NM), in their immature state, were selected for the enzymatic treatment. The olive oil yield increased significantly (P < 0.05) after the enzymatic treatment. The increments in yield were 4.38 % (at an enzymatic concentration of 0.08 %), 3.29 % (at 0.1 %), and 5.25% (at 0.12 %) for NB treated with cellulase, pectinase, and 1:1 cellulase/pectinase, respectively. The increments in oil yield were 4.08 % (at 0.1%), 3.09 % (at 0.12%), and 4.5 (at 0.08%) for NM treated with cellulase, pectinase, and 1:1 cellulase/pectinase, respectively. The percent increments were significantly (P < 0.05) higher for NB than for NM. The quality parameters in terms of acidity, peroxide values, and UV-extinction coefficients at 232 and 270 nm were not significantly affected in any of the treatment groups when compared to those of control samples. The content of phenolic compounds, α-tocopherols, chlorophylls, and carotene was significantly higher (P < 0.05) in both oils in all enzymatic treatments than in the control, resulting in increased oxidative stability, as revealed by Rancimat analyses.

Tree Planting Density and Canopy Position Affect ‘Cerasuola’ and ‘Koroneiki’ Olive Oil Quality

To maximize orchard production and tree crop efficiency, optimization of both maximum orchard light interception and radiation distribution within the tree canopy are important strategies. To study the influence of planting density and fruit position within the canopy on oil quality from ‘Cerasuola’ and ‘Koroneiki’ olive (Olea europaea L.), fruits were harvested from the upper and lower canopy layers of trees in hedgerow planting systems at two densities: High at 1000 trees ha−1 (HD) and Medium at 500 trees ha−1 (MD). Tree crop efficiency and fruit weight, water and fat content were measured together with olive oil standard quality parameters, phenolic and volatile composition. Fruits in the upper layers of the canopy always showed a higher maturity index, 6% more fat content, and 4% less water content than lower layers. Upper layers of HD trees showed the highest phenol content, whereas lower layers of MD trees showed the lowest phenol content (36% less than the upper layers of HD). HD trees showed the largest differences in fruit maturation, water and fat content between upper and lower canopy positions, increasing quality and oil yield variability at harvest. ‘Koroneiki’ showed more stable oils with a 28% higher MUFA/PUFA ratio and 12% higher phenol content than ‘Cerasuola’ oils. This study provides further evidence of the fact that cultivar, planting density, and canopy architecture may be strong determinants of olive oil yield and composition in hedgerow planting systems.

Life cycle assessment of the Spanish virgin olive oil production: A case study for Andalusian region

Abstract Spain is the first olive oil producer worldwide (representing around 45%), with more than 80% of its agricultural area dedicated to this crop. The goal of this study is to assess the environmental impact of the Spanish virgin olive oil production, attending to the farming and industrial phases. A Life Cycle Assessment (LCA) is conducted for 5 harvests in approximately 4.000 ha of olive grove in Jaen, the largest producer region of Spain. The type of farming is the most representative in Spain: conventional (non-organic), with a medium-low slope, extensive (100–150 trees per ha) and around 60% dryland orchards. The industrial phase is based on 2-phase extraction process and olive pomace valorization. The functional unit (FU) chosen for the comparative analysis is 1 kg of unpacked virgin olive oil under a perspective from “cradle to gate”. One of the most representative categories, climate change, places the average environmental impact in 2.43 kg CO2 eq/kg, while the range is between 1.93 and 3.00 kg CO2 eq/kg depending on the harvest. Huge differences between values are observed in the farming phase and they are mostly caused by the virgin olive oil yield of every harvest. The carbon sequestration analyses and the impact produced per FU ranges from 43.78% (for 15/16 harvest) to 46.36% (for 17/18). The impact hotspots detected in the farming phase, in terms of climate change potential, are the categories of plant protection products and herbicides (24.11% of the average value) and fertilizers (20.01%). However, the environmental impact of the industrial phase is relatively constant, with a value of 0.547–0.554 kg of CO2 equivalent. The 80.74% is caused by pomace valorization, which translated to the average whole value, represents the 18.56%.

Partial De‐Stoning of Olive Paste to Increase Olive Oil Quality, Yield, and Sustainability of the Olive Oil Extraction Process

AbstractStone recovery in the olive oil extraction process can be an opportunity to increase both incomes and environmental sustainability. To this aim a new partial de‐stoning machine (called Moliden) is installed at the first stage of an olive oil extraction plant to investigate its influence on the quality and sustainability of the extraction process. Quantitative and qualitative results are compared with those achieved using a conventional extraction process. Despite the 60% of stone recovered, no significant differences are registered for oil yield and extractability. A high‐quality biomass is recovered by the partial de‐stoner machine, belonging to A1 class quality when compared to the standard of the wood pellet, with the only exception of the moisture content. The partial de‐stoning also improves the extra virgin olive oil (EVOO) quality in terms of hydrophilic phenols resulting in an enhancement of bitter and pungent sensory notes and most of all provides a beneficial effect for human health.Practical Applications: The new concept of partial de‐stoner machine proposed in this work allows reducing the equipment employed in the extraction process of olive oil, since it consists of two sections: crushing and de‐stoning. When compared with a standard unit, which recover pits from pomace, it provides a higher quality stone to be used as a biomass fuel. This leads to economic benefits for the millers and has a significant impact on the environmental sustainability of the process.

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

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). 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. Calcium foliar applications during fruit development effectively increase olive quality. © 2020 Society of Chemical Industry.