Factors affecting olive oil quality

Olive (Olea europaea, Z.), an evergreen tree has been cultivated for thousands years, in many semi-arid and arid mountainous areas surrounding the Mediterranean Sea. Olive oil is extracted from the olive fruit by mechanical means, without any chemical treatment thus preserving all of its natural constituents, which are responsible for the unique flavor, as appreciated by consumers. This thesis concentrates on the important factors that might affect the quality of olive oil. These comprise: cultivar / agricultural methods / weather / processing / storage. Of the quantitative and qualitative results obtained, the following are of particular interest. The olive variety influenced the chemical composition and sensory quality of the olive oil. Particularly affected were the composition of fatty acids, sterols, aliphatic and triterpene alcohols, phenolic compounds and sensory attributes. Osmotic stress, due to no irrigation or to saline irrigation, influenced the size and oil content of the fruit and the composition of triacylglycerol molecular species, fatty acids, total phenols, secoiridoid derivatives as well as volatile compounds and sensory attributes of olive oil The processing methods affected the sensory quality and the phenolic compounds of olive oil. The most significant variations occured mainly due to the quantity of water added to the system of extraction and the duration and temperature of malaxation. The alteration of these during the extraction process was reflected in oxidative processes. The rate of olive oil oxidation was a function of both the time and the various conditions of storage. Virgin olive oil keeps its qualitative characteristics under the category of extra virgin olive oil for 15 months if it is stored in tin containers indoors at room temperature and with nitrogen in the headspace. The present studies provide information for the olive oil industry in order to improve the overall olive oil quality by optimising each step of the production chain.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Factors affecting olive oil quality

Olive (Olea europaea, Z.), an evergreen tree has been cultivated for thousands years, in many semi-arid and arid mountainous areas surrounding the Mediterranean Sea. Olive oil is extracted from the olive fruit by mechanical means, without any chemical treatment thus preserving all of its natural constituents, which are responsible for the unique flavor, as appreciated by consumers. This thesis concentrates on the important factors that might affect the quality of olive oil. These comprise: cultivar / agricultural methods / weather / processing / storage. Of the quantitative and qualitative results obtained, the following are of particular interest. The olive variety influenced the chemical composition and sensory quality of the olive oil. Particularly affected were the composition of fatty acids, sterols, aliphatic and triterpene alcohols, phenolic compounds and sensory attributes. Osmotic stress, due to no irrigation or to saline irrigation, influenced the size and oil content of the fruit and the composition of triacylglycerol molecular species, fatty acids, total phenols, secoiridoid derivatives as well as volatile compounds and sensory attributes of olive oil The processing methods affected the sensory quality and the phenolic compounds of olive oil. The most significant variations occured mainly due to the quantity of water added to the system of extraction and the duration and temperature of malaxation. The alteration of these during the extraction process was reflected in oxidative processes. The rate of olive oil oxidation was a function of both the time and the various conditions of storage. Virgin olive oil keeps its qualitative characteristics under the category of extra virgin olive oil for 15 months if it is stored in tin containers indoors at room temperature and with nitrogen in the headspace. The present studies provide information for the olive oil industry in order to improve the overall olive oil quality by optimising each step of the production chain

Reciprocal translocation t(2;12)(q31;p13) in a case of CMML

Case report of a translocation : Reciprocal translocation t(2;12)(q31;p13) in a case of CMML

Influencia del estrés hídrico sobre la calidad del aceite de oliva en la variedad Koroneiki

Quality characteristics (acidity, peroxide values, K232, K270, oxidative stability) and chemical compositional data (fatty acids, sterols and triacylglycerols) were studied in virgin olive oil samples from olive trees, cv Koroneiki, subjected to different water regimes. Experimental trials were carried out using three-year old own-rooted olive trees (Olea europaea L) variety Koroneiki. Plants were subjected to two irrigation treatments to maintain soil water potential to -0.03 MPa and -1.5 MPa. Results showed that irrigation significantly increased the fruit oil content and the oxidative stability and peroxide value of the resulting oil. Olive oil from fruits of irrigated trees showed significant higher values in total saturated fatty acids. Total sterols were also significantly influenced by irrigation. Acidity and specific absorption coefficients K232, K270, of olive oils were not significantly affected.Se han estudiado los valores de calidad reglamentada (acidez, índice de peróxido, los valores de absorbancia en UV (K270, K232), estabilidad oxidativa media en Rancimat 120ºC) y características químicas (ácidos grasos, esteroles, triglicéridos) en aceite de oliva virgen variedad Koroneiki sometidos a diferentes regímenes hídricos. El estudio se ha realizado en árboles adultos de 3 años cultivados en contenedor al aire libre. Los árboles se riegan con dos dosis tratando de mantener un potencial de agua en el suelo de unos -0,03 Mpa y -1,5 Mpa. Los resultados muestran en los olivos de riego un aumento significativo de la riqueza grasa y de la estabilidad del aceite. Los aceites producidos en olivos de riego presentan una mayor proporción de ácidos grasos saturados (palmítico-esteárico). Los esteroles totales se ven significativamente influenciados por el riego. Acidez y absorbancia K270, K232 no se han visto afectados por el riego

Chemical properties of virgin olive oil from Iranian cultivars grown in the Fadak and Gilvan regions

The aim of this study is to evaluate the chemical compositions (total phenol, fatty acid, sterolic compounds) of Iranian virgin olive oil (Zard, Rowghani, Mari) cultivated in the Gilvan (Zanjan Province) and Fadak (Qom Province) regions. Total phenols were determined using the Folin-Ciocalteu assay. Fatty acid and sterol profiles were also analyzed using gas chromatography. In most cases, significant effects (<em>P</em> < 0.05) of cultivars and locations were detected by the chemical composition of the oil samples. The fatty acid analysis indicated that the Mari variety from Gilvan had high oleic/low linoleic acid content; therefore it is a highly resistant olive oil against oxidation. Furthermore, the high mean values of total sterols were also obtained for the Mari variety. The oil of the Zard variety from Gilvan had the maximum amount of phenols as a positive quality index. Therefore, the Mari variety, especially from Gilvan has been suggested as a superior cultivar compared to the Zard and Rowghani varieties.<br><br>El objetivo de este estudio fue evaluar la composición química (fenoles totales, ácidos grasos, y esteroles) de aceites de oliva virgen iranies (Zard, Rowghani, Mari) cultivados en las regions de Gilvan (provincia de Zanjan) y Fadak (provincia de Qom). Los fenoles totales se determinaron utilizando el método de Folin-Ciocalteu. Los perfiles de ácidos grasos y de esteroles se determinaron mediante cromatografía de gases. En la mayoría de los casos, existen diferencias significativos de los cultivares y los lugares detectados por la composición química (P < 0,05 ). El análisis de ácidos grasos indicó que la variedad Mari de Gilvan presenta una relación alta oleico/ linoleico; por lo tanto, es un aceite de alta resistencia contra la oxidación. Por otra parte, los valores medios altos de esteroles totales también fueron obtenidos para la variedad Mari. El aceite de la variedad Zard de Gilvan presentó la mayor cantidad de fenoles, considerado este valor como un índice de calidad positivo. La variedad Mari especialmente en Gilvan se sugeriere como un cultivar superior en comparación con las variedades Zard y Rowghani

Diversity for olive oil composition in a collection of varieties from the region of Valencia (Spain)

Olive (Olea europaea) has a long history of cultivation in the Mediterranean region of Valencia (Spain) and many local varieties exist in the area. According to their economic importance, varieties are classified as National, Principal, Secondary, Local, Disseminate, and Minor. We have evaluated during four seasons the olive paste moisture content, fat content, and olive yield, and the olive oil acidity, peroxide index, K232 and K270 parameters, total phenolics, K225 parameter, and fatty acids content in 45 varieties from the Collection of Olive Varieties from the Region of Valencia. Considerable diversity existed among varieties for all traits studied, and the variety effect was much greater than the season effect. Wide ranges of variation have been found for most traits, with differences among varieties being of more than 10-fold for total phenolics. The coefficient of genetic variation and heritability values have been generally high, in particular for fatty acids content. A few varieties were found to present values outside the ranges established in the regulations for several olive oil composition traits, although in some cases, like a variety with above the limit content of oleic acid, they are of interest for breeding. Several correlations were found to be significant between the K232 index and fatty acids profile, in particular with oleic acid. The values obtained for variety averages as well as the principal components analysis show that economically relevant varieties present a lower diversity for composition than varieties with low economic importance. In this respect, selection among traditional materials can be of interest to recover neglected varieties with specific composition profiles, as well as to identify sources of variation for breeding programmes. Discriminant analysis allowed a correct classification of 99.4% of samples, showing that composition profiles, in particular fatty acids content, is a powerful tool for chemometry and fingerprinting of olive oil. Overall, the results show that the wide diversity found in the collection studied, in particular in the less economically important varieties, is of interest for the selection and breeding of olive varieties with improved quality.Authors are grateful to Sergio Paz (Instituto Valenciano de Investigaciones Agrarias, Moncada, Spain) for his technical help, and also to the Laboratorio Agroalimentario de la Conselleria de Agricultura, Pesca, Alimentacion y Agua of the Generalitat Valenciana for the providing the facilities and funds for this research.Ruiz Dominguez, ML.; Raigón Jiménez, MD.; Prohens Tomás, J. (2013). Diversity for olive oil composition in a collection of varieties from the region of Valencia (Spain). Food Research International. 54(2):1941-1949. doi:10.1016/j.foodres.2013.06.023S1941194954

Irrigation and fruit canopy position modify oil quality of olive trees (cv. Frantoio)

BACKGROUND: Fruit development and oil quality in Olea europaea L. are strongly influenced by both light andwater availability. In the present study, the simultaneous effects of light environment and irrigation on fruit characteristics and oil quality were studied in a high-density orchard over two consecutive years. Olive fruits were harvested from three canopy positions (intercepting approximately 64%, 42% and 30% of above canopy radiation) of fully-productive trees subjected to full, deficit or complementary irrigation. RESULTS: Fruits receiving 61–67% of above canopy radiation showed the highest fruit weight, mesocarp oil content and maturation index, whereas those intercepting only 27–33% showed the lowest values. Palmitoleic and linoleic acids increased in oils obtained from fruits exposed to high light levels, whereas oleic acid and the oleic-linoleic acid ratio decreased. Neither canopy position, nor irrigation affected K232, K270, K and the concentration of lignan in virgin olive oils (VOOs). Total phenols, 3,4-DHPEA-EDA [2-(3,4-hydroxyphenyl)ethyl (3S,4E)-4-formyl-3-(2-oxoethyl)hex-4-enoate] and p-HPEA-EDA (decarboxymethyl ligstroside-aglycone) increased in VOOs produced from fruits harvested from the top of the canopy, whereas full irrigation decreased total phenols and 3,4-DHPEA-EDA concentrations with respect to the complementary irrigation treatment. CONCLUSION: Light and water availability are crucial not only for tree productivity, but also they clearly affect olive oil quality. © 2017 Society of Chemical Industr

Evaluation of extra-virgin olive oils shelf life using an electronic tongue-chemometric approach

Physicochemical quality parameters, olfactory and gustatoryretronasal positive sensations of extra-virgin olive oils vary during storage leading to a decrease in the overall quality. Olive oil quality decline may prevent the compliance of olive oil quality with labeling and significantly reduce shelf life, resulting in important economic losses and negatively condition the consumer confidence. The feasibility of applying an electronic tongue to assess olive oils usual commercial light storage conditions and storage time was evaluated and compared with the discrimination potential of physicochemical or positive olfactory/gustatory sensorial parameters. Linear discriminant models, based on subsets of 58 electronic tongue sensor signals, selected by the meta-heuristic simulated annealing variable selection algorithm, allowed the correct classification of olive oils according to the light exposition conditions and/or storage time (sensitivities and specificities for leave-one-out cross-validation: 8296 %). The predictive performance of the E-tongue approach was further evaluated using an external independent dataset selected using the KennardStone algorithm and, in general, better classification rates (sensitivities and specificities for external dataset: 67100 %) were obtained compared to those achieved using physicochemical or sensorial data. So, the work carried out is a proof-of-principle that the proposed electrochemical device could be a practical and versatile tool for, in a single and fast electrochemical assay, successfully discriminate olive oils with different storage times and/or exposed to different light conditions.The authors acknowledge the financial support from the strategic funding of UID/BIO/04469/2013 unit, from Project POCI-01-0145-FEDER-006984—Associate Laboratory LSRELCM funded by FEDER funds through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI)—and by national funds through FCT—Fundação para a Ciência e a Tecnologia and under the strategic funding of UID/BIO/04469/2013 unit. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/BD/104038/2014).info:eu-repo/semantics/publishedVersio

Differential scanning calorimetric analysis of edible oils: comparison of thermal properties and chemical composition

The thermal profiles of 17 edible oil samples from different plant origins were examined by differential scanning calorimetry (DSC). Two other confirmatory analytical techniques, namely gas-liquid chromatography (GLC) and high-performance liquid chromatography (HPLC), were used to determine fatty acid (FA) and triacylglycerol (TAG) compositions. The FA and TAG compositions were used to complement the DSC data. Iodine value (IV) analysis was carried out to measure the degree of unsaturation in these oil samples. The DSC melting and crystallization curves of the oil samples are reported. The contrasting DSC thermal curves provide a way of distinguishing among these oil samples. Generally, the oil samples with a high degree of saturation (IV65). Each thermal curve was used to determine three DSC parameters, namely, onset temperature (T o ), offset temperature (T f ) and temperature range (difference between T o and T f ). Reproducibility of DSC curves was evaluated based on these parameters. Satisfactory reproducibility was achieved for quantitation of these DSC parameters. The results show that T o of the crystallization curve and T f of the melting curve differed significantly (P<0.01) in all oil samples. Our observations strengthen the premise that DSC is an efficient and accurate method for characterizing edible oils