The effect of water stress on super-high- density 'Koroneiki' olive oil quality

Effect of macronutrient fertilization on olive oil composition and quality under irrigated, intensive cultivation management

BACKGROUND

Intensive olive (Olea europaea L.) orchards are fertilized, mostly with the macronutrients nitrogen (N), phosphorus (P) and potassium (K). The effects of different application levels of these nutrients on olive oil composition and quality were studied over 6 years in a commercial intensively cultivated 'Barnea' olive orchard in Israel.

RESULTS

Oil quality and composition were affected by N, but not P or K availability. Elevated N levels increased free fatty acid content and reduced polyphenol level in the oil. Peroxide value was not affected by N, P or K levels. The relative concentrations of palmitoleic, linoleic and linolenic fatty acids increased with increasing levels of N application, whereas that of oleic acid, monounsaturated-to-polyunsaturated fatty acid ratio and oleic-to-linoleic ratio decreased.

CONCLUSION

These results indicate that intensive olive orchard fertilization should be carried out carefully, especially where N application is concerned, to avoid a decrease in oil quality due to over-fertilization. Informed application of macronutrients requires leaf and fruit analyses to establish good agricultural practices, especially in view of the expansion of olive cultivation to new agricultural regions and soils. © 2022 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Changes in Quality and Antioxidant Properties of Virgin Olive Oil of 'Cornicabra' According to Fruit Maturation in Longnan, China

This work aims to study the influence of olive fruit maturity on physicochemical properties and antioxidant activity which determine the quality of virgin olive oils (VOO). According to the results, the values of all parameters were within the range specified by the Codex Alimentarius (2017). With the increase of fruit maturity, the oil content continued to increase until reached the maximum value (20.05%) in the 7th maturity (M7). K₂₃₂, K₂₇₀ and peroxide value (PV) decreased with the increase of maturity, while ΔK increased linearly with the increase of maturity. Free fatty acidity (FFA) first decreased and then increased, until reached the maximum value of (0.52 ± 0.03) % in M7. The total polyphenols (TP) and total flavonoids (TF) that characterized the antioxidant properties of olive oil increased with the increase of fruit maturity, which indicated that the oxidative stability (OS) of VOO of 'Cornicabra' increased with the increase of fruit maturity. The oleic acid (C18:1) content remained above 70 % and reached the maximum of (76.68 ± 0.17) % at M7. The values of monounsaturated fatty acids (MUFA) / polyunsaturated fatty acids (PUFA) and oleic acid (C18:1) / linoleic acid (C18:2) showed a decreasing trend with the maturity stage. Principal component analysis (PCA) showed that the quality of FFA, PV, K₂₃₂, K₂₇₀, TP, TF and OS were higher at the 5th maturity (M5), the quality of fatty acid were higher at M7. It can be seen from the analysis that the olive fruit maturity was an important parameter to characterize and distinguish olive oil.

Characterization of virgin olive oils from Spanish olive varieties introduced in Mendoza, Argentina, and their comparison with the autochthonous variety

BACKGROUND

The aim of this work was to evaluate and compare oil production and its quality in three Spanish olive varieties (Genovesa, Villalonga, and Nevadillo blanco) growing outside the Mediterranean basin with the Argentine autochthonous variety (Arauco). Fruit parameters and oil characteristics were evaluated using samples collected from the germplasm collection of Mendoza province and elaborated in the same place.

RESULTS

The levels of phenolic compounds and the fatty acid composition of the samples were comparable with those previously published for these Spanish varieties, grown in the Mediterranean basin, showing the adaptability of olive trees. Observing the levels of phenolic compounds and oxidative stability, a strong correlation between oxidative stability and oleocanthal was observed.

CONCLUSION

The characteristics of the fruit and oil differed according to variety and season. The inter-harvest stability was different depending on the variety. Genovesa was observed to be the most stable variety according to its fruit and oil characteristics - even more stable than the autochthonous variety, Arauco. However, in terms of the composition of phenolic compounds, Arauco was the most stable between harvests, this characteristic being more important for the taste and uniformity of the product. © 2020 Society of Chemical Industry.

Olive oil varieties and ripening stages containing the antioxidants hydroxytyrosol and derivatives in compliance with EFSA health claim

Virgin olive oils (VOO) and extra virgin olive oils (EVOO) contain a specific fraction of polyphenols (hydroxytyrosol and its derivatives) that produce beneficial physiological effects. The European Food Safety Authority (EFSA) authorised a health claim for olive oil (OO) containing at least 250 mg/Kg of those polyphenols. The specific polyphenol content of twelve varieties of EVOO extracted at three different maturation stages was investigated. The total concentration of specific polyphenols changed depending on the olive oil variety. The varieties showing the highest specific polyphenol content (all above 250 mg/Kg) were Lechín Sevilla (429.5 ± 5), Manzanilla Sevilla (407.6 ± 6) and Cornezuelo (394.0 ± 6) in the green phase; Cornicabra (362.0 ± 8), Nevadillo Negro (326.5 ± 4) and Picual 296.0 ± 6) in the turning phase; and Lechin Granada (382.8 ± 4), Picual (317.7 ± 3), Lechin Sevilla (294.4 ± 5) and Manzanilla Sevilla (278.0 ± 2) in the mature phase. These results could have potential application for the industrial production of a category of healthy antioxidant OO.

High temperature environment reduces olive oil yield and quality

Global warming is predicted to have a negative effect on plant growth due to the damaging effect of high temperatures. In order to address the effect of high temperature environments on olive oil yield and quality, we compared its effect on the fruit development of five olive cultivars placed in a region noted for its high summer temperatures, with trees of the same cultivars placed in a region of relatively mild summers. We found that the effects of a high temperature environment are genotype dependent and in general, high temperatures during fruit development affected three important traits: fruit weight, oil concentration and oil quality. None of the tested cultivars exhibited complete heat stress tolerance. Final dry fruit weight at harvest of the 'Barnea' cultivar was not affected by the high temperature environment, whereas the 'Koroneiki', 'Coratina', 'Souri' and 'Picholine' cultivars exhibited decreased dry fruit weight at harvest in response to higher temperatures by 0.2, 1, 0.4 and 0.2 g respectively. The pattern of final oil concentration was also cultivar dependent, 'Barnea', 'Coratina' and 'Picholine' not being affected by the high temperature environment, whereas the 'Koroneiki' and 'Souri' cultivars showed a decreased dry fruit oil concentration at harvest under the same conditions by 15 and 8% respectively. Regarding the quality of oil produced, the 'Souri' cultivar proved more tolerant to a high temperature environment than any other of the cultivars analyzed in this study. These results suggest that different olive cultivars have developed a variety of mechanisms in dealing with high temperatures. Elucidation of the mechanism of each of these responses may open the way to development of a variety of olives broadly adapted to conditions of high temperatures.

Quality Attributes and Fatty Acid, Volatile and Sensory Profiles of "Arbequina" hydroSOStainable Olive Oil

The use of deficit irrigation techniques on olive orchards is the main trend aiming to optimize water savings while improving functional and sensory characteristics of oils from trees under deficit irrigation techniques. The brand hydroSOStainable has been defined for crops produced under water restriction conditions. HydroSOStainable olive oils obtained under two new regulated deficit irrigation and one sustained deficit irrigation treatments in "Arbequina" olive trees were evaluated by analyzing quality parameters, antioxidant activity, total phenol content, fatty acid profile, volatile compounds, and sensory descriptors. Results showed that some of these irrigation strategies improved the phenol content at "moderate" stress levels, slightly enriched the fatty acid profile (~3.5% increased oleic acid and simultaneously decreased saturated fatty acids), and increased some key volatile compounds and also several key sensory attributes. Therefore, hydroSOStainable olive oil may be more attractive to consumers as it is environmentally friendly, has a higher content of several bioactive compounds, and has improved sensory characteristics as compared to control (fully irrigated) oils.

Chemometric characterization of virgin olive oils of the two major Cypriot cultivars based on their fatty acid composition

The effects of the geographical region and the botanical origin of olive oils on the profile of fatty acids isolated from monovarietal virgin olive oils from Cyprus were investigated, in order to establish, for the first time, promising models for authentication and classification of monovarietal virgin olive oils produced on the island. The two dominant Cypriot olive cultivars, Cypriot (ladoelia), and Koroneiki (lianolia), were analyzed for fatty acid composition by GC/FID after preparation of Fatty Acid Methyl Esters from olive oil, using a cold esterification method. The data obtained were analyzed statistically using multivariate and univariate ANOVA, principal components analysis (PCA) and hierarchical cluster analysis. Results showed that the olive oils can be separated into two distinct groups using the FAME data bank obtained from 225 samples. Significant differences in the proportion of some variables such as polyunsaturated linoleic acid, and the ratio C18:1/C18:2 from oils of different varieties and geographical regions were detected. The ratios C18:1/C18:2 and MUFA/PUFA, as well SFA, ω-9 and PUFA showed the higher discriminant power based on the cultivar.