Olive Oil Extraction Process Research Articles

Modelling Energy Consumption and Energy-Saving in High-Quality Olive Oil Decanter Centrifuge: Numerical Study and Experimental Validation

In this study, an energy consumption model of a decanter centrifuge was proposed, in particular for a technologically evolved machine equipped with an electromechanical recovery system. This model should be suitably coupled with an auto-adaptive controlling technique used to accurately manage the olive oil process. To achieve this goal, a solid physical and theoretical basis that simple to implement is required. To date there have only been limited scientific studies modelling energy consumption applied to the machines used in olive oil extraction processes. Therefore, the model was developed using fluid dynamic analysis and physical constraints to give it a solid basis. It was then simplified sufficiently for future implementation in automatic machine systems. The empirical model was validated through power measurements conducted in two harvesting seasons under varying operating conditions. The model estimates the power absorbed by the bowl and that produced and recovered by the screw, with high accuracy in each harvesting season. When considering the two harvesting seasons as a single season, the prediction accuracy remains considerable, despite a marginal increase in errors (correlation coefficient greater than 0.90). Finally, the model indicates that the screw conveyor speed is the most important parameter to achieve the desired energy recovery level, while the differential speed, which is a process parameter, has only a negligible impact on energy saving.

Implementation of the Sono-Heat-Exchanger in the Extra Virgin Olive Oil Extraction Process: End-User Validation and Analytical Evaluation.

The use of innovative systems, such as the heat exchanger, for production of extra virgin olive oil should allow maintenance of the same quality of those oils derived from traditional processes, and presents specific advantages. The performance of this system was evaluated by (i) determining the parameters directly measurable by the olive millers (i.e., end-user validation based on the production yields when the plant is located in different processing lines) and (ii) assessing the product quality through estimation of the content of phenolic and volatile compounds. The phenols were determined by High Performance Liquid Chromatography with Diode Array Detector (HPLC–DAD) before and after acidic hydrolysis while the volatile fraction was studied by Head-Space Solid-Phase-Micro-Extraction Gas-Chromatography with Mass Detector (HS–SPME–GC–MS). The use of the sono-heat-exchanger presents several advantages: it is a flexible machine, able to interface with all devices of the world’s leading manufacturers of the Extra Virgin Olive Oil (EVOO) extraction plant, and it guarantees shorter processing times and energy savings. Our results also pointed out its capability to increase the oil yields up to 5.5%, particularly when it extracts oil from unripe fruits, which in traditional processes yield oils with higher phenolic contents, but with lower oil yields. Overall, the quality of virgin olive oils was maintained, avoiding decreases of phenolic content or detrimental effects on the sensory characteristics.

Use of Ultrasound and Pef Technologies Applied to the Olive Oil Extraction Process

In this work, ultrasound (US) and pulsed electric fields (PEF) were tested in an industrial olive oil mill. Olives of the cultivar Coratina were processed in a comparative mode, between a traditional process and an innovative process (involving US and PEF). The use of US in addition to the traditional malaxation process led to a significant improvement in extraction yield. PEF also showed a positive effect on extraction yield.The experiments showed the ability of US and PEF to modify the medium, with a consequent increase in the release of oil from cellular vacuoles. The results suggest that research should continue in this direction, by planning other several tests to optimise the machines’ functionality to improve the whole olive oil extraction process.

Toxicity evaluation of olive oil mill wastewater and its polar fraction using multiple whole-organism bioassays

Olive mill wastewater (OMW) as a by-product of olive oil extraction process has significant polluting properties mainly related to high organic load, increased COD/BOD ratio, high phenolic content and relatively acidic pH. Raw OMW from Slovenian Istria olive oil mill and its polar fraction were investigated in this study. Chemical characterization of OMW polar fraction identified tyrosol as the most abundant phenolic product, followed by catechol. Lethal and sub-lethal effects of OMW matrix and its polar fraction were tested using a battery of bioassays with model organisms: bacteria Vibrio fischeri, algae Chlorella vulgaris, water fleas Daphnia magna, zebrafish Danio rerio embryos, clover Trifolium repens and wheat Triticum aestivum. Raw OMW sample was the most toxic to V. fischeri (EC50 = 0.24% of OMW sample final concentration), followed by D. magna (EC50 = 1.43%), C. vulgaris (EC50 = 5.20%), D. rerio (EC50 = 7.05%), seeds T. repens (EC50 = 8.68%) and T. aestivum (EC50 = 11.58%). Similar toxicity trend was observed during exposure to OMW polar fraction, showing EC50 values 2.75–4.11 times lower comparing to raw OMW. Tested samples induced also sub-acute effects to clover and wheat (decreased roots, sprouts elongation); and to zebrafish embryos (increased mortality, higher abnormality rate, decreased hatching and pigmentation formation rate). A comprehensive approach using a battery of bioassays, like those used in this study should be applied during ecotoxicity monitoring of untreated and treated OMW.

Comparative analyses of three olive mill solid residues from different countries and processes for energy recovery by gasification

Biomass is a renewable energy source which may provide a significant contribution to the reduction of fossil fuels consumption and the associated environmental impacts. The use of agricultural or agro-industrial waste such as solid residues from olive oil production is particularly relevant since it may combine several benefits. Gasification is a promising waste-to-energy technique for this type of lignocellulosic residues. The technology however is adapted to a relatively limited panel of solid waste fuels of defined specifications, which must therefore be characterized properly to assess their adaptation. The purpose of this research was to analyze and compare three different olive mill solid residues by complementary techniques such as Fourier transform infrared spectroscopy (FTIR) and thermochemical methods, in order to characterize these residues as potential fuels for gasification. The results obtained underlined the complex nature of the residues and indicated that they were mainly organic, with very little mineral matter. In addition to the major organic components (cellulose, hemicelluloses and lignin), the presence of several minor organic constituents was shown by thermogravimetry coupled to differential scanning calorimetry and FTIR. The gas produced from pyrolysis was analyzed by gas chromatography and mass spectrometry. It was found to contain several degradation products from lignocellulosic material and olive oil, such as hydroxyacetone, furfural and methoxyphenols. The influence of the olive oil extraction process (two-phase or three-phase) was also demonstrated. It was shown that the thermochemical degradation of olive mill residues followed a complex pathway but the composition of the residues met the requirements for gasification for most parameters.

Industrial Ultrasound Applications in The Extra-Virgin Olive Oil Extraction Process: History, Approaches, and Key Questions.

Taking an idea from a basic concept to a commercially available product is highly rewarding, but it can be a very long, complex, and difficult journey. Recognizing and understanding the stages of the process and using the right support to help you navigate through it can mean all the difference between success and failure. The road from concept to market is marred with obstacles, and many businesses fail to pass beyond the development stage. A better understanding of the innovation process is essential from the outset if the pioneers of innovation are to overcome the dangers that they are likely to face along the way and maximize their opportunities for success. In the olive oil sector, the most recent radical innovation is the introduction of ultrasound into the industrial extraction process. Many efforts have been made in order to overcome the Valley of Death. The strategy of designing, implementing, and testing an innovative system that combines the mechanical energy of ultrasound with the possibility of modulating the thermal exchange of olive paste (heating or cooling) has enabled the following: (1) Eliminating malaxation by realizing a real continuous process; (2) raising extraction yields by recovering a further quota of extra-virgin olive oil that is usually lost in the pomace; (3) improving the content of antioxidant molecules simultaneously with yields; and (4) offering a sustainable plant solution that can guarantee the right income for producers.

Chemical composition and in vitro digestibility of alternative feed resources for ruminants in Mediterranean climates: olive cake and cactus cladodes

AbstractOlive cake (OC) and cactus cladodes (CCs) are two alternative feed resources widely available in Mediterranean areas. Their use in ruminant diets was assessed according to their chemical composition, secondary compound levels and digestibility. The effects of the olive oil extraction period and process, and CCs age and sampling period were evaluated. OC was collected monthly, from November to January, from mills using either a mechanical press or 2-phase or 3-phase centrifugation processes. CCs were collected fortnightly according to age (young and mature) from April to June. Two-phase OC had the lowest content of dry matter (DM), the highest nitrogen-free extract (NFE) and total and hydrolysable tannins and was more rapidly fermentable. Mechanical press OC was the least digestible. OC DM, protein and NFE were affected linearly by the extraction period. Gas production (GP),in vitrodigestibility parameters and dry and organic enzymatic digestibility changed with the extraction period. Therefore, OC chemical composition andin vitrodigestibility depended mainly on the extraction process and period. Compared to mature CCs , young CCs contained more water, protein, ether-extract and phenolic compounds, but less ash and fibre. GP and digestibility parameters were not affected by age, butin vitroorganic matter digestibility and microbial biomass production were higher in young cladodes. CCs chemical composition, GP and digestibility parameters were influenced by the collection period. Due to its limited nutritional quality, OC should be enriched in nitrogen, while CCs could be considered as highly valuable forage in ruminant diet.

Chemical Coagulation/Flocculation Processes for Removal of Phenolic Compounds from Olive Mill Wastewater: A Comprehensive Review

Olive oil extraction processes generate three phases: Olive oil, solid residue (pomace) and aqueous liquor Olive Mill Wastewater (OMW). OMW causes serious environmental deteriorations such as coloring of natural waters, alteration of soil quality, phytotoxicity and odor nuisance. The direct discharge of this effluent into the soil bring various negative effects on the environment, due to its high load of organic matter and phenolic compounds. Coagulation, flocculation and their combination processes are among the most applied processes for wastewater treatment. The application of coagulation technique using mineral and inorganic polymeric coagulants and acid cracking is not always effective to reduce COD and phenolic compounds from OMW except lime. Although direct flocculation is a low treatment cost, use less chemical and produce less sludge, the efficiency of COD and phenolic compounds removal remain very low. Coagulation-flocculation process is developed in order to enhance the removal efficiency of organic matter from OMW by optimizing the operating conditions. However, many studies showed that the combination of various cationic organic coagulant and flocculant agents did not show any significant decrease of COD and phenolic compounds except for lime combination. In the present review, recent research studies dealing with the application of coagulation/flocculation for removal of phenolic compounds and COD from OMW are presented and compared. Furthermore, the main factors that influence the selection between coagulation, direct flocculation and coagulation-flocculation are presented and the principal removal mechanisms are discussed.

Treatment of Two-Phase Olive Mill Wastewater and Recovery of Phenolic Compounds Using Membrane Technology.

The semi-solid wastes (pomace or alperujo) produced in the two-phase olive oil extraction process contains extremely high organic load and phenolic substances. Efficient treatment of such kinds of wastes using membrane filtration, should be sought to reduce the hazardous effects to the environment. On the other hand, phenolic compounds can be isolated and purified up to a level of commercial exploitation using the membrane technology. Firstly, the extraction process with mixtures of water and ethanol was optimized by testing extraction parameters (e.g., solvent’s mixture, duration, and temperature) at laboratory scale. Next, extraction was conducted using larger volumes and the treatment was continued in a pilot membrane filtration system, consisted of ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes. The extracted solution from the olive oil pomace was fed to the pilot membrane filtration system, where all fat, lipids, and solids were removed while the phenolic compounds were concentrated in the retentate streams of NF and/or RO. Total phenolic content (TPC) at the RO’s concentrate stream was 225 mg/L and at the final effluent was lower than 10 mg/lt. The chemical oxygen demand (COD) value at the final effluent was much lower (~280 mg/L) than in the feed stream (>32,000 mg/L).

Supercritical fluid extraction for enhancing polyphenolic compounds production from olive waste extracts

AbstractBACKGROUNDA number of residues are produced during the olive oil extraction process, such as crushed pits, olive leaves, pomace and exhaust olive pomace. In addition, pruning of olive trees results in a huge amount of biomass. All of these lignocellulosic materials constitute a source of energy and chemicals that can be used as raw materials in biorefineries. Among them, antioxidants are of particular interest due to their potential applications in pharmaceutical and food industry.RESULTSSupercritical fluid extraction (SFE) was applied on three different olive residues – pruning biomass, leaves and exhaust pomace. In this, 60% ethanol was used as cosolvent at three different pressure levels, 200, 250 and 300 bar. The best conditions for each residue were determined and compared with conventional extraction. Results show that 300 bar was the best pressure for SFE in terms of antioxidant activity of the extracts. The main polyphenolic compounds also were identified, among which hydroxytyrosol, chlorogenic acid, caffeic acid and ferulic acid were present.CONCLUSIONSFE at 300 bar proved to be the best option for obtaining a high‐activity antioxidant extract from olive leaves, exhaust pomace and pruning biomass, with hydroxytyrosol the prominent compound detected. This procedure could be integrated in a biorefinery based on olive‐derived biomass. © 2018 Society of Chemical Industry

A Qualitative Analysis of Innovation Adoption in the Olive Oil Extraction Process

Pressures on the Italian olive oil sector have increased over the past few years due to seasons of bad weather, small innovation capacity and limited long-term investment plans. Thus, it is of interest to explore signs of positive attitude towards innovation investment in the agricultural sector. The focus has been on technologies employed in the extraction process, since yield and quality of olive oil are mostly affected by this stage. To define the determinants of innovation adoption, 13 managers were interviewed. Questions covered organisation factors, personal factors, social factors, the impact of the olive oil value chain and the cost of the extraction machinery. The results of the thematic analysis showed that determinants of innovation adoption were: perceived usefulness, personal innovativeness, prior experience, influence of peers, training and managerial support, and the relative importance of quality, while major challenges are the lack of financial funds, demand pressure from customers, and lack of early warning systems to tackle bad weather conditions.

Physico-chemical characterization of olive-oil mill wastewaters of Ben Karrich area (Tetouan province, North of Morocco) and optimization study of their treatment using activated carbon

A physio-chemical characterization of olive oil mill wastewater (OMW) obtained from a continuous two-phases olive oil extraction process is presented. High organic load of OMW from Ben Karrich region has been registered. The values of chemical oxygen demand (COD) and total phenolic compounds were 84.5 g of O2/L and 3.79 g/L, respectively. In this sense, a treatment using activated carbon as adsorbent was proposed. Results have shown high removal percentages in total phenolic compounds (98%) and COD (90%). The optimal operating conditions were 4 g of activated carbon and adsorbing time equal to 5 minutes.

Combined industrial olive oil extraction plant using ultrasounds, microwave, and heat exchange: Impact on olive oil quality and yield

In this study, an industrial combined plant (ICP) constructed from a low-frequency ultrasound device, microwave apparatus and heat exchanger is employed to investigate the real possibility of introducing these innovative technologies to the olive oil extraction process and evaluating their influence on olive oil quality and yield. The novelty of this study lies in the simultaneous use of these three technologies to condition the olive paste in a real olive oil extraction plant.Different olive paste treatments were compared in order to define the effects on the olive oil quality and yield.The use of a spiral heat exchanger in addition to the malaxer reduced the malaxation time to 20 min, and with the microwave apparatus it was possible to obtain an entirely continuous process, without interruptions, from the milling phase to the solid-liquid separation phase.The internal spiral aids in moving the paste from the input to output section, resulting in limited operating pressure.Using the ICP device led to an average increase in extractability ranging from 2.30 to 3.85% with respect to the control thesis, for the Arbosana and Arbequina varieties, respectively, but this difference was not statistically significant.Regarding the virgin olive oil (VOO) quality, the use of the ICP did not affect the marketable parameters and total phenol content, while in terms of the process efficiency, the ICP obtained a higher value than the conventional process and improved the extraction yield.

Olive Mill Wastewater (OMW) Treatment by Using Ferric Oxide Dephenolization and Chemical Oxygen Demand Removal

<p>In Jordan and as in many other Mediterranean countries olive oil production is one of the major agricultural production, it is estimated that the annual production of olive oil in Jordan approximately 21.5 thousand tons per year. O the other hand the process of olive oil extraction generates around 200,000 m3 of olive mill wastewater (OMW) and it is considered as a a serious problem in. In this study the real sample of wastewater is collected from the outlet at the mill near by the university campus. The analysis of this collected wastewater has shown a very high Chemical Oxygen Demand COD (253.648 kg/l) and Bilogical Oxygen Demand, BOD (89.365kg/l). These high BOD and COD reveals a real need to treat it before sent to municipal sewage. The study also focuses on reducing an organ phenol component which has been measured and found equal to 0.5698mg/l. The use of Ferric Oxide in the form of nanoparticles was successfully used to oxide organic phenols from olive mill wastewater (OMW) and has reduced to 0.002 mg/l. The results show that 0.1g of Ferric Oxide in the form of nanoparticles when mixed with sand has the capacity to remove the phenols from the collected samples. The removal percentage obtained here reached 97%. When the mixture of ferric nanoparticles used with sand in a ratio of 0.1 g Fe2O3and 1 kg of sand, the removal capacity of organic phenols has reached to 99%, and COD () in percentage of 97.2%. The results show an interesting behavior towards other minerals that exists in solution, that ferric nanoparticles have a good capacity to remove Cr+3Cu+3 K+Ca+2Na+.minerals exist in wastewater.</p>

WEEE data management in Germany and Serbia

<p>In Jordan and as in many other Mediterranean countries olive oil production is one of the major agricultural production, it is estimated that the annual production of olive oil in Jordan approximately 21.5 thousand tons per year. O the other hand the process of olive oil extraction generates around 200,000 m3 of olive mill wastewater (OMW) and it is considered as a a serious problem in. In this study the real sample of wastewater is collected from the outlet at the mill near by the university campus. The analysis of this collected wastewater has shown a very high Chemical Oxygen Demand COD (253.648 kg/l) and Bilogical Oxygen Demand, BOD (89.365kg/l). These high BOD and COD reveals a real need to treat it before sent to municipal sewage. The study also focuses on reducing an organ phenol component which has been measured and found equal to 0.5698mg/l. The use of Ferric Oxide in the form of nanoparticles was successfully used to oxide organic phenols from olive mill wastewater (OMW) and has reduced to 0.002 mg/l. The results show that 0.1g of Ferric Oxide in the form of nanoparticles when mixed with sand has the capacity to remove the phenols from the collected samples. The removal percentage obtained here reached 97%. When the mixture of ferric nanoparticles used with sand in a ratio of 0.1 g Fe2O3and 1 kg of sand, the removal capacity of organic phenols has reached to 99%, and COD () in percentage of 97.2%. The results show an interesting behavior towards other minerals that exists in solution, that ferric nanoparticles have a good capacity to remove Cr+3Cu+3 K+Ca+2Na+.minerals exist in wastewater.</p>

Use of a mixing-coil heat exchanger combined with microwave and ultrasound technology in an olive oil extraction process

Abstract This study addressed the possibility to improve the conditioning process of olive paste in order to make the extra-virgin olive oil (EVOO) extraction process in a continuous and rapid manner than the traditional one. An innovative heat exchanger, the mixing-coil heat exchanger (MCHE), having a mixing-coil inside was employed. Also, a continuous microwave machine (MW) and ultrasonic machine (US) prototypes were joined to it. These three prototypes were installed in a commercial olive oil extraction plant. Four conditioning processes (ML; MCHE; MCHE + ML, MCHE + MW and MCHE + US + MW) employing the prototypes were compared to the traditional one (ML) in which only one malaxer machine was employed to condition the olive paste. Olive oil extractability index (E) and olive paste rheological parameters were determined. The use of MCHE alone showed the worst results in terms of extractability (E = 74.03), having processing time of 3.84 min. Moreover, the not sufficient paste treatment didn't permit the optimal working of the three-phase decanter. Consequently, the highest solids amount in waste water was registered, compared with the other conditioning processes considered. Using the MW coupled to MCHE permitted the reduction of the conditioning time to 4.19 min instead of 40 min of ML condition, and made the process continuous, cause the employment of MW and MCHE (continuous machines) instead of ML (discontinuous machine). The E registered (85.76) resulted statistically equal to those of the traditional conditioning (E = 85.91) and MCHE − ML (E = 85.78). Conditioning time of the latter was 23.84 min. Using the three prototypes together, the investigators confirmed a process continuity and conditioning time of 5.80 min and found a value of E equal to 87.16%, not statistically different form the E value of ML conditioning process. The specific energies employed were 15.75 and 25.71 kJ kg−1 for MCHE + MW and MCHE + US + MW, respectively. Industrial relevance text The present study addressed the use of an innovative heat exchanger, provided by an inner mixing spring, to fast condition the olive paste. It was used also in combination with an ultrasound machine and a microwave machine. The microwave machine leads to the extraction efficiency increasing and the ultrasound machine improves slightly the extraction efficiency. The results demonstrated these new technologies are able to substitute the classical malaxation operation discontinuous and time costly. Moreover, the layout of the plant resulted simplest and smallest than the traditional one.

Evolution of physical-chemical parameters, microbial diversity and VOC emissions of olive oil mill waste exposed to ambient conditions in open reservoirs

In the olive oil extraction process, 20% olive oil is obtained. About 80% corresponds to waste, mainly alperujo and orujo. When these residues are stored in open reservoirs for later stabilization or potential reuse, odorous Volatile Organic Compounds (VOCs) are generated as products of waste decomposition. In this work, these emissions were studied by means of TD-GC/MS in relation to the changes in the physical-chemical (ashes, moisture, total phenols, pH, proteins, fibers, oils, fats) and biological parameters (bacterial and fungal diversity in Illumina platform) of waste for 6 months. The dynamics of these parameters were statistically related to the evolution of environmental variables (temperature, relative humidity, precipitation) and their effects on the most relevant physical-chemical parameters in order to evaluate their incidence in odorant VOCs emissions over time. The results showed a progressive increase in the diversity of both fungi and bacteria that were related, mainly, to a progressive decrease in the concentration of fatty acid methyl esters and the concentration of alkenes in the emissions; and to an increase of odorous compounds, mainly aldehydes, ketones and carboxylic acids, which were responsible for the unpleasant odors of waste. No significant differences were observed between the evolution of orujo characteristics compared to those of alperujo.

“Biosynthesis of volatile compounds by hydroperoxide lyase enzymatic activity during virgin olive oil extraction process”

The approach of this research was to describe the biochemical transformations of minor components of virgin olive oil with high impact on its sensory quality, specifically “volatile compounds” during its extraction process. For this purpose `Picual´, `Arbequina´ and `Hojiblanca´ cultivars were processed at three different harvesting times. Their volatile profiles and levels of enzymatic activity of “hydroperoxide lyase”, responsible for the biosynthesis of C6 aldehydes related to “green and fruity notes”, were monitored and identified in mesocarp, paste before kneading and paste after kneading based on the catalytic action of crude enzyme extracts. Both of them, volatiles and HPL, were analyzed by incubating with their corresponding substrates and reaction products formed were analyzed by Solid Phase Microextraction-Gas Chromatography and Mass Spectrometry. The results obtained in the present research can be useful in order to develop new markers biochemical whereby improved aroma quality in olive breeding programs or in the design of new protocol of VOO extraction.

Optimization of olive-oil extraction using nonlinear H-infinity control

Abstract Olive-oil extraction is a process carried out by thousands of small industrial units in the Mediterranean countries (olive-oil mills), often in an empirical manner and using heuristic parametrization. The article proposes a new nonlinear H-infinity control approach for optimizing olive-oil extraction. The state-space model of the olive-oil extraction process is formulated after taking into account time-delays between the control inputs and its outputs. This state-space model undergoes approximate linearization around a temporary operating point which is re-computed at each step of the control method. The linearization is based on Taylor series expansion and on the computation of the model’s Jacobian matrices. For the approximately linearized description of the olive-oil extraction system an optimal (H-infinity) feedback controller is designed. The computation of the controller’s feedback gain requires the solution of an algebraic Riccati equation which also takes place at each iteration of the control method. The stability properties of the H-infinity control scheme are proven through Lyapunov analysis.

Some Technological Pretreatments Applied During Olive Oil Extraction: Impacts on Quality Parameters and Minor Constituents

The mechanically extraction of olive oil has three main steps: preparation of the paste (crushing with a mechanical metal crusher and kneading with malaxer), solid-liquid and liquid-liquid separation (horizontal-axis centrifugal separator (decanter)). For every extraction process (solid-liquid separation type), the factors such as temperature, time, adjuvants, amount of processing water oxygen and processing type can be changed. Moreover, the need to production of high-quality virgin olive oil at the highest yield and minimum cost, as well as using an environmentally friendly olive oil production encourages the processing of olive oil in different forms and research of new technologies. The main goal for this purpose is to reduce the process time and increase the extraction yield along with transform the discontinuous malaxing step in a continuous phase and improve the working capacity. Another important aspect to consider is the reduction of energy requirements of the process, thereby reducing both environmental and financial costs. This trend triggered the rapid progress in the application of emerging technologies in olive processing. Ultrasounds (US), microwaves (MW), and pulsed electric fields (PEF), flash thermal conditioning (FTC) are emerging technologies that have already found application in the virgin olive oil extraction process on pilot scale plants. This paper aims to describe the basic principles of these technologies as well as the results concerning their impact on virgin olive oil yields. In this review, different technological processes being implemented in recent years to prevent the loss caused by the conventional methods in the production of olive oil and effects of these technological treatments on quality and chemical characteristics of the olive oil is gathered.