Olive oil and its principal bioactive compound: Hydroxytyrosol – A review of the recent literature

Multienzyme cascade for synthesis of hydroxytyrosol via engineered Escherichia coli

Hydroxytyrosol, a fine chemical, is widely utilized in food and pharmaceutical industries. In this study, we constructed a pathway to produce hydroxytyrosol by co-expressing tyrosin-phenol lyase (TPL), L-amino acid dehydrogenase (aadL), α-keto acid decarboxylase (KAD), aldehyde reductase (yahK) and glucose dehydrogenase (gdh). We changed combinations between plasmids with different copy numbers and target genes, resulting in 84% increase in hydroxytyrosol production. The yield of hydroxytyrosol was further increased 89.3% by optimizing the temperature and pH. Finally, 55.3 mM hydroxytyrosol was produced within 14 h by fed-batch biotransformation. This study provides a novel approach for hydroxytyrosol production.

Hydroxytyrosol: A Promising Therapeutic Agent for Mitigating Inflammation and Apoptosis

Inflammation and apoptosis are interrelated biological processes that have a significant impact on the advancement and growth of certain chronic diseases, such as cardiovascular problems, neurological conditions, and osteoarthritis. Recent research has emphasized that focusing on these mechanisms could result in novel therapeutic approaches that aim to decrease the severity of diseases and enhance patient outcomes. Hydroxytyrosol (HT), which is well-known for its ability to prevent oxidation, has been identified as a possible candidate for regulating both inflammation and apoptosis. In this review, we will highlight the multifaceted benefits of HT as a therapeutic agent in mitigating inflammation, apoptosis, and associated conditions. This review provides a comprehensive overview of the latest in vitro and in vivo research on the anti-inflammatory and antiapoptotic effects of HT and the mechanisms by which it works. Based on these studies, it is strongly advised to use HT as a bioactive ingredient in pharmaceutical products intended for mitigating inflammation, as well as those with apoptosis applications.

The Application of Untargeted Metabolomic Approaches for the Search of Common Bioavailable Metabolites in Human Plasma Samples from Lippia citriodora and Olea europaea Extracts

Lippia citriodora and Olea europaea are known for their shared common bioactivities. Although both matrices are rich in similar families of bioactive compounds, their specific phytochemical compounds are mostly different. Since these compounds can be metabolized in the organism, this study hypothesized that common bioavailable metabolites may contribute to their similar bioactive effects. To test this, an acute double-blind intervention study in humans was conducted with blood samples collected at multiple time points. Using an untargeted metabolomic approach based on HPLC-ESI-QTOF-MS, 66 circulating metabolites were detected, including 9 common to both extracts, such as homovanillic acid sulfate and glucuronide derivates, hydroxytyrosol sulfate, etc. These common metabolites displayed significantly different Tmax values depending on the source, suggesting distinct metabolization pathways for each extract. The study highlights how shared bioavailable metabolites may underlie similar bioactivities observed between these two plant sources.

Inverse metabolic engineering based on metabonomics for efficient production of hydroxytyrosol by Saccharomyces cerevisiae

Metabolic engineering provides a powerful approach to efficiently produce valuable compounds, with the aid of emerging gene editing tools and diverse metabolic regulation strategies. However, apart from the current known biochemical pathway information, a variety of unclear constraints commonly limited the optimization space of cell phenotype. Hydroxytyrosol is an important phenolic compound that serves various industries with prominent health-beneficial properties. In this study, the inverse metabolic engineering based on metabolome analysis was customized and implemented to disclose the hidden rate-limiting steps and thus to improve hydroxytyrosol production in Saccharomyces cerevisiae (S. cerevisiae). The potential rate-limiting steps involved three modules that were eliminated individually via reinforcing and balancing metabolic flow, optimizing cofactor supply, and weakening the competitive pathways. Ultimately, a 118.53 % improvement in hydroxytyrosol production (639.84 mg/L) was achieved by inverse metabolic engineering.

Perception, Knowledge, and Consumption Potential of Crude and Refined Palm Oil in Brazilian Regions

Crude palm oil (CPO) is the most produced vegetable oil globally, with Brazil contributing only 0.74% of global production. Pará and Bahia account for more than 82% of Brazil's output. Despite its widespread use in the food industry after refining, there is little research on CPO consumption and perception in Brazil, particularly regarding its nutritional aspects. This study, conducted between March and July 2022, explored Brazilians' perceptions and the potential for CPO consumption. The results show that most participants are unfamiliar with CPO but view its nutrients favorably. Less than half regularly purchase CPO. Refined palm oil (RPO) is even less known, with many unaware that refining CPO can produce carcinogenic substances. The respondents showed little concern about RPO in their foods, rarely noticing its presence on labels. Despite limited knowledge, participants understand that refining reduces CPO's health benefits, leading to a greater preference for crude oil over refined oil. This study highlights the need for better dissemination of information about CPO in Brazil, emphasizing its nutritional benefits and the importance of adhering to daily lipid intake limits. Adding CPO at the end of cooking or consuming it raw to preserve thermosensitive compounds is also recommended.

Optimization of Phenolic-Enriched Extracts from Olive Leaves via Ball Milling-Assisted Extraction Using Response Surface Methodology

This study aims to extract phenolic-enriched compounds, specifically oleuropein, luteoloside, and hydroxytyrosol, from olive leaves using ball milling-assisted extraction (BMAE). Response surface methodology (RSM) and the Box-Behnken design (BBD) were used to evaluate the effects of the temperature, solvent-to-solid ratio, and milling speed on extraction recovery. The contents of the extract were determined by ultra-high-performance liquid chromatography-mass spectrometry (UPLC-MS) and converted to recoveries to evaluate the extraction efficiency. The optimal extraction conditions for oleuropein, luteoloside, and hydroxytyrosol were identified. Oleuropein had a recovery of 79.0% ± 0.9% at a temperature of 56.4 °C, a solvent-to-solid ratio of 39.1 mL/g, and a milling speed of 429 rpm. Luteoloside's recovery was 74.6% ± 1.2% at 58.4 °C, 31.3 mL/g, and 328 rpm. Hydroxytyrosol achieved 43.1% ± 1.3% recovery at 51.5 °C, 32.7 mL/g, and 317 rpm. The reason for the high recoveries might be that high energy ball milling could reduce the sample size further, breaking down the cell walls of olive leaves, to enhance the mass transfer of these components from the cell to solvent. BMAE is displayed to be an efficient approach to extracting oleuropein, luteoloside, and hydroxytyrosol from olive leaves, which is easy to extend to industrial production.

Neuroprotective Effects of Olive Oil: A Comprehensive Review of Antioxidant Properties

Neurodegenerative diseases are a significant challenge to global healthcare, and oxidative stress plays a crucial role in their development. This paper presents a comprehensive analysis of the neuroprotective potential of olive oil, with a primary focus on its antioxidant properties. The chemical composition of olive oil, including key antioxidants, such as oleuropein, hydroxytyrosol, and oleocanthal, is systematically examined. The mechanisms by which these compounds provide neuroprotection, including counteracting oxidative damage and modulating neuroprotective pathways, are explored. The neuroprotective efficacy of olive oil is evaluated by synthesizing findings from various sources, including in vitro studies, animal models, and clinical trials. The integration of olive oil into dietary patterns, particularly its role in the Mediterranean diet, and its broader implications in neurodegenerative disease prevention are also discussed. The challenges in translating preclinical findings to clinical applications are acknowledged and future research directions are proposed to better understand the potential of olive oil in mitigating the risk of neurodegenerative conditions. This review highlights olive oil not only as a dietary component, but also as a promising candidate in preventive neurology, advocating for further investigation in the context of neurodegenerative diseases.

Comparison of food intake pattern of diabetic patients and healthy individuals in a sample of Saudi population: a case-control study

BACKGROUND

There has been a significant rise in the number of individuals diagnosed with type 2 diabetes mellitus (T2DM), with the condition reaching epidemic proportions globally. This study examined the dietary pattern of a sample of Saudi Arabian adults with T2DM compared to control non-diabetics.

METHODS

Data from 414 participants, 207 control and 207 T2DM was analyzed. Anthropometric measurements, foods intake such as vegetables, fruits, whole grains, fried foods, sweetened juice, sweets, and pastries consumption as well as physical activity were obtained by an interview-survey.

RESULTS

The consumption of vegetables, green and leafy vegetables, starchy vegetables, fruits, proteins, and milk was significantly higher in the diabetics (p< 0.0001 for all and p<0.01 for starchy vegetables). Of the case group, 79.7% of them consumed whole-wheat bread while 54.6% of them consumed low fat milk (p<0.0001). There was a significant decrease in the percentage of cases who consumed discretionary foods and sweetened juices and soft drinks (24.1%), avoided sweets (75.8%) and pastries (37.1%), (p<0.0001). There were also significant increases in the percentages of participants who use healthy fat (as olive oil) in the case group (78.7%) (p<0.001). There was a significant increase in the percentage of diabetics who followed a diet to lose weight (15%) (p<0.05). The majority of the two study groups were physically inactive (control 95.2% & case 94.2%).

CONCLUSIONS

The results of this study provide insight on that diabetics generally follow a healthy diet, yet their engagement in physical activity may not be optimal.

How the "Olive Oil Polyphenols" Health Claim Depends on Anthracnose and Olive Fly on Fruits

Olive anthracnose, caused by Colletotrichum fungi, and the olive fruit fly Bactrocera olea are, respectively, the most important fungal disease and pest affecting olive fruits worldwide, leading to detrimental effects on the yield and quality of fruits and olive oil. This study focuses on the content of hydroxytyrosol (HYT) and its derivatives (the "olive oil polyphenols" health claim) in olive oils extracted from fruits of 'Galega Vulgar' and 'Cobrançosa' cultivars, naturally affected by olive anthracnose and olive fly. The olives, with different damage levels, were harvested from organic rainfed orchards, located in the center of Portugal, at four harvest times over three years. Galega oils extracted from olives with a higher anthracnose and olive fly incidence showed no conformity for the extra virgin olive oil (EVOO) and virgin olive oil (VOO) categories, presenting high acidity and negative sensory notes accompanied by the disappearance of oleacein. Conversely, no sensory defects were observed in Cobrançosa oils, regardless of disease and pest incidence levels, and quality criteria were still in accordance with the EVOO category. The total HYT and tyrosol (TYR) content (>5 mg/20 g) allows for the use of the "olive oil polyphenols" health claim on the label of all the analyzed Cobrançosa olive oils.

Effects of hydroxytyrosol on post-thaw quality of rooster sperm

Semen cryopreservation is one of the most important reproduction techniques in the livestock and poultry industry. Cryopreservation induces cold stress, generating reactive oxygen species (ROS) and oxidative stress causing structural and biochemical damages in sperm. In this study, we evaluated the effects of the hydroxytyrosol (HT), as an antioxidant, at the concentrations of 0, 25, 50, and 100 μg/mL on post-thaw semen quality metrics in rooster. Semen samples were collected twice a week from 10 roosters (29 weeks), processed and frozen according to experimental groups. Different quality parameters, including total motility, progressive motility, viability, morphology, membrane integrity, and malondialdehyde were measured after thawing. Results showed that 25 and 50 μg/mL of HT produced the highest percentage of total motility (51.01 ± 2.19 and 50.15 ± 2.19, respectively) and progressive motility (35.74 ± 1.34 and 35.15 ± 1.34, respectively), membrane integrity (48.00 ± 2.18 and 46.75 ± 2.18, respectively) as well as viability (53.00 ± 2.17 and 52.50 ± 2.17, respectively) compared with the other groups (p < .05). The group with 25 μg/mL of HT showed the lowest significant (p < .05) MDA concentration (1.81 ± 0.25). Our results showed that the effect of HT was not dose-dependent and optimum concentration of HT could improve functional parameters of rooster sperm after freezing-thawing. These findings suggest that HT may have protective effects on the rooster sperm during the freezing-thawing process.

Exploring promising minor natural phenolic compounds in neuroprotection-related preclinical models

Neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, are characterised by the progressive loss of specific neuronal cell populations due to multifactorial factors, including neurochemical and immunological disturbances. Consequently, patients can develop cognitive, motor and behavioural dysfunctions, which lead to impairments in their quality of life. Over the years, studies have reported on the neuroprotective properties inherent in phenolic compounds. Therefore, this review highlights the most recent scientific findings regarding phenolic compounds as promising neuroprotective molecules against neurodegenerative diseases.

Monitoring the Phenolic and Terpenic Profile of Olives, Olive Oils and By-Products throughout the Production Process

Olive oil is a food of great importance in the Mediterranean diet and culture. However, during its production, the olive oil industry generates a large amount of waste by-products that can be an important source of bioactive compounds, such as phenolic compounds and terpenes, revalorizing them in the context of the circular economy. Therefore, it is of great interest to study the distribution and abundance of these bioactive compounds in the different by-products. This research is a screening focused on phytochemical analysis, with particular emphasis on the identification and quantification of the phenolic and terpenic fractions. Both the main products of the olive industry (olives, olive paste and produced oil) and the by-products generated throughout the oil production process (leaf, "alpeorujo", liquid and solid residues generated during decanting commonly named "borras" and washing water) were analyzed. For this purpose, different optimized extraction procedures were performed for each matrix, followed by high-performance liquid chromatography coupled with electrospray time-of-flight mass spectrometry (HPLC-ESI-TOF/MS) analysis. Although no phenolic alcohols were quantified in the leaf and the presence of secoiridoids was low, this by-product was notable for its flavonoid (720 ± 20 µg/g) and terpene (5000 ± 300 µg/g) contents. "Alpeorujo" presented a complete profile of compounds of interest, being abundant in phenolic alcohols (900 ± 100 µg/g), secoiridoids (4500 ± 500 µg/g) and terpenes (1200 ± 100 µg/g), among others. On the other hand, while the solid residue of the borras was the most abundant in phenolic alcohols (3700 ± 200 µg/g) and secoiridoids (680 ± 20 µg/g), the liquid fraction of this waste was notable for its content of elenolic acid derivatives (1700 ± 100 µg/mL) and phenolic alcohols (3000 ± 300 µg/mL). Furthermore, to our knowledge, this is the first time that the terpene content of this by-product has been monitored, demonstrating that it is an important source of these compounds, especially maslinic acid (120 ± 20 µg/g). Finally, the phytochemical content in wash water was lower than expected, and only elenolic acid derivatives were detected (6 ± 1 µg/mL). The results highlighted the potential of the olive by-products as possible alternative sources of a wide variety of olive bioactive compounds for their revalorization into value-added products.

Oleacein: A comprehensive review of its extraction, purification, absorption, metabolism, and health effects

Extra virgin olive oil (EVOO) consumption reduces the risk of cardiovascular disease in high-risk groups and the polyphenols in EVOO play an important health effect on it. As one of the most abundant polyphenols in EVOO, oleacein (OLEA) has many health benefits. However, there is no review article that focus comprehensively on OLEA, and most articles have limited data and information on OLEA. The purpose of this review is to summarize the results of all available studies, to present and compare the main traditional and novel techniques for the extraction and isolation and purification of OLEA, to elucidate the absorption and metabolic pathways of OLEA, and finally, to illustrate the health-promoting properties. Hopefully, this review can promote the use of OLEA in functional foods and therapeutic fields.

Preparation of Complementary Food for Infants and Young Children with Beef Liver: Process Optimization and Storage Quality

In this study, fuzzy mathematics and response surface modeling were applied to optimize the preparation process of beef liver paste and characterize the proximate composition, sensory and physicochemical qualities, and in vitro simulated digestive properties while refrigerated at 0-4 °C (0, 3, 7, 15, 30, 45, and 60 days). The results showed that the optimal preparation process was 4.8% potato starch, 99.4% water, 10.2% olive oil, and a 3:2 ratio of chicken breast and beef liver. The beef liver paste prepared contained essential amino acids for infants and children, with a protein content of 10.29 g/100 g. During storage, the pH of the beef liver paste decreased significantly (p < 0.05) on day 7, texture and rheological properties decreased significantly after 30 days, a* values increased, L* and b* values gradually decreased, and TVB-N and TBARS values increased significantly (p < 0.05) on day 7 but were below the limit values during the storage period (TVB-N value ≤ 15 mg/100 g, TBARS value ≤ 1 mg/Kg). In vitro simulated digestion tests showed better digestibility and digestive characteristics in the first 15 days. The results of this study provide a reference for the development of beef liver products for infant and child supplementation.

Olive Oil Benefits from Sesame Oil Blending While Extra Virgin Olive Oil Resists Oxidation during Deep Frying

Fresh potatoes were deep-fried in olive oil (OO), extra virgin olive oil (EVOO), and their blends with 5%, 10%, and 20% v/v sesame oil (SO). This is the first report on the use of sesame oil as a natural source of antioxidants during olive oil deep frying. The oil was evaluated for anisidine value (AV), free fatty acids (FFAs), extinction coefficient (K₂₃₂ and K₂₇₀), Trolox equivalent antioxidant capacity (TEAC), and total phenols (TPs) until the total polar compounds (TPCs) reached 25%. Sesame lignan transformations were monitored through reversed-phase HPLC. While the TPCs in olive oils increased at a steady rate, the addition of 5%, 10%, and 20% v/v SO delayed TPCs' formation for 1, 2, and 3 h, respectively. The addition of 5%, 10%, and 20% v/v SO increased the olive oil frying time by 1.5 h, 3.5 h, and 2.5 h, respectively. The addition of SO to OO reduced the secondary oxidation products' formation rate. The AV for EVOO was lower than OO and all tested blends, even those with EVOO. EVOO was more resistant to oxidation than OO, as measured by the TPCs and TEAC, while the frying time rose from 21.5 to 25.25 h when EVOO replaced OO. The increase in frying time for OO but not for EVOO, after SO addition, points to a niche market for EVOO in deep frying.

Effect of Heating Temperature of High-Quality Arbequina, Picual, Manzanilla and Cornicabra Olive Oils on Changes in Nutritional Indices of Lipid, Tocopherol Content and Triacylglycerol Polymerization Process

The aim of the study was to determine the stability and heat resistance of extra premium olive oil. The study material consisted of six extra virgin olive oils (EVOO) obtained from Spain. Four samples were single-strain olive oils: Arbequina, Picual, Manzanilla, and Cornicabra. Two samples were a coupage of Arbequina and Picual varieties: Armonia (70% Arbequina and 30% Picual) and Sensation (70% Picual and 30% Arbequina). Olive oil samples were heated at 170 °C and 200 °C in a pan (thin layer model). In all samples, changes in indexes of lipid nutritional quality (PUFA/SFA, index of atherogenicity, index of thrombogenicity, and hypocholesterolemic/hypercholesterolemic ratio), changes in tocopherol, total polar compounds content, and triacylglycerol polymers were determined. Heating olive oil in a thin layer led to its degradation and depended on the temperature and the type of olive oil. Increasing the temperature from 170 to 200 °C resulted in significantly higher degradation of olive oil. At 200 °C, deterioration of lipid nutritional indices, total tocopherol degradation, and formation of triacylglycerol polymers were observed. A twofold increase in the polar fraction was also observed compared to samples heated at 170 °C. The most stable olive oils were Cornicabra and Picual.

Rapid pretreatment-free evaluation of antioxidant capacity in extra virgin olive oil using a laser-nanodecorated electrochemical lab-on-strip

An electroanalytical lab-on-a-strip device for the direct extra-virgin olive oil (EVOO) antioxidant capacity evaluation is proposed. The lab-made device is composed of a CO₂ laser nanodecorated sensor combined with a cutter-plotter molded paper-strip designed for EVOOs sampling and extraction. Satisfactory performance towards the most representative o-diphenols of EVOOs i.e., hydroxytyrosol (HY) and oleuropein (OL) were achieved; good sensitivity (LOD_HY = 2 µM; LOD_OL = 0.6 µM), extended linear ranges (HY: 10-250 µM; OL: 2.5-50 µM) and outstanding reproducibility (RSD < 5%, n = 3) were obtained in rectified oil. The device was challenged for the extraction-free analysis of 15 different EVOO samples, with satisfactory recoveries (90-94%; RSD < 5%, n = 3) and correlation with classical photometric assays (r ≥ 0.91). The proposed device includes all analysis steps, needs 4 µL of sample, and returns reliable results in 2 min, resulting portable and usable with a smartphone.

A comprehensive comparison of Chinese olive oils from different cultivars and geographical origins

China has become increasingly interested in producing olive oil in recent years. In this study, we determined the characteristics of virgin olive oil in five typical cultivars (cv. 'Arbequina,' 'Coratina,' 'Ezhi 8,' 'Frantoio,' and 'Koroneiki') from two of the most suitable production areas for olive cultivation in China. In addition, linear discriminant analysis (LDA) was used to differentiate oils originating from various cultivars and geographical origins. Heatmap was also constructed to describe the differences straightly. Compared to Xichang oils, Longnan oils generally contained higher levels of C18:0, lignans, total esters and total furans, and lower levels of phenolic acids and phenolic alcohols. A variety of cultivars differed in total sterols, hydroxytyrosol derivatives, and volatile compounds. Coratina oils showed excellent properties in two regions. Our findings are closely related to select the optimum olive cultivars in different regions to promote the development of Chinese olive industry scientifically.

Effects of Hydroxytyrosol in Endothelial Functioning: A Comprehensive Review

Pharmacologists have been emphasizing and applying plant and herbal-based treatments in vascular diseases for decades now. Olives, for example, are a traditional symbol of the Mediterranean diet. Hydroxytyrosol is an olive-derived compound known for its antioxidant and cardioprotective effects. Acknowledging the merit of antioxidants in maintaining endothelial function warrants the application of hydroxytyrosol in endothelial dysfunction salvage and recovery. Endothelial dysfunction (ED) is an impairment of endothelial cells that adversely affects vascular homeostasis. Disturbance in endothelial functioning is a known precursor for atherosclerosis and, subsequently, coronary and peripheral artery disease. However, the effects of hydroxytyrosol on endothelial functioning were not extensively studied, limiting its value either as a nutraceutical supplement or in clinical trials. The action of hydroxytyrosol in endothelial functioning at a cellular and molecular level is gathered and summarized in this review. The favorable effects of hydroxytyrosol in the improvement of endothelial functioning from in vitro and in vivo studies were scrutinized. We conclude that hydroxytyrosol is capable to counteract oxidative stress, inflammation, vascular aging, and arterial stiffness; thus, it is beneficial to preserve endothelial function both in vitro and in vivo. Although not specifically for endothelial dysfunction, hydroxytyrosol safety and efficacy had been demonstrated via in vivo and clinical trials for cardiovascular-related studies.

Phenylboronic Acid-Grafted Chitosan Nanocapsules for Effective Delivery and Controllable Release of Natural Antioxidants: Olive Oil and Hydroxytyrosol

Olives and virgin olive oil (VOO) are a staple of Mediterranean diets and are rich in several beneficial phenolic compounds, including hydroxytyrosol (HT). Therefore, VOO was extracted from Koroneiki olive fruits, and its volatile as well as phenolic components were identified. Meanwhile, in order to upgrade the pharmaceutical capabilities of VOO and HT, a new conjugate phenylboronic acid-chitosan nanoparticles (PBA-CSNPs, NF-1) was fabricated and applied as nanocapsules for implanting high loading and efficient delivery of VOO and HT nanoformulations (NF-2 and NF-3). Due to the H-bonding interactions and boronate ester formation between the hydroxyl groups of the phenolic content of VOO or HT and the PBA groups in the nanocapsules (NF-1), VOO and HT were successfully loaded into the PBA-CSNPs nanocapsules with high loading contents and encapsulation efficacies. The NF-2 and NF-3 nanoformulations demonstrated physicochemical stability, as revealed by their respective zeta potential values, and pH-triggered drug release characteristics. The in vitro studies demonstrated that the nascent nanocapsules were almost completely nontoxic to both healthy and cancer cells, whereas VOO-loaded (NF-2) and HT-loaded nanocapsules (NF-3) showed efficient anti-breast cancer efficiencies. In addition, the antimicrobial and antioxidant potentials of VOO and HT were significantly improved after nanoencapsulation.

De Novo Production of Hydroxytyrosol by Saccharomyces cerevisiae-Escherichia coli Coculture Engineering

Hydroxytyrosol is a valuable plant-derived phenolic compound with excellent pharmacological activities for application in the food and health care industries. Microbial biosynthesis provides a promising approach for sustainable production of hydroxytyrosol via metabolic engineering. However, its efficient production is limited by the machinery and resources available in the commonly used individual microbial platform, for example, Escherichia coli, Saccharomyces cerevisiae. In this study, a S. cerevisiae-E. coli coculture system was designed for de novo biosynthesis of hydroxytyrosol by taking advantage of their inherent metabolic properties, whereby S. cerevisiae was engineered for de novo production of tyrosol based on an endogenous Ehrlich pathway, and E. coli was dedicated to converting tyrosol to hydroxytyrosol by use of native hydroxyphenylacetate 3-monooxygenase (EcHpaBC). To enhance hydroxytyrosol production, intra- and intermodule engineering was employed in this microbial consortium: (I) in the upstream S. cerevisiae strain, multipath regulations combining with a glucose-sensitive GAL regulation system were engineered to enhance the precursor supply, resulting in significant increase of tyrosol production (from 17.60 mg/L to 461.07 mg/L); (II) Echpabc was overexpressed in the downstream E. coli strain, improving the conversion rate of tyrosol to hydroxytyrosol from 0.03% to 86.02%; (III) and last, intermodule engineering with this coculture system was performed by optimization of the initial inoculation ratio of each population and fermentation conditions, achieving 435.32 mg/L of hydroxytyrosol. This S. cerevisiae-E. coli coculture strategy provides a new opportunity for de novo production of hydroxytyrosol from inexpensive feedstock.

Maternal Supplementation with Polyphenols and Omega-3 Fatty Acids during Pregnancy: Prenatal Effects on Fetal Fatty Acid Composition in the Iberian Pig

Simple Summary

The present study aimed to determine the effects of maternal dietary supplementation combining hydroxytyrosol and n3 polyunsaturated fatty acids (n3-PUFA) from day 35 to day 100 of gestation on the fatty acid (FA) composition of the offspring tissues of the Iberian pig. No effects were found in the plasma FA composition of the dams but higher levels of n3-PUFA were found in the plasma and different tissues (muscle, liver, and brain) of the supplemented fetuses. These findings may have important implications for piglets’ health and may offer guidance for achieving human dietary n3-PUFA recommendations.

Abstract

Intrauterine Growth Restriction (IUGR) is a major problem in pig production and different strategies, mainly maternal supplementation with different agents, are currently being studied. The combination of hydroxytyrosol and n3-PUFA seems to be a promising treatment to counteract IUGR, since the combination may help improve n3-PUFA composition and lower the inflammatory status of IUGR piglets. The aim of the present study is to determine the effects of a maternal supplementation, from day 35 to day 100 of pregnancy, with linseed oil and hydroxytyrosol on the fetal FA composition. The results showed higher n3 levels, including eicosapentaenoic and docosahexaenoic FA in the offspring from treated gilts, which showed lower n6-PUFA/n3-PUFA (n6/n3) ratios. Saturated and monounsaturated fatty acids were also affected by treatment, especially in the muscle and brain. Thus, a maternal supplementation with linseed oil and hydroxytyrosol affected the fetal FA tissue composition, which could have implications in pig production due to the improvement of the piglets’ health status.

Oleuropein-Enriched Extract From Olive Mill Leaves by Homogenizer-Assisted Extraction and Its Antioxidant and Antiglycating Activities

Olive oil consumption has increased in the last two decades and consequently, its wastes have increased, which generates a tremendous environmental impact. Among the by-products are the olive mill leaves, which are easier and inexpensive to treat than other olive by-products. However, little research has been done on their chemical composition and potential bioactivity. Hence, in this study, olive mill leaves were used to obtain Oleuropein-Enriched Extracts (OLEU-EE) using Conventional Extraction, Ultrasound-Assisted Extraction, and Homogenization-Assisted Extraction. These three techniques were evaluated using a Factorial Design to determine the parameters to obtain an OLEU-EE with high contents of Total Phenolic Compounds (TPC), Antioxidant Activity (AA), and Oleuropein concentration (OLEU). From the results, the Homogenizer-Assisted Extraction (HAE) technique was selected at 18,000 rpm, solid:liquid ratio 1:10, and 30 s of homogenization with 70% ethanol, due to its high TPC (5,196 mg GA/100 g), AA (57,867 μmol of TE/100 g), and OLEU (4,345 mg of OLEU/100 g). In addition, the antiglycating effect of OLEU-EE on the levels of (1) fluorescent Advanced Glycation End Products (AGEs) were IC50 of 0.1899 and 0.1697 mg/mL for 1λEXC 325/λEM 440 and 2λEXC 389/λEM 443, respectively; (2) protein oxidative damage markers such as dityrosine (DiTyr), N-formylkynurenine (N-formyl Kyn), and kynurenine (Kyn) were IC50 of 0.1852, 0.2044, and 0.1720 mg/mL, respectively. In conclusion, OLEU-EE from olive mill leaves has different capacities to inhibit AGEs evidenced by the IC50 of fluorescent AGEs and protein oxidation products, together with the scavenging free radical evidenced by the concentration of Trolox Equivalent. Therefore, OLEU-EE could be potential functional ingredients that prevent oxidative damage caused by free radicals and AGEs accumulation.

De Novo Production of Hydroxytyrosol by Metabolic Engineering of Saccharomyces cerevisiae

Hydroxytyrosol is an olive-derived phenolic compound of increasing commercial interest due to its health-promoting properties. In this study, a high-yield hydroxytyrosol-producing Saccharomyces cerevisiae cell factory was established via a comprehensive metabolic engineering scheme. First, de novo biosynthetic pathway of hydroxytyrosol was constructed in yeast by gene screening and overexpression of different phenol hydroxylases, among which paHD (from Pseudomonas aeruginosa) displayed the best catalytic performance. Next, hydroxytyrosol precursor supply was enhanced via a multimodular engineering approach: elimination of tyrosine feedback inhibition through genomic integration of aro4^K229L and aro7^G141S, construction of an aromatic aldehyde synthase (AAS)-based tyrosine metabolic pathway, and redistribution of metabolic flux between glycolytic pathway and pentose phosphate pathway (PPP) by introducing the exogenous gene Bbxfpk^opt. As a result, the titer of hydroxytyrosol was improved by 6.88-fold. Finally, a glucose-responsive dynamic regulation system based on GAL80 deletion was implemented, resulting in the final hydroxytyrosol yields of 308.65 mg/L and 167.98 mg/g cell mass, the highest known from de novo production in S. cerevisiae to date.

Integration of Nanofiltration and Reverse Osmosis Technologies in Polyphenols Recovery Schemes from Winery and Olive Mill Wastes by Aqueous-Based Processing

More sustainable waste management in the winery and olive oil industries has become a major challenge. Therefore, waste valorization to obtain value-added products (e.g., polyphenols) is an efficient alternative that contributes to circular approaches and sustainable environmental protection. In this work, an integration scheme was purposed based on sustainable extraction and membrane separation processes, such as nanofiltration (NF) and reverse osmosis (RO), for the recovery of polyphenols from winery and olive mill wastes. Membrane processes were evaluated in a closed-loop system and with a flat-sheet membrane configuration (NF270, NF90, and Duracid as NF membranes, and BW30LE as RO membrane). The separation and concentration efficiency were evaluated in terms of the total polyphenol content (TPC), and by polyphenol families (hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids), using high-performance liquid chromatography. The water trans-membrane flux was dependent on the trans-membrane pressure for the NF and RO processes. NF90 membrane rejected around 91% of TPC for the lees filters extracts while NF270 membrane rejected about 99% of TPC for the olive pomace extracts. Otherwise, RO membranes rejected more than 99.9% of TPC for both types of agri-food wastes. Hence, NF and RO techniques could be used to obtain polyphenol-rich streams, and clean water for reuse purposes.

Nanoencapsulation of hydroxytyrosol in chitosan crosslinked with sodium bisulfate tandem ultrasonication: Techno-characterization, release and antiproliferative properties

This research includes production of chitosan nanocapsules through ionic gelation with sodium bisulfate for nanoencapsulation of hydroxytyrosol (HT) using ultrasonication in tandem. The resulting nanocapsules encapsulating HT were analyzed for particle size, ζ-potential, packaging characteristics, FESEM, ATR-FTIR, XRD, DSC, in vitro release, antioxidant potential and antiproliferative properties. The nanocapsules (size 119.50-365.21 nm) were spherical to irregular shaped with positive ζ-potential (17.50-18.09 mV). The encapsulation efficiency of 5 mg/g HT (HTS1) and 20 mg/g HT (HTS2) was 77.13% and 56.30%, respectively. The nanocapsules were amorphous in nature with 12.34% to 15.48% crystallinity and crystallite size between 20 nm and 27 nm. Formation of nanocapsules resulted in increasing the glass transition temperature. HTS2 delivered 67.12% HT (HTS1 58.89%) at the end of the simulated gastrointestinal digestion. The nanoencapsulated HT showed higher antioxidant and antiproliferative (against A549 and MDA-MB-231 cancer cell lines) properties than the free HT.

Fatty Acid Hydroxytyrosyl Esters of Olive Oils Are Bioaccessible According to Simulated In Vitro Gastrointestinal Digestion: Unraveling the Role of Digestive Enzymes on Their Stability

Recently, new bioactive compounds were identified in olive oil, lipophenols, which are composed of a fatty acid (FA) and a phenolic core, such as HT (HT-FA). However, their bioaccessibility remains unknown. Thus, the present study uncovers the impact of the separate phases of gastrointestinal digestion on the release and stability of HT-FAs from oily matrices under in vitro simulated conditions. Accordingly, it was found that the bioaccessibility of HT derivatives is largely dependent on the type of FA that esterifies HT, as well as the food matrix. Also, the generation of HT-FAs during intestinal digestion was observed, with pancreatin being the enzyme responsible, to a higher extent, for the de novo formation of lipophenolic derivatives. These findings prompt us to identify new applications to oily matrices and their byproducts as potential functional ingredients for the promotion of health, where the possible formation of new lipophenols during digestion should be taken into consideration.

Sequential Extraction of Hydroxytyrosol, Mannitol and Triterpenic Acids Using a Green Optimized Procedure Based on Ultrasound

Olive-derived biomasses contain bioactive compounds with health promoting effects as well as antioxidant and sweet-tasting properties. However, their sequential extraction has not been attained. In the present study, firstly antioxidants and mannitol were extracted from exhausted olive pomace (EOP) by an eco-friendly method, ultrasound-assisted water extraction (UAWE). The amplitude (20-80%), extraction time (2-18 min) and solid loading (2-15%, w/v) were evaluated according to a Box-Behnken experimental design. Using the response surface methodology, the optimal conditions for extraction were obtained: 80% amplitude, 11.5% solid loading and 16 min. It enabled the multi-response optimization of the total phenolic content (TPC) (40.04 mg/g EOP), hydroxytyrosol content (6.42 mg/g EOP), mannitol content (50.92 mg/g EOP) and antioxidant activity (ferric reducing power or FRAP, 50.95 mg/g EOP; ABTS, 100.64 mg/g EOP). Moreover, the phenolic profile of the extracts was determined by liquid chromatography-UV and mass spectrometry, identifying hydroxytyrosol as the main phenolic compound and other minor derivatives could be characterized. Scanning electron microscopy was used to analyze the morphological changes produced in the cellular structure of EOP after UAWE. In addition, the chemical composition of the extracted EOP solid was characterized for further valorization. Then, a second extraction step was performed in order to extract bioactive triterpenes from the latter solid. The triterpenes content in the extract was determined and the effect of the previous UAWE step on the triterpenes extraction was evaluated. In this case, the use of ultrasound enhanced the extraction of maslinic acid and oleanolic acid from pelletized EOP with no milling requirement. Overall, UAWE can be applied to obtain antioxidant compounds and mannitol as first extraction step from pelletized EOP while supporting the subsequent recovery of triterpenic acids.

Extra Virgin Olive Oil consumption from Mild Cognitive Impairment patients attenuates oxidative and nitrative stress reflecting on the reduction of the PARP levels and DNA damage

Oxidative/nitrative stress that results from the unbalance of the overproduction/clearance of reactive oxygen/nitrogen species (ROS/NOS), originated from a variety of endo- and/or exo-genous sources, can have detrimental effects on DNA and is involved in Alzheimer's disease (AD) pathology. An excellent marker of oxidative DNA lesions is 8-hydroxy-2'-deoxyguanosine (8-OHdG) while of nitrative stress the enzyme NOS2 (Nitric oxide synthase 2). Under massive oxidative stress, poly(ADP-ribose)polymerase 1 (PARP-1) enzyme activity, responsible for restoration of DNA damage, is augmented, DNA repair enzymes are recruited, and cell survival/or death is ensued through PARP-1 activation, which is correlated positively with neurodegenerative diseases. In this biochemical study the levels of PARP-1, 8-oxo-dG, and NOS2, Aβ1-42, and p-tau in their sera determined using Enzyme-Linked Immunosorbent Assay (ELISA). Patients diagnosed with Mild Cognitive Impairment participated in MICOIL clinical trial, were daily administered with 50 ml Extra Virgin Olive Oil (EVOO) for one year. All MCI patients' biomarkers that had consumed EVOO were tantamount to those of healthy participants, contrary to MCI patients who were not administered. EVOO administration in MCI patients resulted in the restoration of DNA damage and of the well-established "hallmarks" AD biomarkers, thanks probably to its antioxidant properties exhibiting a therapeutic potentiality against AD. Molecular docking simulations of the EVOO constituents on the crystal structure of PARP-1 and NOS-2 target enzymes were also employed, to study in silico the ability of the compounds to bind to these enzymes and explain the observed in vitro activity. In silico analysis has proved the binding of EVOO constituents on PARP-1and NOS-2 enzymes and their interaction with crucial amino acids of the active sites. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT03362996. MICOIL GOV IDENTIFIER: NCT03362996.

Health benefits of first and second extraction drum-dried pitted olive pomace

Olive pomace (OP) is the main by-product of olive oil extraction. After pit and skin removal, OP pulp has high concentrations of dietary fiber and phenolics with high antioxidant capacity. This study evaluated mice health benefits of drum-dried pitted OP pulp obtained after first and second oil extraction. Fresh OP was steam blanched, then pits and skins separated in a pulper/finisher, and pulp drum-dried and milled. OP was characterized by proximate analysis, total soluble phenolics (TSP), individual phenolics, and dietary fiber. Drum-dried pitted OP from first and second extraction was formulated at 10% and 20% in a high fat mice diet. Low fat (5%) and high fat (18%) control diets were also used for comparison. First extraction OP had higher TSP than OP from second extraction. Hydroxytyrosol was the main phenolic in OP. Mice weight gain was lower for the four OP diets compared to high and low-fat control diets. Fecal protein was high for all OP diets, indicating poor protein retention in mice, possibly by phenolics binding of protein and enzymes. Liver weight and adipose tissue were lower in mice consuming the four high fat OP diets compared to high fat control diet. Also, there was no effect on blood glucose by OP in diets. Mice gut microbiota analysis indicated that Actinobacteria decreased in the OP diets compared to the two control diets while Bacteroidetes increased, indicating a positive correlation with reduced body fat and weight. Drum-dried pitted OP is a novel agricultural by-product with its bioactive compounds having the potential to be incorporated in feeds and foods providing health benefits. PRACTICAL APPLICATION: Drum-dried pitted olive pomace can be produced from first or second olive oil extraction byproducts to be used as a shelf-stable healthy food or feed supplement.

Co-Processed Olive Oils with Thymus mastichina L.-New Product Optimization

Olive co-processing consists of the addition of ingredients either in the mill or in the malaxator. This technique allows selecting the type of olives, the ingredients with the greatest flavoring and bioactive potential, and the technological extraction conditions. A new product-a gourmet flavored oil-was developed by co-processing olives with Thymus mastichina L. The trials were performed using overripe fruits with low aroma potential (cv. 'Galega Vulgar'; ripening index 6.4). Experimental conditions were dictated by a central composite rotatable design (CCRD) as a function of thyme (0.4-4.6%, w/w) and water (8.3-19.7%, w/w) contents used in malaxation. A flavored oil was also obtained by adding 2.5% thyme during milling, followed by 14% water addition in the malaxator (central point conditions of CCRD). The chemical characterization of the raw materials, as well as the analysis of the flavored and unflavored oils, were performed (chemical quality criteria, sensory analysis, major fatty acid composition, and phenolic compounds). Considering chemical quality criteria, the flavored oils have the characteristics of "Virgin Olive Oil" (VOO), but they cannot have this classification due to legislation issues. Flavored oils obtained under optimized co-processing conditions (thyme concentrations > 3.5-4.0% and water contents varying from 14 to 18%) presented higher phenolic contents and biologic value than the non-flavored VOO. In flavored oils, thyme flavor was detected with high intensity, while the defect of "wet wood", perceived in VOO, was not detected. The flavored oil, obtained by T. mastichina addition in the mill, showed higher oxidative stability (19.03 h) than the VOO and the co-processed oil with thyme addition in the malaxator (14.07 h), even after six-month storage in the dark (16.6 vs. 10.3 h).

Fatty acid profile and safety aspects of the edible oil prepared by artisans' at small-scale agricultural companies

The aim of this study was to analyze the fatty acid (FA) profiles and mycotoxin and polycyclic aromatic hydrocarbon (PAH) concentrations in sea buckthorn (SB1, SB2), flaxseed (FL3, FL4, FL5), hempseed (HE6, HE7, HE8), camelina (CA9, CA10), and mustard (MU11) edible oils, prepared by artisans' by artisanal at small-scale agricultural companies in Lithuania. The dominant FAs were palmitic and oleic acids in SB; palmitic, stearic, oleic, linoleic, and α-linolenic acids in FL; palmitic, stearic, oleic, linoleic, and α-linolenic acids in HE; palmitic, oleic, linoleic, α-linolenic, eicosenoic, and erucic acids in CA; and oleic, linoleic, α-linolenic, eicosenoic, and erucic acids in MU. In SB2 oil samples, T-2 toxin and zearalenone concentrations higher than 1.0 µg/kg were found (1.7 and 3.0 µg/kg, respectively). In sample FL4, an ochratoxin A concentration higher than 1.0 µg/kg was established (1.2 µg/kg); also, in HE8 samples, 2.0 µg/kg of zearalenone was found. None of the tested edible oils exceeded the limits for PAH concentration. Finally, because of the special place of edible oils in the human diet, not only should their contamination with mycotoxins and PAHs be controlled but also their FA profile, as an important safety characteristic, must be taken into consideration to ensure higher safety standards.

Topical Almond Oil for Prevention of Pressure Injuries: A Single-Blinded Comparison Study

PURPOSE

The aim of our study was to determine the effect of topical almond oil for prevention of pressure injuries.

DESIGN

Single-blind randomized clinical trial.

SAMPLE AND SETTING

Patients admitted to an intensive care unit in Besat Hospital, Hamadan, Iran, were invited to participate in the trial. Data were collected over an 8-month period.

METHODS

A convenience sample of 108 patients, using a permuted block randomization method was assigned to 3 equal groups that received the intervention almond oil, placebo (liquid paraffin), or control (standard of care). Data included demographic information, Braden Scale score, and National Pressure Ulcer Advisory Panel-European Pressure Ulcer Advisory Panel (NPUAP-EPUAP) pressure injury staging system classification score. The intervention and placebo groups received daily application of 6.5 cc of topical almond oil or paraffin to the sacrum, heels, and shoulders for 7 consecutive days. The skin was evaluated for pressure injuries by an expert nurse who was blinded to groups. Chi-square test, analysis of variance, and regression analyses were used to evaluate relationships within and between groups for study variables, incidence of pressure injuries, and duration of time of onset of pressure injuries. P values less than .05 were deemed statistically significant.

RESULTS

The incidence of pressure injury in the almond oil group (n = 2; 5.6%) was lower than that in the placebo (n = 5; 13.9%, P = .189) or control groups (n = 9; 25.1%, P = .024). The incidence of pressure injuries in the control group was 6.8 and 2.12 (P = .227) times higher than that in the almond and placebo groups, respectively. The onset day of a pressure injury occurred 5.4 days after initiation of the protocol in the almond oil group compared to 4.22 days in the control group (P = .023) and 5 days in the placebo group (P = .196).

CONCLUSION

The topical application of almond oil was associated with a lower incidence of pressure injuries and that developed later during the study compared to participants who received paraffin or standard of care only. Further study is recommended to advance this work in populations at risk for pressure injury.

LC-ESI-LTQ-Orbitrap-MS for Profiling the Distribution of Oleacein and Its Metabolites in Rat Tissues

The purpose of this work was to study the distribution of oleacein (OLEA) and its metabolites in rat plasma and different tissues, namely brain, heart, kidney, liver, lung, small intestine, spleen, stomach, skin, and thyroid, following the acute intake of a refined olive oil containing 0.3 mg/mL of OLEA. For this purpose, a distribution kinetics study was carried out. The plasma and tissues were collected at 1, 2, and 4.5 h after the intervention, and analyzed by LC-ESI-LTQ-Orbitrap-MS. Unmetabolized OLEA was detected in the stomach, small intestine, liver, plasma and, most notably, the heart. This finding may be useful for the development of new applications of OLEA for cardiovascular disease prevention. Noteworthy are also the high levels of hydroxytyrosol (OH-TY) and OLEA + CH₃ found in the small intestine, liver, and plasma, and the detection of nine OLEA metabolites, five of them arising from conjugation reactions. Liver, heart, spleen, and lungs were the target tissues where the metabolites were most distributed. However, it is important to note that OH-TY, in our experimental conditions, was not detected in any target tissue (heart, spleen, thyroids, lungs, brain, and skin). These results shed further light on the metabolism and tissue distribution of OLEA and contribute to understanding the mechanisms underlying its effect in human health.

Olive Paste-Enriched Cookies Exert Increased Antioxidant Activities

Functional foods are beneficial to human health and are part of the daily diet of people trying to follow a healthier lifestyle. Olive paste is a good source of functional compounds, mainly phenolic compounds, that have been shown to have health benefits. At the same time, cookies are an ideal snack that can be fortified with additional ingredients to address human dietary needs. The study aimed to enrich cookies with olive paste and extra ingredients for flavor differentiation and evaluate the impact of the enrichment on their antioxidant properties. Enriched cookies were prepared analyzed and tested for sensorial acceptability, total phenolics, and antioxidant activities by DPPH, ABTS, FRAP, and CUPRAC assays. Enriched cookies were sensorially acceptable. Unsaturated fat, total phenolics, and antioxidant activities of enriched cookies were higher compared to control cookies, while among enriched cookies the extra addition of 1% garlic, 0.5% thyme, and 0.5% oregano resulted in higher total phenolics and antioxidant activities compared to cookies that were flavored either with 3% vegetables or 3% orange zest. Antioxidant activity in cookies was strongly correlated with total phenolic content. Cookies enriched with olive paste may be healthy functional food in terms of increased antioxidant activity.

A comprehensive review on different classes of polyphenolic compounds present in edible oils

Edible oils are used as a frying medium and in the preparation of several food products. They are mainly constituting triacylglycerols as major components, while other compounds are classified as minor constituents, which include polyphenols. This class of compounds plays an important role in the thermal stability and quality attributes of the finished industrial food products. In addition to other antioxidants, the desired thermal stability of edible is achieved by either fortification or mixing of edible oils. This comprehensive review was therefore aimed to review the different classes of polyphenolic compounds present in commonly consumed edible oils. The edible oils reviewed include soybean, olive, rapeseed, canola, sunflower, flaxseed, sesame, cottonseed, palm, almond, peanut, chestnut, coconut, and hazelnut oils. The identified classes of polyphenolic compounds such as simple phenols, hydroxybenzoic acids, phenylethanoids, hydroxycinnamic acid, esters of hydroxycinnamic acids, coumarins & chromans, stilbenes, flavonoids, anthocyanins, and lignans were discussed. It was observed that a single edible from different origins showed the varied composition of the different classes of phenolic compounds. Among the oils, soybean, sunflower, olive, and brassica oils received higher attention in terms of polyphenol composition. Some classes of phenolic compounds were either not reported or absent in one edible oil, while present in others. Among the different classes of phenolics, hydroxybenzoic acids, hydroxycinnamic acid and flavonoids were the most widely present compounds. Phenolic compounds in edible oils possess several health benefits such as antioxidant, antibacterial, anti-viral, anti-inflammatory, anti-tumour, antioxidants, cardioprotective, neuroprotective, anti-diabetic properties and anti-obesity.

Green Synthesized Magnetic Nanoparticles as Effective Nanosupport for the Immobilization of Lipase: Application for the Synthesis of Lipophenols

In this work, hybrid zinc oxide-iron oxide (ZnOFe) magnetic nanoparticles were synthesized employing Olea europaea leaf aqueous extract as a reducing/chelating and capping medium. The resulting magnetic nanoparticles were characterized by basic spectroscopic and microscopic techniques, namely, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fourier-transform infrared (FTIR) and atomic force microscopy (AFM), exhibiting a spherical shape, average size of 15-17 nm, and a functionalized surface. Lipase from Thermomyces lanuginosus (TLL) was efficiently immobilized on the surface of ZnOFe nanoparticles through physical absorption. The activity of immobilized lipase was found to directly depend on the enzyme to support the mass ratio, and also demonstrated improved pH and temperature activity range compared to free lipase. Furthermore, the novel magnetic nanobiocatalyst (ZnOFe-TLL) was applied to the preparation of hydroxytyrosyl fatty acid esters, including derivatives with omega-3 fatty acids, in non-aqueous media. Conversion yields up to 90% were observed in non-polar solvents, including hydrophobic ionic liquids. Different factors affecting the biocatalyst performance were studied. ZnOFe-TLL was reutilized for eight subsequent cycles, exhibiting 90% remaining esterification activity (720 h of total operation at 50 °C). The green synthesized magnetic nanoparticles, reported here for the first time, are excellent candidates as nanosupports for the immobilization of enzymes with industrial interest, giving rise to nanobiocatalysts with elevated features.

Table olives and health: a review

Table olives, a product of olive tree (Olea europaea L.), is an important fermented product of the Mediterranean Diet. Agronomical factors, particularly the cultivar, the ripening stage and the processing method employed are the main factors influencing the nutritional and non-nutritional composition of table olives and their organoleptic properties. The important nutritional value of this product is due to its richness in monounsaturated fat (MUFA), mainly oleic acid, fibre and vitamin E together with the presence of several phytochemicals. Among these, hydroxytyrosol (HT) is the major phenolic compound present in all types of table olives. There is a scarcity of in vitro, in vivo and human studies of table olives. This review focused comprehensively on the nutrients and bioactive compound content as well as the health benefits assigned to table olives. The possible health benefits associated with their consumption are thought to be primarily related to effects of MUFA on cardiovascular health, the antioxidant (AO) capacity of vitamin E and its role in protecting the body from oxidative damage and the anti-inflammatory and AO activities of HT. The influence of multiple factors on composition of the end product and the potential innovation in the production of table olives through the reduction of its final salt content was also discussed.

Antique Traditional Practice: Phenolic Profile of Virgin Olive Oil Obtained from Fruits Stored in Seawater

Virgin olive oil (VOO) is a functional food specific to the Mediterranean diet and related to human health, especially as a protector of cardiovascular health, in the prevention of several types of cancers, and in modification of immune and inflammatory response. Phenolic compounds have central importance for these extraordinary health benefits. In the production of high-quality olive oils, it is very important to process freshly picked olives and avoid any storage of fruits. However, in Croatia there is a very traditional and environmentally friendly method of olive oil production, where olive fruits are stored in seawater for some time prior to processing. This practice is also notable nowadays since there are people who prefer the characteristic flavor of the “seawater olive oil”, although some people argue against its quality and biomedical relevance. In this study, the phenolic contents of VOO prepared from the immediately processed fresh olives and olives processed after storage in seawater were compared with the use of high-performance liquid chromatography-mass spectrometry (HPLC-MS) and spectrophotometric analysis. The results suggest that “seawater olive oil” should be considered as a safe food of biomedical relevance, as it still contains a significant proportion of important phenolics like hydroxytyrosol, tyrosol and oleacein (e.g., 63.2% of total phenols in comparison to VOO).

Emulsion gels as delivery systems for phenolic compounds: Nutritional, technological and structural properties

Polyphenols have interesting antioxidant properties and could help prevent certain diseases. Emulsion gels (EGs) have characteristics that make them a promising alternative system for supplying several bioactive compounds simultaneously, among them polyphenols. We produced four EGs containing olive oil, soy protein and a cold gelling agent based on alginate. One basic formulation (ES) contained only these ingredients and was used as a reference, while the other three also contained different solid polyphenol extracts from grape seed (G), grape seed and olive (O) or grape total (T), called ESG, ESO and EST, respectively. The corresponding EGs were prepared by mixing soy protein, alginate, water and one of these types of polyphenol extract (G, O or T), using a homogenizer. Then, the olive oil was gradually added to the mixture and finally, each mixture was placed in a metal container under pressure and chilled for 24 h until they formed an EG. The composition (including concentrations of phenolic metabolites), and technological and structural properties of these EGs were evaluated. Hydroxytyrosol was identified in all the EGs, but ESO showed the highest (P < 0.05) content. The EGs with added polyphenols showed contents of gallic acid, flavanol monomers and derivatives, with ESG showing the highest (P < 0.05) content. All the EGs showed optimal thermal stability, while colour and texture parameters were significantly influenced by the type of polyphenol extract added. No significant differences in the frequency or half-bandwidth of the 2923 and 2853 cm^-1 infrared bands were observed.