Physicochemical characterization of virgin olive oil obtained using an ultrasound-assisted extraction at an industrial scale: Influence of olive maturity index and malaxation time

Importance of malaxation conditions to virgin olive oil polar phenolic compounds content

Virgin olive oil (VOO), the "golden liquid" of the Mediterranean diet (MD), has experienced rising global consumption due to its health-related properties and remarkable sensory attributes. VOO's health benefits are linked mainly to its fatty acid and phenolic profiles. Polar phenolic compounds (PPCs) contribute to the VOO quality and sensory-nutritional aspects, being responsible for the only health claim regarding its protective influence on the oxidation of blood lipids. VOO's phenols are influenced by the rate of their solubilisation and the chemical/enzymatic reactions during processing, significantly affected by technological factors. Malaxation plays a significant role in VOO's PPCs content. This review highlights recent technological advances in VOO extraction, particularly the impact of malaxation on PPCs. Non-thermal methods, such as pulsed electric field and ultrasound show promise in improving PPCs content, especially secoiridoids. Future research efforts should focus on industrial-level studies and optimising extraction per olive genotype to standardise high-quality VOO production.

Industrial Production of Bioactive Nutrient-Enhanced Extra Virgin Olive Oil under Continuous-Flow Ultrasound and Pulsed Electric Field Treatment

Extra virgin olive oil (EVOO) is a cornerstone of the Mediterranean diet. Many studies have highlighted its crucial preventive role against cardiovascular disease, neurodegenerative disorders, metabolic syndrome and cancer, with these effects being due to the synergistic anti-inflammatory and antioxidant activities of minor components, such as polyphenols and tocols. The aim of the present study is to implement new technologies for olive oil mills and develop an efficient large-sized industrial process for the continuous extraction of healthier EVOOs that are enriched with these bioactive compounds. Non-thermal technologies, namely ultrasound (US) and pulsed electric field (PEF), have been tested, separately and in combination, to eliminate the need for traditional malaxation. There is extensive literature to support the efficacy of ultrasound-assisted extraction (UAE) and PEF treatments in EVOO production. A newly designed US device and a PEF industrial chamber have been combined into a single, integrated continuous-flow setup, the performance of which in the extraction of EVOO from green Coratina olives has been evaluated herein. Extraction yields, physico-chemical and organoleptic characteristics, and polyphenol and tocol contents were monitored throughout the trials, and the last three were measured at accelerated aging times (AAT) of 15 and 30 days. The US and combined US-PEF processes not only increased daily oil production (ton/day, by nearly 45%), but also eliminated the need for kneading during malaxation, resulting in significant energy savings (approximately 35%). In addition, these innovations enriched the resulting EVOO with nutritionally relevant minor components (8-12% polyphenols, 3-5% tocols), thereby elevating its quality and market value, as well as overall stability. The introduction of continuous-flow US and PEF technologies is a remarkable innovation for the EVOO industry, as they offer benefits to both producers and consumers. The EVOO resulting from non-thermal continuous-flow production meets the growing demand for healthier, nutrient-enriched products.

Exploring the relevance of the type of horizontal separator to optimize the extraction efficacy for the Arbequina variety

The productivity of virgin olive oil depends not only on agronomic factors but also on the technological factors of the extraction process. The 'Arbequina' variety has extractability problems, which is a challenge for master millers anywhere. This work aims to evaluate the behavior of different decanters and seeks to modulate the effect of some processing parameters and their interactions with oil extraction efficiency in the case of 'Arbequina.' Fruit characteristics, processing parameters, and extractability were collected over 10 years from 38 decanters that belong to five different brands. The results have shown that fruit moisture is the most relevant factor for oil extractability, especially over 52%. Furthermore, extractability is positively correlated with malaxing temperature, addition of water, and total fat content in the fruit. However, the results show that before applying a regulation, the type of decanter must be considered. The model used in this study has allowed us to optimize the regulations for each type of decanter to reduce oil losses within the pomace, achieving an extraction efficiency within the range of 78%-91.5%. In fact, the best extraction efficiency results (91.5%) were obtained by processing at temperatures >26°C and water injection of 5%.

Neolignans with anti-inflammatory activity from Piper kadsura (Choisy) Ohwi

Two novel neolignans, piperkadsurenin A (1) and kadsurenin N (2), along with six known neolignans (3-8) and two lignans (9-10) were isolated from the stems of Piper kadsura (Choisy) Ohwi. Extensive spectroscopic data interpretation and ECD calculations were used to identify the structures of the new compounds 1 and 2. Especially, compound 1 represents the first example of neolignan with cyclopenta[b]pyran framework. The anti-inflammatory efficacy of compounds 1-10 in vitro was systematically assessed through NO production inhibitory assay. Compounds 3 and 7 significantly inhibited LPS-induced NO generation in RAW 264.7 cells, with IC50 values of 34.29 ± 0.82 and 47.5 ± 5.81 μM, respectively.

A comprehensive review of ultrasonic assisted extraction (UAE) for bioactive components: Principles, advantages, equipment, and combined technologies

The increasing focus on health and well-being has sparked a rising interest in bioactive components in the food, pharmaceutical, and nutraceutical industries. These components are gaining popularity due to their potential benefits for overall health. The growing interest has resulted in a continuous rise in demand for bioactive components, leading to the exploration of both edible and non-edible sources to obtain these valuable substances. Traditional extraction methods like solvent extraction, distillation, and pressing have certain drawbacks, including lower extraction efficiency, reduced yield, and the use of significant amounts of solvents or resources. Furthermore, certain extraction methods necessitate high temperatures, which can adversely affect certain bioactive components. Consequently, researchers are exploring non-thermal technologies to develop environmentally friendly and efficient extraction methods. Ultrasonic-assisted extraction (UAE) is recognized as an environmentally friendly and highly efficient extraction technology. The UAE has the potential to minimize or eliminate the need for organic solvents, thereby reducing its impact on the environment. Additionally, UAE has been found to significantly enhance the production of target bioactive components, making it an attractive method in the industry. The emergence of ultrasonic assisted extraction equipment (UAEE) has presented novel opportunities for research in chemistry, biology, pharmaceuticals, food, and other related fields. However, there is still a need for further investigation into the main components and working modes of UAEE, as current understanding in this area remains limited. Therefore, additional research and exploration are necessary to enhance our knowledge and optimize the application of UAEE. The core aim of this review is to gain a comprehensive understanding of the principles, benefits and impact on bioactive components of UAE, explore the different types of equipment used in this technique, examine the various working modes and control parameters employed in UAE, and provide a detailed overview of the blending of UAE with other emerging extraction technologies. In conclusion, the future development of UAEE is envisioned to focus on achieving increased efficiency, reduced costs, enhanced safety, and improved reliability. These key areas of advancement aim to optimize the performance and practicality of UAEE, making it a more efficient, cost-effective, and reliable extraction technology.

Natural complex substances: From molecules to the molecular complexes. Analytical and technological advances for their definition and differentiation from the corresponding synthetic substances

Natural complex substances (NCSs) are a heterogeneous family of substances that are notably used as ingredients in several products classified as food supplements, medical devices, cosmetics and traditional medicines, according to the correspondent regulatory framework. The compositions of NCSs vary widely and hundreds to thousands of compounds can be present at the same time. A key concept is that NCSs are much more than the simple sum of the compounds that constitute them, in fact some emerging phenomena are the result of the supramolecular interaction of the constituents of the system. Therefore, close attention should be paid to produce and characterize these systems. Today many natural compounds are produced by chemical synthesis and are intentionally added to NCSs, or to formulated natural products, to enhance their properties, lowering their production costs. Market analysis shows a tendency of people to use products made with NCSs and, currently, products made with ingredients of natural origin only are not conveniently distinguishable from those containing compounds of synthetic origin. Furthermore, the uncertainty of the current European regulatory framework does not allow consumers to correctly differentiate and identify products containing only ingredients of natural origin. The high demand for specific and effective NCSs and their high-cost offer on the market, create the conditions to economically motivated sophistications, characterized by the addition of a cheap material to a more expensive one, just to increase profit. This type of practice can concern both the addition of less valuable natural materials and the addition of pure artificial compounds with the same structure as those naturally present. In this scenario, it becomes essential for producers of natural products to have advanced analytical techniques to evaluate the effective naturalness of NCSs. In fact, synthetically obtained compounds are not identical to their naturally occurring counterparts, due to the isotopic composition or chirality, as well as the presence of different trace metabolites (since pure substances in nature do not exist). For this reason, in this review, the main analytical tests that can be performed to differentiate natural compounds from their synthetic counterparts will be highlighted and the main analytical technologies will be described. At the same time, the main fingerprint techniques useful for characterizing the complexity of the NCSs, also allowing their identification and quali-quantitative evaluation, will be described. Furthermore, NCSs can be produced through different manufacturing processes, not all of which are on the same level of quality. In this review the most suitable technologies for green processes that operate according to physical extraction principles will be presented, as according to the authors they are the ones that come closest to creating more life-cycle compatible NCSs and that are well suited to the European green deal, a strategy with the aim of transforming the EU into a sustainable and resource-efficient society by 2050.

Ultrasound Assisted Coextraction of Cornicabra Olives and Thyme to Obtain Flavored Olive Oils

Flavoring olive oils is a new trend in consumer preferences, and different enrichment techniques can be used. Coextraction of olives with a flavoring agent is an option for obtaining a flavored product without the need for further operations. Moreover, ultrasound (US) assisted extraction is an emergent technology able to increase extractability. Combining US and coextraction, it is possible to obtain new products using different types of olives (e.g., cultivar and ripening stage), ingredient(s) with the greatest flavoring and/or bioactive potential, as well as extraction conditions. In the present study, mastic thyme (Thymus mastichina L.) (TM) and lemon thyme (Thymus x citriodorus) (TC) were used for flavoring Cornicabra oils by coextraction. The coextraction trials were performed by (i) thyme addition to the olives during crushing or malaxation and (ii) US application before malaxation. Several parameters were evaluated in the oil: quality criteria parameters, total phenols, fatty acid composition, chlorophyll pigments, phenolic profile and oxidative stability. US application did not change the phenolic profile of Cornicabra olive oils, while the enrichment of olive oils with phenolic compounds or pigments by coextraction was very dependent on the thyme used. TM enrichment showed an improvement of several new phenolic compounds in the oils, while with TC, fewer new phenols were observed. In turn, in the trials with TC, the extraction of chlorophyll pigments was higher, particularly in crushing coprocessing. Moreover, the oils obtained with US and TM added in the mill or in the malaxator showed lower phenol decrease (59%) than oils flavored with TC (76% decrease) or Cornicabra virgin olive oil (80% decrease) over an 8-month storage period. Multivariate data analysis, considering quality parameters, pigments and phenolic contents, showed that flavored oils were mainly grouped by age.

Innovative technologies to enhance oil recovery

The processes for extracting and refining edible oils are well-established in industry at different scales. However, these processing lines encounter inefficiencies and oil losses when recovering crude or refined oil. Palm oil and olive oil extraction methods are used mainly as a combination of physical, thermal, and centrifugal methods to recover crude oil, which results in oil losses in the olive pomace or in palm oil effluents. Seed oils generally require a seed steam conditioning, and cooking stage, followed by physical oil recovery through an inefficient expeller. Most of the crude oil remaining in the expeller cake is then recovered by hexane. Crude seed oil is further refined in stages that also undergo oil losses. This chapter provides an overview of innovative technologies using microwave, ultrasound, megasonic and pulsed electric field energies, which can be used in the above-mentioned crude and refined oil processes to improve oil recovery. This chapter describes traditional palm oil, olive oil, and seed oil processes, as well as the specific process interventions that have been tested with these technologies. The impact of such technology interventions on oil quality is also summarized.

Green extraction of carotenoids from apricot flesh by ultrasound assisted corn oil extraction: Optimization, identification, and application

The valorization of waste apricot flesh (WAF) can solve environmental and economic problems, and also meets the demand for natural pigments. Therefore, the aim of this paper was to recover carotenoids from WAF, to determine the type and content of carotenoids in the extracts and to explore the potential of the extracts for food industry applications. The extraction conditions were optimized. The total carotenoids content (TCC) was 42.75 mg/100 g dried weight under the optimized conditions: Time: 60 min, Temperature: 41.53℃, Power: 200 W, Liquid to solid (LS) ratio: 0.10 g/mL. The highest content of carotenoids in the corn oil extracts (COE) was phytoene. Color of COE under high temperature was investigated. Carotenoids in the COE were degraded at high temperatures. The a* of fries fried by COE was 7.31 times higher than that of corn oil. This study provides guidance for the green recovery of carotenoids and valorization of WAF.

Effect of Controlled Oxygen Supply during Crushing on Volatile and Phenol Compounds and Sensory Characteristics in Coratina and Ogliarola Virgin Olive Oils

In virgin olive oil industries, the technological choices of the production plant affect the biochemical activities that take place in the olives being processed throughout the entire process, thereby affecting the quality of the final product. The lipoxygenase pool enzymes that operated their activity during the first phases of the process need the best conditions to work, especially concerning temperature and oxygen availability. In this study, a system was equipped to supply oxygen in the crusher at a controllable concentration in an industrial olive oil mill at pilot plant scale, and four oxygen concentrations and two cultivars, Coratina and Ogliarola, were tested. The best concentration for oxygen supply was 0.2 L/min at the working capacity of 0.64 Ton/h. Further, using this addition of oxygen, it was possible to increase the compound's concentration, which is responsible for the green, fruity aroma. The effect on volatile compounds was also confirmed by the sensory analyses. However, at the same time, it was possible to maintain the concentration of phenols in a good quality olive oil while also preserving all the antioxidant properties of the product due to the presence of phenols. This study corroborates the importance of controlling oxygen supply in the first step of the process for process management and quality improvement in virgin olive oil production.

Plant Extraction in Water: Towards Highly Efficient Industrial Applications

Since the beginning of this century, the world has experienced a growing need for enabling techniques and more environmentally friendly protocols that can facilitate more rational industrial production. Scientists are faced with the major challenges of global warming and safeguarding water and food quality. Organic solvents are still widely used and seem to be hard to replace, despite their enormous environmental and toxicological impact. The development of water-based strategies for the extraction of primary and secondary metabolites from plants on a laboratory scale is well documented, with several intensified processes being able to maximize the extraction power of water. Technologies, such as ultrasound, hydrodynamic cavitation, microwaves and pressurized reactors that achieve subcritical water conditions can dramatically increase extraction rates and yields. In addition, significant synergistic effects have been observed when using combined techniques. Due to the limited penetration depth of microwaves and ultrasonic waves, scaling up entails changes to reactor design. Nevertheless, the rich academic literature from laboratory-scale investigations may contribute to the engineering work involved in maximizing mass/energy transfer. In this article, we provide an overview of current and innovative techniques for solid-liquid extraction in water for industrial applications, where continuous and semi-continuous processes can meet the high demands for productivity, profitability and quality.

Experimental Investigation of a New Modular Crusher Machine Developed for Olive Oil Extraction Plants

The crushing system is crucial in the virgin olive oil (VOO) mechanical extraction process. The use of different crusher machines can highly influence the quality of the final product, mainly due to the phenolic and volatile content responsible for VOO sensory and health properties. An experimental investigation was conducted to evaluate the effect of the geometric features of a new model of crusher machine for olives. The crusher machine consists of interchangeable rotors: a rotor with hammers and a rotor with knives. The evaluation was carried out with the same fixed grid in stainless steel with 6 mm diameter circular holes. An evaluation was carried out on the impact of the crusher tools on the pit particle size and on the distribution of energy and temperature. The performance of the plant was also assessed in terms of process efficiency and olive oil quality. The results showed that the specific energy released by the tool per unit of product, calculated through both energy conservation and comminution theory, is about 25–27% higher in the case of hammers. Since the impact energy is mainly dissipated in the product as heat, the temperature reached during milling operations with the hammer crusher was also higher by the same percentage with respect to the knife crusher. This has important consequences on the quality of the product: the new knife rotor used in the crushing phase produced an improvement in VOO quality, relating mainly to sensory attributes and the health-enhancing properties of the final product. The ability of the crusher to break cell walls and vacuoles, thus releasing the oil contained therein, is comparable for the two different rotors.

The Use of a Cooling Crusher to Reduce the Temperature of Olive Paste and Improve EVOO Quality of Coratina, Peranzana, and Moresca Cultivars: Impact on Phenolic and Volatile Compounds

A new technology used to reduce the temperature of olive paste was applied to the extra virgin olive oil (EVOO) mechanical extraction process. The performance of a cooling crusher that was able to counteract the thermal increase that occurs during olive fruit grinding was analyzed to evaluate the effects on the development of volatile compounds and the concentration of hydrophilic phenols in the final product. The volatile profiles and phenolic fraction of EVOOs extracted from three different cultivars (Coratina, Peranzana, and Moresca) were positively affected by the use of lower temperatures during the crushing phase. The volatile fractions showed increases in the total aldehydes, mainly related to the concentrations of (E)-2-hexenal, and reductions in the total alcohols, mainly due to 1-penten-3-ol, 1-hexanol and (Z)-3-hexen-1-ol contents. The use of a lower temperature reduced the level of oxidative processes, protecting the phenolic compounds in the Moresca and Peranzana EVOOs by 17.8 and 12.1%, respectively.

Effects of Ultrasound Technology on the Qualitative Properties of Italian Extra Virgin Olive Oil

The development of innovative technologies in the mechanical extraction process of extra virgin olive oil can improve its quality standards through the modulation of physical, chemical and biochemical processes. Extra virgin olive oil quality and varietal differentiation are influenced by many factors, particularly the extraction. The use of ultrasound technology in the extraction process does not affect the quality, the composition, and the thermal properties of the oil, facilitating its separation from solids, and it allows the release of active compounds from the olive paste, with a positive influence on the phenolic content. In this study, the impact of ultrasound technologies was evaluated on merceological parameters, quality profile, and organoleptic features of extra virgin olive oils extracted from whole and destoned olives of the three main Italian cultivars (i.e., Peranzana, Canino, and Coratina). The parameters analyzed were influenced by both genotype and treatment, in particular, sonication did not lead to significant changes in the nutraceutical profile of the oils. The de-stoned olives were able to determine a great improvement of oil quality both for phenolic and volatile composition with a significant enhancement of health and sensory properties of the product.

Sterols and Triterpene Diols in Virgin Olive Oil: A Comprehensive Review on Their Properties and Significance, with a Special Emphasis on the Influence of Variety and Ripening Degree

Olive oil is considered one of the most valuable vegetable oils and is highly appreciated by consumers for its specific and distinguishable taste and aroma, as well as its nutritional value. Sterols and triterpene diols are important carriers of bioactive properties of olive oil and are responsible for some of the beneficial effects of its consumption on human health, such as lowering serum LDL-cholesterol levels and significantly reducing the risk of cardiovascular diseases. The concentration of total sterols and the proportions of particular sterols and triterpene diols are among the parameters used to verify and prove the authenticity of olive oil in accordance with the EU and other countries’ regulations. Finally, their composition has been shown to have high discrimination potential for ensuring traceability with respect to variety, geographical origin, harvest date, and other factors. For these reasons, the research on sterols and triterpene diols in olive oil is an ever-growing field of scientific interest with great practical importance. This review focuses on all the important aspects of sterols and triterpene diols in olive oil, from their chemical structure, biosynthesis, occurrence and role in plants, health benefits, and their use in official controls of olive oil purity and authenticity, to a conclusive survey on the recent findings about the effects of different factors of influence on their content and composition, with a detailed comparative analysis of studies that investigated the effects of the two most important factors, variety and ripening degree.

A Review on High-Power Ultrasound-Assisted Extraction of Olive Oils: Effect on Oil Yield, Quality, Chemical Composition and Consumer Perception

The objective of this review is to illustrate the state of the art in high-power ultrasound (HPU) application for olive oil extraction with the most recent studies about the effects of HPU treatment on oil yield, quality, chemical composition, as well as on the consumer's perception. All the examined works reported an increase in oil yield and extractability index through the use of HPU, which was ascribed to reduced paste viscosity and cavitation-driven cell disruption. Olive oil legal quality was generally not affected; on the other hand, results regarding oil chemical composition were conflicting with some studies reporting an increase of phenols, tocopherols, and volatile compounds, while others underlined no significant effects to even slight reductions after HPU treatment. Regarding the acceptability of oils extracted through HPU processing, consumer perception is not negatively affected, as long as the marketer effectively delivers information about the positive effects of ultrasound on oil quality and sensory aspect. However, only a few consumers were willing to pay more, and hence the cost of the innovative extraction must be carefully evaluated. Since most of the studies confirm the substantial potential of HPU to reduce processing times, improve process sustainability and produce oils with desired nutritional and sensory quality, this review points out the need for industrial scale-up of such innovative technology.

A Polyphenol-Rich Extract of Olive Mill Wastewater Enhances Cancer Chemotherapy Effects, While Mitigating Cardiac Toxicity

Cardiovascular toxicity remains one of the most adverse side effects in cancer patients receiving chemotherapy. Extra-virgin olive oil (EVOO) is rich in cancer preventive polyphenols endowed with anti-inflammatory, anti-oxidant activities which could exert protective effects on heart cells. One very interesting derivative of EVOO preparation is represented by purified extracts from olive mill waste waters (OMWW) rich in polyphenols. Here, we have investigated the anti-cancer activity of a OMWW preparation, named A009, when combined with chemotherapeutics, as well as its potential cardioprotective activities. Mice bearing prostate cancer (PCa) xenografts were treated with cisplatin, alone or in combination with A009. In an in vivo model, we found synergisms of A009 and cisplatin in reduction of prostate cancer tumor weight. Hearts of mice were analyzed, and the mitochondria were studied by transmission electron microscopy. The hearts of mice co-treated with A009 extracts along with cisplatin had reduced mitochondria damage compared to the those treated with chemotherapy alone, indicating a cardioprotective role. To confirm the in vivo results, tumor cell lines and rat cardiomyocytes were treated with cisplatin in vitro, with and without A009. Another frequently used chemotherapeutic agent 5-fluorouracil (5-FU), was also tested in this assay, observing a similar effect. In vitro, the combination of A009 with cisplatin or 5-FU was effective in decreasing prostate and colon cancer cell growth, while it did not further reduce growth of rat cardiomyocytes also treated with cisplatin or 5-FU. A009 cardioprotective effects towards side effects caused by 5-FU chemotherapy were further investigated, using cardiomyocytes freshly isolated from mice pups. A009 mitigated toxicity of 5-FU on primary cultures of mouse cardiomyocytes. Our study demonstrates that the polyphenol rich purified A009 extracts enhance the effect of chemotherapy in vitro and in vivo, but mitigates chemotherpy adverse effects on heart and on isolated cardiomyocytes. Olive mill waste water extracts could therefore represent a potential candidate for cardiovascular prevention in patients undergoing cancer chemotherapy.

Development of a Pressure Control System According to Paste Rheology for Ultrasound Processing in Industrial Olive Oil Extraction

Recent research has demonstrated how ultrasound can benefit the industrial processing of olive paste before oil extraction. However, the absence of a device for controlling pressure inside the sonication cell is a major hindrance to its application. To address this problem, a pneumatic device with a programmable logic controller was implemented to automatically adjust pressure in the sonication cell according to a preset value: its functionality was tested in industrial oil extraction. An experiment was conducted to compare device performance when applied to olive batches with different solid/liquid ratios and differing rheology. The control system adjusted the flow section of the valve at the outlet of the sonication cell and the mass flow rate of the feed pump in order to maintain the pressure preset by the operator. Results indicate that the pressure was 3.0 ± 0.2 bar, 3.5 ± 0.2 bar, and 4.0 ± 0.2 bar when the set point was 3.0 bar, 3.5 bar, and 4.0 bar, respectively: there was thus no significant difference between controlled and set values. This indicates that the device is able to control pressure inside the sonication cell with a maximum deviation of 0.2 bar. In this case, the sonication intensity was stabilized at 135 W/cm2, 150 W/cm2, and 165 W/cm2 at 3.0 bar, 3.5 bar, and 4.0 bar, respectively. This study presents an advancement in ultrasound applications for industrial olive oil extraction: optimal pressure control in the sonication cell.

Application of Low Temperature during the Malaxation Phase of Virgin Olive Oil Mechanical Extraction Processes of Three Different Italian Cultivars

The malaxation step, one of the most important phases of the virgin olive oil (VOO) mechanical extraction process involved in the development of the main quality characteristics of the final product, was carried out at a low temperature (18 °C). The rapid control of malaxer temperature was handled with the same chiller as that of the heat exchanger used in a semi-industrial extraction plant. Low temperature was used during the full olive paste kneading process and also for half of this process, which showed that there was a significant impact on the phenolic and volatile contents of VOO. Trials were conducted on three different cultivars (Canino, Moraiolo and Peranzana), and their phenolic and volatile concentrations showed different quantitative and qualitative effects due to the prolonged use of low temperature after the crushing phase, as a function of the different genetic origins of the olives. The process of phenolic compound solubilization into the oily phase was negatively influenced by the use of low temperature during the entire malaxation period for all the cultivars, whereas the volatile fraction showed an improvement in VOO flavor mainly due to the oil extracted from Canino olives.

Influence of the Ripening Stage and Extraction Conditions on the Phenolic Fingerprint of 'Corbella' Extra-Virgin Olive Oil

The ancient 'Corbella' olive variety from the center-north of Catalonia is being recovered to obtain quality extra-virgin olive oil (EVOO) with unique organoleptic properties. The aim of this work was to determine the effect of agronomic and technical factors on the phenolic fingerprint of EVOO and to establish the optimum harvesting time and crushing and malaxation conditions for 'Corbella' olives. Therefore, three different ripening indices (0.3, 1.2, and 3.2) and three crushing temperatures (10, 18, and 25 OC) were studied. Additionally, a factorial design to optimize the phenolic concentration of the EVOO was developed, applying a range of sieve diameters (4 and 6 mm), and malaxation time (30 and 60 min) and temperature (27, 32, and 37 °C). The phenolic profile was analyzed by ultra-high performance liquid chromatography coupled to mass spectrometry in a tandem detector. The level of secoiridoids, the major phenolic compounds in the oil, was higher when using olives harvested earlier. Oleuropein aglycone and ligstroside aglycone were degraded during crushing at high temperatures, resulting in the formation of oleacein and oleocanthal. The best processing conditions in terms of total phenolic content were found to be 30 min of malaxation at 37 OC, the crushing size not having any affect.

Assessment of the olive oil extraction plant layout implementing a high-power ultrasound machine

The objective of this study is to assess the effects of installation and operation of a high-power ultrasound machine (HPU) for the treatment of olive paste by using ultrasound technology in order to evaluate the best way installation and the best definition of the operating conditions of the machine. The study was conducted installing in an industrial olive oil mill a continuous processing ultrasound machine, which used a frequency of 20 kHz able to work at 3200 kg h^-1 as feed capacity. Checking of performance has been carried out by the assessment of the different operating and process conditions, assessing in particular the impact of the ultrasound treatment before and after the malaxation phase on performance indicators of the continuous olive oil plant (plant extractability, olive paste rheological characteristic) and on selected chemical properties of the olive oil extracted (quality parameters, antioxidant content, and volatile profiles). In the tested conditions, high-power ultrasound treatment did not produce significant effect on the legal parameters (free acidity, peroxide index and spectrophotometric indexes), while a significant increase in the content of phenolic compounds was generally observed; higher enhancements were more evident when the high-power ultrasound treatment was carried out before the malaxation phase.

Effects of ultrasound and microwave pretreatments on hydrodistillation extraction of essential oils from Kumquat peel

Main objectives of this work were to investigate the influences of ultrasound pretreatment (UP) and microwave pretreatment (MP) on extraction kinetics, chemical composition, and antioxidant activity of Kumquat peel essential oil (EO) obtained by hydrodistillation extraction (HDE). The effects of ultrasound power and processing time, and microwave power and processing time were evaluated. As compared with HDE individually, UP and MP decreased the extraction time, increased the yield and DPPH radical-scavenging activity but did not noticeably affect chemical composition of the EO. For UP and MP, the highest EO yield was obtained when the ultrasonic power and processing time, and microwave power and processing time were 210 W and 30 min, 300 W and 6 min, respectively. In comparison with MP, UP gave a higher yield and DPPH radical-scavenging activity of the EO. Overall, UP and MP are promising techniques for HDE of EO from kumquat peel.

Olive oil consumption and its repercussions on lipid metabolism

Consumption of highly processed foods, such as those high in trans fats and free sugars, coupled with sedentarism and chronic stress increases the risk of obesity and cardiometabolic disorders, while adherence to a Mediterranean diet is inversely associated with the prevalence of such diseases. Olive oil is the main source of fat in the Mediterranean diet. Data accumulated thus far show consumption of extra virgin, (poly)phenol-rich olive oil to be associated with specific health benefits. Of note, recommendations for consumption based on health claims refer to the phenolic content of extra virgin olive oil as beneficial. However, even though foods rich in monounsaturated fatty acids, such as olive oil, are healthier than foods rich in saturated and trans fats, their inordinate use can lead to adverse effects on health. The aim of this review was to summarize the data on olive oil consumption worldwide and to critically examine the literature on the potential adverse effects of olive oil and its main components, particularly any effects on lipid metabolism. As demonstrated by substantial evidence, extra virgin olive oil is healthful and should be preferentially used within the context of a balanced diet, but excessive consumption may lead to adverse consequences.

Impact of Emerging Technologies on Virgin Olive Oil Processing, Consumer Acceptance, and the Valorization of Olive Mill Wastes

There is a growing consumer preference for high quality extra virgin olive oil (EVOO) with health-promoting and sensory properties that are associated with a higher content of phenolic and volatile compounds. To meet this demand, several novel and emerging technologies are being under study to be applied in EVOO production. This review provides an update of the effect of emerging technologies (pulsed electric fields, high pressure, ultrasound, and microwave treatment), compared to traditional EVOO extraction, on yield, quality, and/or content of some minor compounds and bioactive components, including phenolic compounds, tocopherols, chlorophyll, and carotenoids. In addition, the consumer acceptability of EVOO is discussed. Finally, the application of these emerging technologies in the valorization of olive mill wastes, whose generation is of concern due to its environmental impact, is also addressed.

Optimizing extraction method of aroma compounds from grape pomace

Grape pomace is a major wine industry byproduct. Extraction of volatile compounds from grape pomace is rarely explored. A cost-effective method was developed in this study for aroma compounds extraction from grape pomace with the potential for industrial application. Based on the solvent extraction procedure, experimental factors including pretreatment, enzymatic hydrolysis time, solvent concentration and distillation time were investigated to optimize the extraction process. Volatile compounds of the pomace extract were analyzed using headspace solid-phase microextraction gas-chromatography mass spectrometry (HS-SPME-GC-MS) method. Results revealed that enzymatic hydrolysis was the optimal pretreatment method. A maximum extraction efficiency was achieved under 48 hr of enzymatic hydrolysis, 70% of ethanol concentration and 20 min of distillation. A total of 65 volatile compounds were identified in the extract, including 16 alcohols, 1 alkane, 1 aldehyde, 9 esters, 3 ketones, 4 phenols, 6 terpenes, and 1 furan, of which 15 volatiles were determined as odor-active compounds. This study developed a feasible extraction technique to recycle the underutilized byproducts from wine industry to produce aroma/flavor food additives. PRACTICAL APPLICATION: This study develops a cost-effective method for aroma compounds extraction from grape pomace with the potential for industrial application as food additives.

Conservation of Native Wild Ivory-White Olives from the MEDES Islands Natural Reserve to Maintain Virgin Olive Oil Diversity

Food diversity, and in particular genetic diversity, is being lost at an alarming rate. Protection of natural areas is crucial to safeguard the world's threatened species. The Medes Islands (MI), located in the northwest Mediterranean Sea, are a protected natural reserve. Wild olive trees also known as oleasters make up part of the vegetation of the Meda Gran island. Among them, in 2012, a wild albino ivory-white olive tree with fruit was identified. Fruits were collected from this tree and their seeds were first sown in a greenhouse and then planted in an orchard for purposes of ex situ preservation. Seven out of the 78 seedling trees obtained (12%) produced ivory-white fruits. In autumn 2018, fruits from these trees were sampled. Although the fruits had low oil content, virgin olive oil with unique sensory, physicochemical, and stability characteristics was produced. With respect to the polyphenols content, oleacein was the main compound identified (373.29 ± 72.02 mg/kg) and the oleocanthal was the second most abundant phenolic compound (204.84 ± 52.58 mg/kg). Regarding pigments, samples were characterized by an intense yellow color, with 12.5 ± 4.6 mg/kg of chlorophyll and 9.2 ± 3.3 mg/kg of carotenoids. Finally, oleic acid was the main fatty acid identified. This study explored the resources of the natural habitat of the MI as a means of enrichment of olive oil diversity and authenticity of this traditional Mediterranean food.

High vacuum-assisted extraction affects virgin olive oil quality: Impact on phenolic and volatile compounds

High vacuum technology has been incorporated into a new assisted extraction system applied to virgin olive oil (VOO) processing, which was tested at a lab-scale pilot plant to evaluate its impact on the physicochemical properties of the olive paste and oil. The vacuum system induced changes in the mechanical and structural properties of the olive cells, improving the coalescence of the oil droplets due to substantial cellular and intracellular mass transfer during the process, as shown by cryo-scanning electron microscopy (Cryo-SEM) analysis. The effects on the quality characteristics of VOOs extracted from three cultivars at different malaxation temperatures were evaluated. A significant increase in the phenolic content, from 25.2% to 48.6%, was observed. The content of volatile compounds responsible for the VOO flavor decreased as a function of malaxation temperature. The reduction of some volatile molecules related to the VOO off-flavor (ethanol, ethyl acetate and acetic acid) was also shown.

Extraction of Peanut Oil Using Thermosonication: Modeling and Multiobjective Optimization of Process Parameters Using Box-Behnken Design

The extraction of peanut oil was investigated using the combination of ultrasound and heat application, which is known as a novel technology called thermosonication. The study was set up using the Box-Behnken design and the models based on quadratic equations were established. The effects of extraction time (4-12 min), extraction temperature (40-60°C), solvent-to-solid ratio (SSR) (3:1-9:1)(v/w) and ultrasound power (60-100%) on the extraction yield and the oleic acid concentration of extracted oils were investigated. Results showed that the extraction yield was primarily affected by the extraction temperature and SSR. The average maximum yield of 39.93% was achieved when variables were set to 12 min of time, 50°C of temperature, 9:1(v/w) of SSR and 80% of ultrasound power. Thermosonication did not significantly affect the fatty acid composition. Since it was targeted to determine an optimum point where the maximum extraction yield and oleic acid concentration were obtained, a multiobjective optimization was performed. The optimum thermosonication conditions were determined as 4 min of time, 60°C of temperature, 9:1(v/w) of SSR and 100% of power with a maximum extraction yield of 39.86%. Also, the oleic acid concentration was determined as 63.51% in this optimum condition.

Sono-physical and sono-chemical effects of ultrasound: Primary applications in extraction and freezing operations and influence on food components

Ultrasound is an advanced non-thermal food-processing technology that has received increasing amounts of interest as an alternative to, or an adjuvant method for, conventional processing techniques. This review explores the sono-physical and sono-chemical effects of ultrasound on food processing as it reviews two typical food-processing applications that are predominantly driven by sono-physical effects, namely ultrasound-assisted extraction (UAE) and ultrasound-assisted freezing (UAF), and the components modifications to food matrices that can be triggered by sono-chemical effects. Efficiency enhancements and quality improvements in products (and extracts) using ultrasound are discussed in terms of mechanism and principles for a range of food-matrix categories, while efforts to improve existing ultrasound-assist patterns was also seen. Furthermore, the progress of experimental ultrasonic equipments for UAE and UAF as food-processing technologies, the core of the development in food-processing techniques is considered. Moreover, sono-chemical reactions that are usually overlooked, such as degradation, oxidation and other particular chemical modifications that occur in common food components under specific conditions, and the influence on bioactivity, which was also affected by food processing to varying degrees, are also summarised. Further trends as well as some challenges for, and limitations of, ultrasound technology for food processing, with UAE and UAF used as examples herein, are also taken into consideration and possible future recommendations were made.

Pulsed Electric Fields for the Treatment of Olive Pastes in the Oil Extraction Process

The aim of this study was to evaluate the ability of pulsed electric field (PEF) technology to improve the extractability and enhance the oil quality in an industrial olive oil extraction process. Using a PEF device on olive pastes significantly increased the extractability from 79.5% for the control, up to 85.5%. The PEF system did not modify the primary legal quality parameters or total concentrations of phenols, aldehydes, and esters. On the contrary, the non-thermal treatment slightly enhanced the dialdehydic forms of decarboxymethyl elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA) and tyrosol (p-HPEA-EDA), and decreased the total saturated and unsaturated C5 and C6 alcohols of the PEF EVOO (Extra Virgin Olive Oil) compared to the control test. This study confirmed that PEF technology can improve olive oil extraction and quality.

Low-frequency, high-power ultrasound treatment at different pressures for olive paste: Effects on olive oil yield and quality

Ultrasound technology was employed to test its action on the extraction of olive oil at the industrial scale. Because of its mechanical effects, ultrasound waves were applied to the olive paste, between the crushing and malaxing operations. Comparative experiments were performed between traditional extraction processes and the innovative extraction process, with the addition of the ultrasound treatment. Different levels of pressure were tested on olive paste, using four different olive cultivars. Pressure level played an important role in olive oil extractability. When ultrasound was subjected to olive paste with a pressure of about 3.5 bar, there was a significant increase of extractability compared to the traditional process. On the other hand, there was no significant effect between ultrasound treatment and traditional technology on extractability when ultrasound at a pressure level of 1.7 bar was used.

Extra-Virgin Olive Oil Extracted Using Pulsed Electric Field Technology: Cultivar Impact on Oil Yield and Quality

The main operators of the olive oil sector are continuously involved in the development of the olive oil mechanical extraction process with the common aim of increasing both the quality and the oil extraction yield coupled with the potential enhancement of the working efficiency of the olive mill. The pulsed electric field (PEF) is a recently studied technological innovation for the improvement of olive oil extraction technology. The impact of the PEF on the diffusion of oil and microconstituents, determined by the disruption effects on olive cell tissues carried out by the non-thermal method, was evaluated. A PEF can increase the permeability and breaking of the cell membranes with a consequent positive result on oil extractability and quality, mainly related to the compounds involved in the health and sensory properties of extra virgin olive oil. The PEF was tested on three Italian olive cultivars (Carolea, Coratina, and Ottobratica). The results showed a positive impact of the new technology on the oil yield, with an increase ranging from 2.3 to 6%, and on the concentration of hydrophilic phenols, with an increase ranging from 3.2 to 14.3%, with respect to the control tests. The data of the main compounds related to the health and sensory notes also showed high variability as a consequence of the genetic origins of the olive cultivars.

Innovative technologies in virgin olive oil extraction process: influence on volatile compounds and organoleptic characteristics

BACKGROUND

Innovative technologies are experimentally applied to the virgin olive oil extraction process in order to make it continuous and more efficient. Most of the efforts aim at overcoming the limitations of the traditional malaxation step, which, however, is essential for the development of virgin olive oil sensory notes.

RESULTS

Compared to the traditional process, innovative technologies based on the heat exchanger led generally to a decrement in volatile lipoxygenase (LOX) alcohols linked to alcohol dehydrogenase activity and, conversely, to a slightly increase in volatile LOX esters. Aldehydes from the same pathway were not significantly affected. However, an industrial combined plant constructed from a heat exchanger, low-frequency ultrasound device and microwave apparatus determined the highest 'fruity' intensity perceived by panellists, in accordance with the highest value of total volatiles, with values significantly higher than heat exchanger alone, which, instead, had the lowest levels of hexanal and LOX alcohols. The pungent taste showed the same trend observed for 'fruity' intensity, whereas bitter taste did not show significant differences among trials.

CONCLUSION

The introduction of ultrasound, coupled with heat exchanger and microwave, seemed not to modify the behaviour of enzymes of the LOX pathway, and the obtained virgin olive oils showed volatiles and organoleptic characteristics not significantly different from those obtained by the traditional olive oil extraction process. These findings provided the first insights into the effect of the combination of innovative technologies in the olive oil extraction process on virgin olive oil volatiles and sensory characteristics. © 2019 Society of Chemical Industry.