Quantitation of endogenous amount of ethanol, methanol and acetaldehyde in ripe fruits of different Spanish olive varieties.

BACKGROUND: The use of healthy olives and their good management along the production process are necessary to obtain the best quality virgin olive oils. One parameter related to the health of the olives is the content of fatty acid alkyl esters. Because these come from the esterification of C16 and C18 free fatty acids with short chain alcohols, the control of methanol, ethanol and acetaldehyde (precursor of ethanol) and their origin (endogenous or from fermentation) is essential. The present study reports the endogenous amount of these compounds in some of the main Spanish olive varieties. For their analyses, headspace solid phase micro-extraction was applied and, to ensure quantitation reliability, the matrix-matched technique was used to build the calibration lines. RESULTS: For healthy and mature olives, the contents of ethanol and methanol are much higher and vary within a wider range than those corresponding to acetaldehyde. Because olives were not directly analyzed but previously homogenized, there was no correlation between the olive size parameters and the contents of the compounds investigated. However, these contents are characteristic of each variety. When comparing healthy and unhealthy olives, significant differences were only observed for ethanol contents. CONCLUSION: Higher contents of short alcohols are not only the result of an unhealthy or poor state of the fruits, but also the variety. Therefore, because these alcohols are precursors of fatty acid alkyl esters, the maximum permissible content of the latter should not be set at a single value for all olive varieties. © 2020 Society of Chemical Industry.

Identification and Characterisation of Pseudomonas savastanoi pv. savastanoi as the Causal Agent of Olive Knot Disease in Croatian, Slovenian and Portuguese Olive (Olea europaea L.) Orchards.

Strains of Pseudomonas savastanoi pv. savastanoi (Pss), isolated from infected olive trees (Olea europaea L.) in three European countries (Croatia, Slovenia and Portugal) were identified and characterised according to their colony morphology, physiological and biochemical features. According to the LOPAT scheme, 38.6% of Pss isolates were grouped in the Ib cluster. The Portuguese Pss strains were fully consistent with the typical LOPAT profile for this bacterium. Conversely, most Slovenian Pss strains showed delayed oxidase activity, whilst Croatian Pss strains did not produce any fluorescent pigment when grown in vitro. For Pss molecular identification, both end-point and real-time PCR were used, as well as MALDI-TOF, which was additionally used for proteomic analysis and the subsequent species identification of a number of strains that showed deviations from expected LOPAT results. Pss was confirmed as a causal agent of olive knot disease in 46.6% of olive orchards screened. Overall, these data suggests a possible correlation of certain Pss features with the geographical origin and the ecological niche of Pss isolates.

Phenolic Compounds Profiling of Virgin Olive Oils from Different Varieties Cultivated in Mendoza, Argentina, by Using Liquid Chromatography-Mass Spectrometry.

The aim of this work was to achieve a preliminary characterization of the profile of the phenolic fraction of virgin olive oils (VOOs) from Maipú (Mendoza, Argentina). Thus, 25 commercial VOO samples from Arauco, Arbequina, Picual, Frantoio, Changlot, Empeltre, Nevadillo, Manzanilla, and Coratina (both monovarietals and blends) were analyzed using LC-ESI-QTOF MS and LC-ESI-IT MS for identification and quantification purposes, respectively. A rapid LC method (15 min) accomplished quantitative information about a total of 40 phenolic compounds, including secoiridoid derivatives, which have not been evaluated before in samples coming from the subregion so-called Maipú (Mendoza province, Argentina). The results make evident that olive oils coming from Mendoza can be considered as important sources of phenolic bioactive compounds, exhibiting similar phenolic compound levels to those shown by oils from other typical world production regions. Moreover, some distinctive features of the Arauco variety (Argentinean autochthonous variety) were pointed out; indeed, a correlation between flavonoids content and botanical variety was established herewith.

Chemometric study of Andalusian extra virgin olive oils Raman spectra: Qualitative and quantitative information.

Authentication of extra virgin olive oil (EVOO) is an important topic for olive oil industry. The fraudulent practices in this sector are a major problem affecting both producers and consumers. This study analyzes the capability of FT-Raman combined with chemometric treatments of prediction of the fatty acid contents (quantitative information), using gas chromatography as the reference technique, and classification of diverse EVOOs as a function of the harvest year, olive variety, geographical origin and Andalusian PDO (qualitative information). The optimal number of PLS components that summarizes the spectral information was introduced progressively. For the estimation of the fatty acid composition, the lowest error (both in fitting and prediction) corresponded to MUFA, followed by SAFA and PUFA though such errors were close to zero in all cases. As regards the qualitative variables, discriminant analysis allowed a correct classification of 94.3%, 84.0%, 89.0% and 86.6% of samples for harvest year, olive variety, geographical origin and PDO, respectively.

Olive mill wastewater microconstituents composition according to olive variety and extraction process.

Olive oil production yields a considerable amount of wastewater, a powerful pollutant that is currently discarded but could be considered as a potential source of valuable natural products due to its content in phenolic compounds and other natural antioxidants. The aim of this work was to explore the variability in olive mill wastewater composition from Algerian olive oil mills considering extraction processes (traditional discontinuous press vs 3-phases centrifugal system) and olive varieties (Azerraj, Sigoise, Chemlal). Whereas pH, dry or organic matter content didn't vary, there was a significant difference in ash content according to extraction process and olive variety. Carotenoid content was 2.2-fold higher with 3-phases than with press systems whereas tocopherol content was not significantly different. Among the phenolic compounds quantified, tyrosol was usually the most abundant whereas oleuropein concentrations were highly variable. Differences in phenolic compound concentrations were more pronounced between olive varieties than between processes.