Quality Parameters Of Olive Oil Research Articles

How clarification systems can affect virgin olive oil composition and quality at industrial scale

The effect of two different clarification systems, vertical centrifugal separator (VCS) with minimal water addition, and conical bottom settling tank (CBST), on virgin olive oil (VOO) composition and quality was studied at industrial scale for three crop years. In general, for the studied clarification systems, higher clarification values were reached for horizontal screw solid bowl (HSSB) oils with higher moisture and solid content. VCS showed higher clarification efficiency for HSSB oils with higher moisture and solid content. No notable differences were observed on the quality indices between evaluated clarification systems. Phenolic compounds showed a significant decrease when the HSSB oils were clarified by CBST. In general, a better sensory score was observed when the oils were clarified by VCS.Practical applications: The VCS with a minimal water addition could result a better option to produce VOO of improved quality, since is an efficient and quick operation that reduces the contact between oil and the remaining water and impurities content during the storage stage. This leads to prolong VOO shelf‐life and conservation of positive sensory notes, due to preservation of the quality indexes and minor components. Besides, this clarification system reduces the water consumption and generated wastewater regarding to conventional vertical centrifugation, and therefore can be considered more environmentally friendly.Effect of two different clarification systems (vertical centrifugal separator with minimal water addition and conical bottom settling tanks) on the virgin olive oil quality parameters, composition, and sensory characteristics.

Olive oil enrichment in phenolic compounds during malaxation in the presence of olive leaves or olive mill wastewater extracts

A combined study was performed to determine the effect of olive leaf aqueous extract (OLE), olive mill wastewater (OMWW) or water addition during the malaxation step on total phenolic content (TPC), antioxidant activity, virgin olive oil composition and quality parameters of olive oil. For these purposes, the Folin‐Ciocalteu assay, 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) assay, and HPLC‐ESI‐TOF/MS were employed. The experiments were carried out at semi‐industrial scale in a cold extraction olive oil mill using olives of Koroneiki cultivar. Olive oil produced by olive paste which was malaxed without adding water, OMWW, or OLE was employed as control. The use of OMWW and OLE allowed obtaining oils with higher significant TPC compared to that malaxed with water (146.2 and 151.8 vs. 132.8 μg Eq GAE/g oil, respectively). The antioxidant activity followed the same trend. The use of OMWW and OLE enabled an oil enrichment in oleuropein derivatives, especially in 3,4‐DHPEA‐EDA. Despite the fact that acidity and oxidation (K270 and K232 values) were higher in the aforementioned oils compared to the oil extracted with water, all values were under the European Union commission parameters for extra virgin olive oil (EVOO) denomination. However, only the oil extracted using OLE presented slightly higher fruity, bitter, and pungent positive attributes compared to the control and to the oil extracted with water, thus, making OLE a promising by‐product for improving olive oils.Practical applications: This research provides new insight for the improvement of olive oil extraction process in order to obtain high‐phenol EVOO which could be useful for the olive oil, nutraceuticals, and cosmeceuticals industries. Besides, this study could serve as a starting point for improving the olive oil production process, while reducing the impact of its by‐products.The addition of Olive mil wastewater (OMWW) and olive leaf extract during malaxation, allowed obtaining enriched oils with a higher content in total phenolics, and antioxidant activity compared to those obtained adding water. These enriched oils presentes higher quantities of oleuropein derivatives and specifically of 3,4‐DHPEA‐EDA.

Extraction of olive oil assisted by high-frequency ultrasound standing waves

High-frequency ultrasound standing waves (megasonics) have been demonstrated to enhance oil separation in the palm oil process at an industrial level. This work investigated the application of megasonics in the olive oil process on laboratory and pilot scale levels. Sound pressure level and cavitational yield distribution were characterised with hydrophones and luminol to determine associated physical and sonochemical effects inside the reactor. The effect of water addition (0%, 15%, and 30%), megasonic power levels (0%, 50%, and 100%), and malaxation time (10min, 30min, and 50min) was evaluated using response surface methodology (RSM) in a 700g batch extraction process. The RSM showed that the effect of the megasonic treatment (585kHz) in the presence of a reflector is more prominent at longer malaxation time (50min) and at higher water addition (30%) levels post-malaxation. Longer megasonic treatment of the malaxed paste (up to 15min; 220kJ/kg) increased oil extractability by up to 3.2%. When treating the malaxed paste with the same specific energy, higher oil extractability was obtained with longer treatments and low megasonic power levels in comparison to higher power levels and shorter times. Megasonic treatment of the paste before malaxation (585kHz, 10min, 146kJ/kg) and no water addition provided an increase in oil extractability of up to 3.8% with respect to the non-sonicated control. A double sonication intervention, before and after malaxation, using low (40kHz) and high (585kHz) frequency, respectively, provided up to 2.4% increase in oil extractability. A megasonic intervention post-malaxation (400 and 600kHz, 57–67min, 18–21kJ/kg) on a pilot scale using early-harvest olive fruits resulted in up to 1.7% extra oil extractability. Oil extracted under a high sonication frequency (free radical production regime) did not impact on olive oil quality parameters at reactor characterisation levels. Megasonic standing wave forces can enhance olive oil separation at various stages of the olive oil extraction process.

Using Nonconventional Water in Irrigation of Olive Trees and Its Effect on Olive Oil Properties

The response of olive orchard with same age and type to irrigation with treated municipal wastewater and freshwater was investigated in three years. Physical and chemical properties of the treated municipal wastewater reuse in agriculture (the effluent) produced by the Sheikh Ejleen wastewater treatment plant in Gaza Strip, freshwater, soil, and olive oil were determined and compared with Palestinian and international standards. The biological oxygen demand (BOD) of Sheikh Ejleen effluent is 60 mg·l-1, which indicates low quality effluent. The results indicate that most of olive oil quality parameters—including heavy metals and trace elements for both fruits irrigated with treated wastewater or irrigated with freshwater—fall within the acceptable standard limit values. Moreover, soil analysis shows that organic content and cation exchange capacity were improved in soil irrigated with treated wastewater in comparison with that irrigated with freshwater. The results also show that there is no trace elements or heavy metals accumulation in soil.

Effect of Ozonated Water Treatment on Fatty Acid Composition and Some Quality Parameters of Olive Oil

ABSTRACTThe organic olives from Çine-Aydın (Turkey) were washed with tap or ozonated water for 2 and 5 min, respectively, and pressed to olive oil. The effects of wash treatments on fatty acid composition and several quality parameters of the oils were determined. The maximum values after 2-min ozonated water washes were 9.58 meqO2/kg, 0.73%, 2.44 and 0.16 for peroxide, free acid, K232 and K270 values, respectively, which were under the standard limits for extra-virgin olive oil. Five min of ozonated water washes also yielded acceptable results, except for a slight excess on K232 value. Ozonated water washes had almost no effect on fatty acid composition.

Monitoring olive oils quality and oxidative resistance during storage using an electronic tongue

Monitoring olive oils oxidative stability and quality parameters (free acidity, peroxide values, K232 and K270 extinction coefficients) is needed to guarantee that, during storage, their levels remain within the legal thresholds enabling their commercialization as high-value extra-virgin olive oils. Physicochemical levels are assessed using time-consuming routine analytical reference techniques. In this work, the feasibility of a novel approach that merges an electronic tongue and chemometric tools, for monitoring extra-virgin olive oils’ quality along one year of storage at dark or exposed to light is discussed. The results confirmed that physicochemical parameters varied with the storage lighting conditions and more significantly with time. Also, multiple linear regression models, using sub-sets of 22–28 sensors selected with a meta-heuristic simulated annealing algorithm, allow evaluating the storage time-evolution of olive oils’ peroxide values, extinction coefficients and oxidative stabilities with satisfactory accuracy (R2 ≥ 0.98 and ≥ 0.96, for leave-one-out and repeated K-fold cross-validation procedures, respectively). The capability of monitoring, in a single electrochemical assay, legal required quality parameters of olive oils, decreases considerable the analysis time and cost, allowing checking the compliance of extra-virgin olive oil quality with labeling. So, the use of electronic tongues for extra-virgin olive oil shelf-life assessment could be envisaged.

Optimization of malaxation process of virgin olive oil using desired and undesired volatile contents

Volatile aroma composition is one of the most important quality parameters of olive oils and changes depend on the maturity and processing methods. In this study, optimization of the malaxation process by response surface methodology (RSM) was aimed in terms of desired and undesired aroma content of oils from olives at three maturity stages. Aroma profile was determined by the head space–solid phase micro-extraction (HS-SPME) method and gas chromatography-mass spectrometry (GC-MS).A full second-order regression model was proposed for the prediction of optimized process responses. The models for desired and undesired volatiles of olive oils extracted from purple and black, except spotted, olive were found to be sufficient for the successful prediction of experimental results. The optimum conditions of temperature and time pairs to maximize desired aroma content and to minimize undesired ones in oil extracted from purple and black olive fruits were found to be 28 °C/38 min, and 29 °C/40 min, respectively.

Quality parameters of olive oil from stoned and nonstoned Koroneiki and Megaritiki Greek olive varieties at different maturity levels

Virgin olive oil is a natural functional food and its beneficial role in health as an integral ingredient of the Mediterranean diet is universally recognized. The effects of olive pitting, degree of ripeness and variety (Greek varieties Koroneiki and Megaritiki) were investigated on the physicochemical characteristics, antioxidant constituent contents and capacity and on the fatty acid profile of olive oil. Ripeness resulted in a decrease ( P P < 0.05) monounsaturated/polyunsaturated fatty acid ratios, which are particularly important for the stability of the oil against oxidation. It was concluded that olive oil from pitted olives maintains a high content in bioactive compounds and a high level of antioxidant activity.

Evaluation of the overall quality of olive oil using fluorescence spectroscopy

The fluorescence spectra of some olive oils were examined in their natural and oxidised state, with wavelength range emissions of 300–800nm and 300–400nm used as excitation radiation. The fluorescence emissions were measured and an assessment was made of the relationship between them and the main quality parameters of olive oils, such as peroxide value, K232, K270 and acidity. These quality parameters (peroxide value, K232, K270 and acidity) are determined by laboratory methods, which though not too sophisticated, they are required solvents and materials as well as time consuming and sample preparation; there is a need for rapid analytical techniques and a low-cost technology for olive oil quality control. The oxidised oils studied had a strong fluorescence band at 430–450nm. Extra virgin olive oil gave a different but interesting fluorescence spectrum, composed of three bands: one low intensity doublet at 440 and 455nm; one strong band at 525nm; and one of medium intensity at 681nm. The band at 681nm was identified as the chlorophyll band. The band at 525nm was derived, at least partially, from vitamin E.The results presented demonstrate the ability of the fluorescence technique, combined with multivariate analysis, to characterise olive oils on the basis of all the quality parameters studied. Prediction models were obtained using various methods, such as partial least squares (PLS), N-way PLS (N-PLS) and external validation, in order to obtain an overall evaluation of oil quality.The best results were obtained for predicting K270 with a root mean square (RMS) prediction error of 0.08 and a correlation coefficient obtained with the external validation of 0.924. Fluorescence spectroscopy facilitates the detection of virgin olive oils obtained from defective or poorly maintained fruits (high acidity), fruits that are highly degraded in the early stages (with a high peroxide value) and oils in advanced stages of oxidation, with secondary oxidation compounds (high K232 and K270). The results indicate the potential of a spectrofluorimetric method combined with multivariate analysis to differentiate, and even quantify, the levels of oil quality. The proposed methodology could be used to accelerate analysis, is inexpensive and allows a comprehensive assessment to be made of olive oil quality.

Optimizing olive harvest time under hot climatic conditions of Jordan Valley, Israel

Global climate change leads to the exposure of olive orchards to higher temperatures than in the past. We followed yield and quality parameters of olive oils from Barnea, Coratina, and Picual, under hot climatic conditions through different levels of ripeness. Oil yield per tree increased throughout the monitoring period due to continuous oil accumulation. Toward the last harvest date, significant fruit drop occurred, which resulted in substantial loss in oil yield. Maximal oil yield was obtained in Barnea at a maturity index of 2.1–2.5, in Coratina at 2.3 and in Picual at 3.2. A reduction in quality parameters was found with delay of harvest date: free fatty acid content increased and the ratio of monounsaturated to polyunsaturated fatty acid declined, but only in one season. Nevertheless, all parameters remained within the trade standard for extra virgin olive oil (EVOO). In contrast to most previous studies, no consistent reduction was observed in total polar phenol content in the oils. Hence, maximizing oil yield should be the main criterion for the determination of harvest date under these conditions. It is therefore suggested that olives exposed to hot climate be harvested earlier than those in typical Mediterranean climate areas.Practical applications: Harvest timing has a strong effect on both oil yield and quality. However, in most of the studies published on the topic until now only a sample of fruit was taken to determine oil accumulation and quality, but little or no information is available on oil yield at tree level, which is an important parameter from the grower's perspective. Moreover, this study describes changes in oil yield and quality along the ripening period, under hot climatic conditions prevailing in Jordan Valley. The Mediterranean basin region, where more than 90% of the world's olive oil is produced is expected to be exposed to higher temperatures in the future due to global climate changes. The current work provides information on the effect of those unfavorable growing conditions on oil production and quality. One of the major findings is the necessity to harvest early (in a relatively low ripening index) under those conditions.

EFFECT OF DIFFERENT IRRIGATION REGIMES ON OLIVE TREE (OLEA EUROPAEA L., 'KORONEIKI') PHYSIOLOGY, YIELD AND FRUIT QUALITY

The effect of different irrigation regimes on physiological parameters (photosynthesis, leaf water potential, stomatal conductance), yield, and fruit quality, was studied in an experimental orchard planted with 50-year-old trees of cultivar 'Koroneiki' in Chania, Crete, Greece. Four treatments were applied as follows: a) fully irrigated trees (FI); b) trees irrigated at 70% ETc (crop evapotranspiration) (DI70); c) trees irrigated at 40% Etc (DI40); and d) rainfed (RF). Irrigation was applied through a drip system, and the seasonal amounts totaled 272, 189 and 108 mm of irrigation water for treatments FI, DI70 and DI40 respectively (May through September), during a year with a typical dry spell of more than 100 days. Leaf water potential was measured between 9:00 and 10:30 AM and ranged from -2.4 to -2.7 MPa for treatments FI and DI70, and from -3.2 to -3.6 for DI40, while in the RF treatment a gradual reduction from -2.5 to -6.3 MPa was observed from the beginning to the end of the dry period. During the dry season, photosynthesis was reduced to 31% and 72% in treatments DI40 and RF respectively, as compared to treatments DI70 and FI. Similarly, fruit yield was reduced by 16.6% and 32% for treatments DI40 and RF, while there was no differentiation between the DI70 and FI treatments. Oil content percentage was increased during maturation in all treatments, with lower values appearing in non-irrigated trees. Olive oil quality parameters (acidity, peroxide value, resistance to oxidation) were not affected significantly by the treatments, with the exception of total phenols, which were lower in oil produced by FI trees. In conclusion, the physiological parameters and the fruit yield were not affected by the application of a deficit irrigation regime of DI70 as compared to FI trees, while both treatments were clearly rated better, compared to the low irrigation regimes (RF and DI40).

A LONG-TERM EXPERIMENT ON OLIVE TREE WITH NITROGEN, PHOSPHORUS AND LIMESTONE FERTILIZATION

In Portugal, a great number of olive groves are located on acid soils, with low levels of organic matter and nutrients, in particular phosphorus. In a mature olive grove, cultivar 'Verdeal Transmontana', located in Mirandela, in the Portuguese region of Tras-os-Montes, a field experiment was established in order to evaluate the effect of N, P and limestone applications on the yield and some quality parameters of olive oil. The experiment, installed on a Cambisol, was arranged into a randomized complete blocks design with three replications and eight experimental treatments resulting from a factorial design with 2 3 combinations of two levels of each factor. The limestone was applied only in the first experimental year (10,000 kg ha -1 ) and P was applied annually, from 1987 to 1994 (0 and 34 kg ha -1 P). Nitrogen was applied annually at 94 and 188 kg ha -1 N from 1987 to 1994, changing to 0 and 78 kg ha -1 N from 1995 to 2006. In this last period, only the residual effect of limestone and P was evaluated. Experimental results obtained from 1995 to 2006 show an increase on fruit-yield due to N and limestone applications, respectively 35% and 18% as compared with the control. Fruit-mean weight and fruit-fat content, as well as the quality parameters of olive oil (acidity, peroxide value, specific absorbance coefficients K 232 and K 270 , total polyphenols, waxes and total sterols), were not significantly affected (p>0.05) by fertilization. In contrast, oxidative stability of olive oil increased with P application. In acid soils with low levels of organic matter it is advantageous to apply limestone and N as it results in higher fruit-yield, without affecting olive oil quality.

INFLUENCE OF NITROGEN AND MAGNESIUM FERTILIZATION OF OLIVE TREE 'PICUAL' ON YIELD AND OLIVE OIL QUALITY

Ribatejo is a Portuguese region with a long tradition in the production of olive oil, being 'Picual' one of the major Spanish cultivar used in intensive olive groves. In this region, a field experiment was established in order to study the influence of nitrogen and magnesium fertilization on fruit yields, fruit characteristics and some quality parameters of olive oil. The olive grove was planted in 1987 on calcareous soils and was managed under dry conditions. Three levels of nitrogen (0, 60 and 120 kg ha -1 N) and magnesium (0, 18 and 36 kg ha -1 Mg) were used, arranged into a factorial experiment with three completely randomized blocks. Nitrogen and magnesium were applied to the soil annually since 1995, as ammonium sulphate and magnesium sulphate, respectively. Experimental results, obtained from 1995 to 2004, show that the fertilization influenced the fruit-yield, fruit-water content and fruit-fat content, with a significantly mean effect (p≤0.05) of the interaction N x Mg regarding the two first parameters. The higher fruit yield was obtained with 60 kg ha -1 N and 36 kg ha -1 Mg, whilst the fruit-fat content decreased with nitrogen application. The maturity index, the fruit-mean weight, the pulp/stone ratio and the evaluated quality parameters of olive oil (acidity, peroxide value, specific absorbance coefficients K 232 and K 270 and oxidative stability) were not significantly affected (p>0.05) by the fertilization.

Improvement of phenolic antioxidants and quality characteristics of virgin olive oil with the addition of enzymes and nitrogen during olive paste processing

The evolution of phenolic compounds and their contribution to the quality characteristics in virgin olive oil during fruit processing was studied with the addition of a combination of various commercial enzymes containing pectinases, polygalacturonases, cellulase and β-glucanase with or without nitrogen flush. Olive fruits ( Olea europaea , L.) of the cultivar Megaritiki, at the semi black pigmentation stage of maturity, were used in a 3-phase extraction system in an experiment at industrial scale. The addition of enzymes in the olive paste during processing increased the total phenol and ortho-diphenol contents, as well as some simple phenolic compounds (3,4-DHPEA, p-HPEA) and the secoiridoid derivatives (3,4-DHPEA-EDA and 3,4-DHPEAEA) in olive oil and therefore improved its oxidative stability. Furthermore, enzyme treatment ameliorated the quality parameters of the produced olive oil (acidity and peroxide value) and their sensory attributes. The use of additional N2 flush with the enzyme treatments did not improve the quality parameters of olive oil any further; however it did not affect the concentration of individual and total sterols or most of the fatty acid composition. Consequently, olive paste treatment with enzymes not only improved the quality characteristics of olive oil and enhanced the overall ogranoleptic quality, but also increased the olive oil yield.

NIR prediction of fruit moisture, free acidity and oil content in intact olives

In this work, the prediction of olive fruit and virgin olive oil quality parameters through the direct measuring of the fruit using near infrared spectrometry (NIRS) has been investigated and the effectiveness of a portable spectrometer has been assessed. Models and calibration tests were developed using both the hexane-isopropanol extraction of individual olive fruits, and the Soxhlet extraction of olive paste. The parameters analyzed were the free acidity in olive oil, oil yield from physical extraction, oil content referring to fresh weight, oil content referring to dry matter and fruit moisture. The results indicate a good predictive potential with both methodologies and serve to encourage improvement in the obtained models through the enlargement of the calibrations. Fruit moisture prediction models showed high accuracy.

The effects of a seaweed extract in addition to nitrogen and boron fertilization on productivity, fruit maturation, leaf nutritional status and oil quality of the olive (Olea europaea L.) cultivar Koroneiki

AbstractBACKGROUND: There is not adequate literature on effects of seaweed extracts (SWE) on yield and nutritional status of olive trees as well as olive oil quality. In this work, a study of the effects of a seaweed extract applied foliarly (0.5% v/v) in addition to soil application of N (500 g NH4NO3 per tree) and B (150 g borax per tree) on productivity, fruit parameters, nutritional status and olive oil quality of a Greek olive cultivar was performed.RESULTS: In contrast to the trees treated with N (NH4NO3) or N + B (NH4NO3 + borax), the additional application of seaweed extract (treatments N + SWE and N + B orax + SWE) increased the productivity and oil content and accelerated maturation of the olive fruits. In particular, the best results concerning productivity, oil content and earliness of maturity (colour and firmness) were observed in the trees treated with N + B + SWE. The additional application of SWE also increased K, Fe and Cu concentrations and reduced the concentrations of Mn in olive leaves compared to the corresponding treatments without SWE. Total phenol concentration in oil was minimized in all fertilization treatments but, particularly, the additional application of SWE did not affect it. The application of N + B + SWE led to a significant increase in linolenic as well as oleic acid concentrations, and to a decline in palmitoleic, stearic and linoleic acid concentrations in olive oil.CONCLUSION: The fertilizer treatments of this experiment and especially the combination of NH4NO3 + borax + SWE should be recommended for the studied olive orchards, in order to increase tree productivity and improve their nutrition status and various olive oil quality parameters. Copyright © 2009 Society of Chemical Industry

Comparison of Fourier Transform near Infrared Spectroscopy Partial Least Square Regression Models for South African Extra Virgin Olive Oil Using Spectra Collected on Two Spectrophotometers at Different Resolutions and Path Lengths

Near infrared (NIR) partial least square (PLS) regression models for the determination of several extra virgin olive oil quality parameters (peroxide value, free fatty acid content, specific extinction coefficients K232 and K270, linoleic, oleic and saturated acid content, α:β ratios of linoleic and oleic acid, pigment and total polyphenol content, thiobarbituric acid reactive substances value) were developed from spectra collected on two different Fourier transform near infrared (FT-NIR) spectrophotometers using different sample holders, path lengths and resolutions. Spectra were recorded on the PerkinElmer IdentiCheck spectrophotometer (9091–4000 cm−1) in transmittance mode at resolutions of 64, 32, 16 and 8 cm−1 at each of two path lengths (0.2 and 0.5 mm) and on the Büchi NIRLab N-200 instrument (10 224–4000 cm−1) in transflectance mode at a fixed resolution of 8 cm−1 and a path length of 0.6 mm. The PLS regression models, for each respective parameter, were statistically compared to evaluate the effect of different sample scanning conditions on model performance. The comparison of the regression models developed from PerkinElmer spectra revealed that spectra recorded at the lowest resolution of 64 cm−1 produced equally accurate models when compared to higher resolution spectra and that the two path lengths resulted in no significant differences. Comparisons between PLS models developed from Büchi and PerkinElmer spectra, respectively, showed significant differences for only a few parameters. In general, reliable prediction results were obtained for the peroxide value [standard error of prediction ( SEP) = 4.15 meq O2 kg−1, r2 = 0.87], K232 ( SEP = 0.94, r2 = 0.94), linoleic acid ( SEP = 0.83%, r2 = 0.90) and saturated acid content ( SEP = 0.91%, r2 = 0.88) PLS regression models.

Excitation−Emission Fluorescence Spectroscopy Combined with Three-Way Methods of Analysis as a Complementary Technique for Olive Oil Characterization

This paper shows the potential of excitation-emission fluorescence spectroscopy (EEFS) and three-way methods of analysis [parallel factor analysis (PARAFAC) and multiway partial least-squares (N-PLS) regression] as a complementary technique for olive oil characterization. The fluorescence excitation-emission matrices of a set of Spanish extra virgin, virgin, pure, and olive pomace oils were measured, and the relationship between them and some of the quality parameters of olive oils (peroxide value, K232, and K270) was studied. N-PLS was found to be more suitable than PARAFAC combined with multiple linear regression for correlating fluorescence and quality parameters, yielding better fits and lower prediction errors. The best results were obtained for predicting K270. EEFS allowed detection of extra virgin olive oils highly degraded at early stages (with high peroxide value) and little oxidized pure olive oils (with low K270). The proposed methodology may be used as an aid to analyze doubtful samples.

Electrochemical sensor and biosensor for polyphenols detection in olive oils

Abstract The aim of the work was to compare different techniques, in evaluating the phenolic content of an extra-virgin olive oil with varying storage time and storage conditions. A disposable screen-printed sensor (SPE) was coupled with differential pulse voltammetry (DPV) to determine the phenolic fractions after extraction with a glycine buffer; DPV parameters were chosen in order to study the oxidation peak of oleuropein, which was used as reference compound. A calibration curve of oleuropein was performed in glycine buffer 10 mM, pH=2, NaCl 10 mM (D.L.=0.25 ppm oleuropein, RSD=7%). Moreover a tyrosinase based biosensor operating in organic solvent (hexane) was also assembled, using an amperometric oxygen probe as transducer. The calibration curves were realised using flow injection analysis (FIA) with phenol as the substrate (D.L.=4.0 ppm phenol, RSD=2%). Both of these methods are easy to operate, require no extraction (biosensor) or rapid extraction procedure (SPE), and the analysis time is short (min). The results obtained with these two innovative procedures were compared with a classical spectrophotometric assay using Folin–Ciocalteau reagent and HPLC analysis. Other extra-virgin olive oil quality parameters were investigated using classical methods in order to better define the alteration process and results are reported.