NMR Determination of Free Fatty Acids in Vegetable Oils

Analytical approaches for the determination of adulterated animal fats and vegetable oils in food and non-food samples

Edible oils and fats are crucial components of everyday cooking and the production of food products, but their purity has been a major issue for a long time. High-quality edible oils are contaminated with low- and cheap-quality edible oils to increase profits. The adulteration of edible oils and fats also produces many health risks. Detection of main and minor components can identify adulterations using various techniques, such as GC, HPLC, TLC, FTIR, NIR, NMR, direct mass spectrometry, PCR, E-Nose, and DSC. Each detection technique has its advantages and disadvantages. For example, chromatography offers high precision but requires extensive sample preparation, while spectroscopy is rapid and non-destructive but may lack resolution. Direct mass spectrometry is faster and simpler than chromatography-based MS, eliminating complex preparation steps. DNA-based oil authentication is effective but hindered by laborious extraction processes. E-Nose only distinguishes odours, and DSC directly studies lipid thermal properties without derivatization or solvents. Mass spectrometry-based techniques, particularly GC-MS is found to be highly effective for detecting adulteration of oils and fats in food and non-food samples. This review summarizes the benefits and drawbacks of these analytical approaches and their use in conjunction with chemometric tools to detect the adulteration of animal fats and vegetable oils. This combination provides a powerful technique with enormous chemotaxonomic potential that includes the detection of adulterations, quality assurance, assessment of geographical origin, assessment of the process, and classification of the product in complex matrices from food and non-food samples.

Comparison between Traditional and Novel NMR Methods for the Analysis of Sicilian Monovarietal Extra Virgin Olive Oils: Metabolic Profile Is Influenced by Micro-Pedoclimatic Zones

Nuclear magnetic resonance (NMR) metabolomic analysis was applied to investigate the differences within nineteen Sicilian Nocellara del Belice monovarietal extra virgin olive oils (EVOOs), grown in two zones that are different in altitude and soil composition. Several classes of endogenous olive oil metabolites were quantified through a nuclear magnetic resonance (NMR) three-experiment protocol coupled with a yet-developed data-processing called MARA-NMR (Multiple Assignment Recovered Analysis by Nuclear Magnetic Resonance). This method, taking around one-hour of experimental time per sample, faces the possible quantification of different class of compounds at different concentration ranges, which would require at least three alternative traditional methods. NMR results were compared with the data of traditional analytical methods to quantify free fatty acidity (FFA), fatty acid methyl esters (FAMEs), and total phenol content. The presented NMR methodology is compared with traditional analytical practices, and its consistency is also tested through slightly different data treatment. Despite the rich literature about the NMR of EVOOs, the paper points out that there are still several advances potentially improving this general analysis and overcoming the other cumbersome and multi-device analytical strategies. Monovarietal EVOO's composition is mainly affected by pedoclimatic conditions, in turn relying upon the nutritional properties, quality, and authenticity. Data collection, analysis, and statistical processing are discussed, touching on the important issues related to the climate changes in Sicily and to the specific influence of pedoclimatic conditions.

Cutin-derived oligomers induce hallmark plant immune responses

The cuticle constitutes the outermost defensive barrier of most land plants. It comprises a polymeric matrix-cutin, surrounded by soluble waxes. Moreover, the cuticle constitutes the first line of defense against pathogen invasion, while also protecting the plant from many abiotic stresses. Aliphatic monomers in cutin have been suggested to act as immune elicitors in plants. This study analyses the potential of cutin oligomers to activate rapid signaling outputs reminiscent of pattern-triggered immunity in the model plant Arabidopsis. Cutin oligomeric mixtures led to Ca2+ influx and mitogen-activated protein kinase activation. Comparable responses were measured for cutin, which was also able to induce a reactive oxygen species burst. Furthermore, cutin oligomer treatment resulted in a unique transcriptional reprogramming profile, having many archetypal features of pattern-triggered immunity. Targeted spectroscopic and spectrometric analyses of the cutin oligomers suggest that the elicitor compounds consist mostly of two up to three 10,16-dihydroxyhexadecanoic acid monomers linked together through ester bonds. This study demonstrates that cutin breakdown products can act as inducers of early plant immune responses. Further investigation is needed to understand how cutin breakdowns are perceived and to explore their potential use in agriculture.

A Comprehensive Study for Determination of Free Fatty Acids in Selected Biological Materials: A Review

The quality of oil is highly dependent on its free fatty acid (FFA) content, especially due to increased restrictions on renewable fuels. As a result, there has been a growing interest in free fatty acid determination methods over the last few decades. While various standard methods are currently available, such as the American Oil Chemists Society (AOCS), International Union of Pure and Applied Chemistry (IUPAC), and Japan Oil Chemists' Society (JOCS), to obtain accurate results, there is a pressing need to investigate a fast, accurate, feasible, and eco-friendly methodology for determining FFA in biological materials. This is owing to inadequate characteristics of the methods, such as solvent consumption and reproducibility, among others. This study aims to investigate FFA determination methods to identify suitable approaches and introduce a fresh perspective.

Multilayer microparticles for programmed sequential release of phenolic compounds from Eugenia stipitata: Stability and bioavailability

A co-delivery system based on multilayer microparticles was developed and characterized for the sequential release of phenolic compounds (PCs) using different encapsulation processes (spray drying: SD and drying-chilling spray: SDC) and wall materials to improve the stability and bioavailability of PCs. Samples were characterized in terms of process yield (PY%), phenolic retention efficiency (PRE%), chemical structure and crystallinity (NMR, FTIR, DXR), thermal stability (DSC and FT-IR), anti-radical capacity (ORAC and ABTS) and in vitro digestion. PRE% of samples by SD were higher (p < 0.05) than SDC due to the formation of PCs from CRF (cará-roxo flour). NMR, FTIR, DXR confirmed the presence of key components and interactions for the formation of the advanced co-delivery system. The SDC particles showed crystalline regions by XRD and were stable at ∼47 °C. All samples showed good release of PC in the intestinal phase, and antiradical capacity that reached 23.66 µmol TE g-1.

Fatty Acids and Starch Identification within Minute Archaeological Fragments: Qualitative Investigation for Assessing Feasibility

Within the realm of archaeology, the analysis of biomolecules assumes significant importance in elucidating historical dietary patterns and their implications for contemporary contexts. To achieve this, knowledge and tools of both chemistry and archaeology are essential to yield objective outcomes and conduct analyses of archaeological materials for the detection of biomolecules. Usually, only minuscule remnants of ceramic fragments are retrieved from excavations, which limits the feasibility of comprehensive laboratory analysis. This study aimed to establish a protocol for analyzing fatty acids and starch from archaeological food utensils with minimal sample quantities. Various experiments were conducted to replicate preparations that might have occurred in archaeological vessels, aiming to establish the optimal protocol. The analyses were performed using clay griddles, subjecting vegetable oil to varying temperatures for fatty acid assessment. For starch analysis, a series of experiments encompassed diverse forms of potato preparations (pulp, chuño, tortilla, carbonization, and freeze-drying) and maize (flour, tortilla, and carbonization). The verification of the experiments was confirmed by conducting identical analyses, as developed in the current study, on authentic archaeological fragments. The principal outcomes of this investigation include the successful extraction of both types of biomolecules using only 0.25 g of the sample, obtained through direct scraping from the vessel. Soxhlet extraction was identified as the most efficient strategy to recover fatty acids. Additionally, a comprehensive protocol for the identification of starch extraction was developed. This study has, for the first time, elucidated two detailed methodologies for the extraction of fatty acids and starch in scenarios in which researchers can obtain limited quantities of archaeological food utensil fragments.

Effects of Ajwa date seeds on the oxidative stability of butter

Butter is a widely used food product. However, owing to its rich fatty acid content (saturated and unsaturated fatty acids), it is prone to lipid oxidation, which may affect the quality of butter-containing products. Because of the possible toxic properties of synthetic antioxidants, recent research has focused on the use of natural antioxidants. This study aimed to evaluate the effects of Ajwa date seeds as natural antioxidants to retard lipid oxidation in butter. Date seeds as either a powder or extract were added to butter at concentrations of 0.5 % and 1 %; 100 % butter was used as the control. The samples were stored at 60 °C for 21 d. Radical scavenging activity, peroxide value, acid value, and thiobarbituric acid value (TBA) were analysed every 7 d. This study revealed a strong relationship between storage period and oxidative stability parameters. After 21 d, butter containing date seed powder exhibited higher radical scavenging activity than date seed extract. A reduction in peroxide, acid, and TBA values was also observed in butter samples containing date seed powder. In conclusion, date seed powder increased the oxidative stability of butter. Therefore, adding date seed powder to butter-rich food products can increase their shelf-life and stability.

Multivariate modelling analysis for prediction of glycidyl esters and 3-monochloropropane-1,2-diol (3-MCPD) formation in periodically heated palm oil

Palm oil is a vegetable oil that is widely used for cooking and deep-frying because of its affordability. However, repeatedly heated palm oil is also prone to oxidation due to its significant content of unsaturated fatty acids and other chemical toxicants such as glycidyl esters and 3-monochloropropane-1,2-diol (3-MCPD). Initially, the physicochemical properties such as colour, viscosity, peroxide, p-anisidine and total oxidation (TOTOX) of periodically heated palm oil were investigated. Chemical profiling and fingerprinting of six different brands of palm cooking oil during heating cycles between 90 and 360 min were conducted using Fourier transform infrared (FTIR) and 1H Nuclear Magnetic Resonance (NMR) metabolomics. In addition, the multivariate analysis was employed to evaluate the 1H NMR spectroscopic pattern of repeatedly heated palm oil with the corresponding physicochemical properties. The FTIR metabolomics showed significant different of the chemical fingerprinting subjected to heating duration, which in agreement with the result of 1H NMR metabolomics. Partial least squares (PLS) model revealed that most of the physicochemical properties of periodically heated palm oil are positively correlated (R2 values of 0.98-0.99) to their spectroscopic pattern. Based on the findings, the color of the oils darkened with increased heating time. The peroxide value (PV), p-anisidine value (p-AnV), and total oxidation (TOTOX) values increased significantly due to degradation of unsaturated compounds and oxidation products formed. We identified targeted metabolites (probable carcinogens) such as 3-monochloropropane-1,2-diol (3-MCPD) and glycidyl ester (GE), indicating the conversion of 3-MCPD to GE in repeatedly heated oils based on PCA and OPLSDA models. Our correlation analysis of NMR and physicochemical properties has shown that the conversion of 3-MCPD to GE was significantly increased from 180 to 360 min cooking time. The combination spectroscopic techniques with physicochemical properties are a reliable and robust methods to evaluate the characteristics, stability and chemical's structure changes of periodically heated palm oil, which may contribute to probable carcinogens development. This study has proven that combination of NMR and physicochemical analysis may predict the formation of the probable carcinogens of heated cooking oil over time which emphasizing the need to avoid certain heating cycles to mitigate formation of probable carcinogens during cooking process.

Evening primrose oil: a comprehensive review of its bioactives, extraction, analysis, oil quality, therapeutic merits, and safety

Oil crops have become increasingly farmed worldwide because of their numerous functions in foods and health. In particular, oil derived from the seeds of evening primrose (Oenothera biennis) (EPO) comprises essential fatty acids of the omega-6 (ω-6) series. It is well recognized to promote immune cells with a healthy balance and management of female ailments. The nutrients of interest in this oil are linoleic acid (LA, 70-74%) and γ-linolenic acid (GLA, 8-10%), which are polyunsaturated fatty acids (PUFA) that account for EPO's popularity as a dietary supplement. Various other chemicals in EPO function together to supply the body with PUFA, elevate normal ω-6 essential fatty acid levels, and support general health and well-being. The inclusive EPO biochemical analysis further succeeded in identifying several other components, i.e., triterpenes, phenolic acids, tocopherols, and phytosterols of potential health benefits. This comprehensive review capitalizes on EPO, the superior product of O. biennis, highlighting the interrelationship between various methods of cultivation, extraction, holistic chemical composition, sensory characters, and medicinal value. Besides the literature review, this study restates the numerous health advantages of primrose oil and possible drug-EPO interactions since a wide spectrum of drugs are administered concomitantly with EPO. Modern techniques to evaluate EPO chemical composition are addressed with emphasis on the missing gaps and future perspectives to ensure best oil quality and nutraceutical benefits.

Evaluation of bioactive compounds from Ficus carica L. leaf extracts via high-performance thin-layer chromatography combined with effect-directed analysis

This study compares different solvent systems with the use of spontaneous fermentation on the phytochemical composition of leaf extracts from a locally grown white variety of common fig (Ficus carica Linn.). The aim was to detect and identify bioactive compounds that are responsible for acetylcholinesterase (AChE), α-amylase and cyclooxygenase-1 (COX-1) enzyme inhibition, and compounds that exhibit antimicrobial activity. Bioactive zones in chromatograms were detected by combining High-performance thin-layer chromatography (HPTLC) with enzymatic and biological assays. A new experimental protocol for measuring the relative half-maximum inhibitory concentration (IC50) was designed to evaluate the potency of the extracts compared to the potency of known inhibitors. Although the IC50 of the fig leaf extract for α-amylase and AChE inhibition were significantly higher when compared to IC50 for acarbose and donepezil, the COX-1 inhibition by the extract (IC50 = 627 µg) was comparable to that of salicylic acid (IC50 = 557 µg), and antimicrobial activity of the extract (IC50 = 375-511 µg) was similar to ampicillin (IC50 = 495 µg). Four chromatographic zones exhibited bioactivity. Compounds from detected bioactive bands were provisionally identified by comparing the band positions to coeluted standards, and by Fourier transform infrared (FTIR) spectra from eluted zones. Flash chromatography was used to separate selected extract into fractions and isolate fractions that are rich in bioactive compounds for further characterisation with nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography-mass spectrometry (LC-MS) analysis. The main constituents identified were umbelliferon (zone 1), furocoumarins psoralen and bergapten (zone 2), different fatty acids (zone 3 and 4), and pentacyclic triterpenoids (calotropenyl acetate or lupeol) and stigmasterol (zone 4).

Preparing epoxidized vegetable oil from waste generated by the kapok fiber industry and assessing its thermal stabilization effect as a co-stabilizer for polyvinyl chloride

This paper describes the epoxidation of vegetable oil derived from waste kapok seeds using performic acid, which was generated in situ with sulfuric acid acting as a catalyst. The mole ratio of formic acid to double bonds varied between 0.25 and 1.00. The completion of the reaction has been verified by analyzing FTIR and NMR spectra. The resulting epoxidized kapok seed oil (EKSO) has a maximum oxirane oxygen content of 2.7%, achieved at a formic acid to double bond mole ratio of 0.5. The study has also examined the potential use of EKSO as a co-stabilizer in the presence of Ca/Zn stearate for stabilizing polyvinyl chloride (PVC). Both static and dynamic tests demonstrated that incorporating EKSO into the Ca/Zn stearate system leads to a significant increase in the thermal stability of PVC. Moreover, the effectiveness of EKSO as a co-stabilizer was found to be comparable to that of epoxidized soybean oil (ESBO). However, the use of EKSO did result in a decrease in the strength of PVC due to an increase in plasticity, although this effect was minimal at low dosages and was also observed with ESBO. On the other hand, when utilizing small doses (<2 phr), there is a tendency for flowability to decrease, but the reduction is not significant either. Overall, these findings suggest that EKSO could be a valuable co-stabilizer for PVC in industrial applications, as it enhances PVC's thermal stability without significantly compromising its mechanical and flow properties.

Simultaneous mitigation of 3-monochloropropane 1,2 diol ester and glycidyl ester in edible oils: a review

The rising concern about the presence of 3-monochloropropane 1,2 diol ester (3-MCPDE) and glycidyl ester (GE) in food has prompted much research to be conducted. Some process modifications and the use of specific chemicals have been employed to mitigate both 3-MCPDE and GE. Alkalisation using NaOH, KOH, alkali metals or alkaline earth metals and post sparging with steam or ethanol and short path distillation have shown simultaneous mitigation of 51-91% in 3-MCPDE and of 13-99% in GE, both contaminants achieved below 1000 µg/kg. Some of the mitigation methods have resulted in undesirable deterioration in other parameters of the refined oil. When the processed oil is used in food processing, it results in changes to 3-MCPDE and GE. Repeated deep frying above 170 °C in the presence of NaCl and baking at 200 °C with flavouring (dried garlic and onion), resulted in increased 3-MCPDE. Repeated frying in the presence of antioxidants (TBHQ, rosemary and phenolics) decreased 3-MCPDE in processed food. The GE content in foods tends to decline with time, indicating instability of GE's epoxide ring.

Property Improvements of Silica-Filled Styrene Butadiene Rubber/Butadiene Rubber Blend Incorporated with Fatty-Acid-Containing Palm Oil

Using vegetable oils as a plasticizer or processing aid in green rubber products is becoming popular due to environmental concerns. However, differences in vegetable oil processing result in varying amounts of low-molecular-weight (low-MW) free fatty acids (FFAs) in their composition, which range from 2% to 30%. This research investigated how the properties of silica-filled styrene butadiene rubber (SBR) and butadiene rubber (BR) blends were affected by the presence of FFAs in palm oil (PO). The rubber compounds containing a 70/30 SBR/BR blend, 30 phr of silica, and 2 phr of bis-(3-triethoxysilylpropyl) tetrasulfide (TESPT), and the vulcanizing agents were prepared and tested. The PO content was kept constant at 20 phr, while the number of FFAs, i.e., lauric acid (LA), palmitic acid (PA), and oleic acid (OA), in PO varied from 10-30%. The viscosity, dynamic mechanical properties, morphology, cure characteristics, and mechanical properties of the rubber blend were then measured. Regardless of the FFA types, increasing FFA content in PO decreased scorch time, cure time, minimum torque, and viscosity. As the FFA content increased, the torque difference and crosslink density also increased, which led to higher hardness, modulus, tensile strength, and abrasion resistance. The FFA types had a slight effect on the vulcanizate properties, even though LA showed slightly better mechanical properties than PA and OA. The results reveal that FFAs in PO not only improve processability but also function as a co-activator in silica-filled sulfur-vulcanized SBR/BR blend compounds.

Ultrastructural, Energy-Dispersive X-ray Spectroscopy, Chemical Study and LC-DAD-QToF Chemical Characterization of Cetraria islandica (L.) Ach

The lichen Cetraria islandica (L.) Ach. has been used in traditional and modern medicines for its many biological properties such as immunological, immunomodulating, antioxidant, antimicrobial, and anti-inflammatory activities. This species is gaining popularity in the market, with interest from many industries for selling as medicines, dietary supplements, and daily herbal drinks. This study profiled the morpho-anatomical features by light, fluorescence, and scanning electron microscopy; conducted an elemental analysis using energy-dispersive X-ray spectroscopy; and phytochemical analysis was performed using high-resolution mass spectrometry combined with a liquid chromatography system (LC-DAD-QToF) of C. islandica. In total, 37 compounds were identified and characterized based on comparisons with the literature data, retention times, and their mass fragmentation mechanism/s. The identified compounds were classified under five different classes, i.e., depsidones, depsides, dibenzofurans, aliphatic acids, and others that contain simple organic acids in majority. Two major compounds (fumaroprotocetraric acid and cetraric acid) were identified in the aqueous ethanolic and ethanolic extracts of C. islandica lichen. This detailed morpho-anatomical, EDS spectroscopy, and the developed LC-DAD-QToF approach for C. islandica will be important for correct species identification and can serve as a useful tool for taxonomical validation and chemical characterization. Additionally, chemical study of the extract of C. islandica led to isolation and structural elucidation of nine compounds, namely cetraric acid (1), 9'-(O-methyl)protocetraric acid (2), usnic acid (3), ergosterol peroxide (4), oleic acid (5), palmitic acid (6), stearic acid (7), sucrose (8), and arabinitol (9).

Lipidomics in food quality and authentication: A comprehensive review of novel trends and applications using chromatographic and spectroscopic techniques

Lipid analysis is an integral part of food authentication and quality control which provides consumers with the necessary information to make an informed decision about their lipid intake. Recent advancement in lipid analysis and lipidome scope represents great opportunities for food science. In this review we provide a comprehensive overview of available tools for extraction, analysis and interpretation of data related to dietary fats analyses. Different analytical platforms are discussed including GC, MS, NMR, IR and UV with emphasis on their merits and limitations alongside complementary tools such as chemometric models and lipid-targeted online databases. Applications presented here include quality control, authentication of organic and delicacy food, tracing dietary fat source and investigating the effect of heat/storage on lipids. A multitude of analytical methods with different sensitivity, affordability, reproducibility and ease of operation are now available to comprehensively analyze dietary fats. Application of these methods range from studies which favor the use of large data generating platforms such as MS-based methods, to routine quality control which demands easy to use affordable equipment as TLC and IR. Hence, this review provides a navigation tool for food scientists to help develop an optimal protocol for their future lipid analysis quest.

Correlation of tangible quality parameters of vegetable-based transformer fluids

Due to the inherent environmental footprint of petroleum derived transformer fluids, the power industry is gradually exploring the potential of vegetable oils as alternatives. The impetus comes mostly from vegetable oils renewability and their inherent biodegradability. However, the major drawback in the use of vegetable oils as dielectric fluids is their lower oxidative stability and higher kinematic viscosity compared to mineral oils. The results obtained clearly demonstrate the correlation between spectroscopic data induction time, kinematic viscosity, acid value, and peroxide value. Quantitatively, the absorption frequencies of functional groups in vegetable oil transformer fluids that can be correlated to the mentioned quality parameters show noticeable changes with aging/oxidative degradation. The study also demonstrates the utility of integrating spectroscopic data to understand trends in induction time and kinematic viscosity of oil samples heated under transformer service conditions.

Cytotoxic and Antimigratory Activity of Retrochalcones from Glycyrrhiza echinata L. on Human Cancer Cells

Cytotoxic activity-guided fractionation studies on Glycyrrhiza echinata roots led to the isolation of eight compounds (1-8). Chemical structures of the isolates were identified by NMR and MS analysis. Among the tested molecules, retrochalcones namely echinatin (3) (IC₅₀ =23.45-41.83 μM), licochalcone B (4) (IC₅₀ =36.04-39.53 μM) and tetrahydroxylmethoxychalcone (5) (IC₅₀ =7.09-80.81 μM) were the most active ones against PC3, MCF7 and HepG2 cells. Moreover, 5 exhibited selectivity on prostate cancer cells (SI: 5.19). Hoechst staining and Annexin V/PI binding assays as well as cell cycle analysis on the compounds 3 (23 μM) and 5 (5 and 7 μM) demonstrated that these retrochalcones induced apoptosis and significantly suppressed cell cycle in G₁ and G₂ /M phases. Furthermore, 3 and 5 showed antimigratory effects on PC3 cells by wound healing assay. The results indicated that tested retrochalcones most particularly 5 could be potential anticancer drug candidates that prevent proliferation and migration of cancer cells.

Conversion of Free Fatty Acid in Calophyllum inophyllum Oil to Fatty Acid Ester as Precursor of Bio-Based Epoxy Plasticizer via SnCl2-Catalyzed Esterification

The preparation and application of bio based plasticizers derived from vegetable oils has gained increasing attention in the polymer industry to date due to the emerging risk shown by the traditional petroleum-based phthalate plasticizer. Epoxy fatty acid ester is among the prospective alternative plasticizers since it is ecofriendly, non-toxic, biodegradable, low migration, and low carbon footprint. Epoxy plasticizer can be synthesized by the epoxidation reaction of fatty acid ester. In this study, the preparation of fatty acid ester as a green precursor of epoxy ester plasticizer was performed via esterification of free fatty acid (FFA) in high acidic Calophyllum inophyllum Seed Oil (CSO) using methanol in the presence of SnCl₂.2H₂O catalyst. The analysis of the process variables and responses using Box-Behnken Design (BBD) of Response Surface Methodology (RSM) was also accomplished. It was found that the quadratic model is the most appropriate model for the optimization process. The BBD analysis demonstrated that the optimum FFA conversion and residual FFA content were 75.03% and 4.59%, respectively, achieved at the following process condition: a reaction temperature of 59.36 °C, a reaction time of 117.80 min, and a catalyst concentration of 5.61%. The fatty acid ester generated was an intermediate product which can undergo a further epoxidation process to produce epoxy plasticizer in polymeric material production.

Phytochemical, Antimicrobial, Antioxidant, and In Vitro Cytotoxicity Evaluation of Echinops erinaceus Kit Tan

Wild plants are used by many cultures for the treatment of diverse ailments. However, they are formed from mixtures of many wanted and unwanted phytochemicals. Thus, there is a necessity to separate the bioactive compounds responsible for their biological activity. In this study, the chemical composition as well as antimicrobial and cytotoxic activities of Echinops erinaceus Kit Tan (Asteraceae) were investigated. This led to the isolation and identification of seven compounds, two of which are new (erinaceosin C3 and erinaceol C5), in addition to methyl oleate (C1) and ethyl oleate (C2), loliolide (C4), (E)-p-coumaric acid (C6), and 5,7,3`,5`-tetrahydroxy flavanone (C7). The structures of the isolated compounds were elucidated by 1D, 2D NMR, and HR-ESI-MS. The methanol extract showed the highest antimicrobial activity among the tested extracts and fractions. The n-hexane and EtOAc extracts showed remarkable antimicrobial activity against B. subtilus, P. aeruginosa, E. coli, and C. albicans. A cytotoxicity-guided fractionation of the most bioactive chloroform extract resulted in the isolation of bioactive compounds C1/C2, which showed significant cytotoxicity against HCT-116 and CACO2 cell lines (IC50 24.95 and 19.74 µg/mL, respectively), followed by compounds C3 (IC50 82.82 and 76.70 µg/mL) and C5 (IC50 99.09 and 87.27 µg/mL), respectively. The antioxidant activity of the bioactive chloroform fractions was screened. Molecular docking was used to explain the results of the antimicrobial and anticancer activities against five protein targets, including DNA gyrase topoisomerase II, enoyl-acyl carrier protein reductase of S. aureus (FabI), dihydrofolate reductase (DHFR), β-catenin, and human P-glycoprotein (P-gp).

Determination of Maximum Oil Yield, Quality Indicators and Absorbance Spectra of Hulled Sunflower Seeds Oil Extraction under Axial Loading

The present study aims to estimate the maximum oil yield of hulled sunflower seed samples in a uniaxial process under a load of 40 kN and speed of 4 mm/min. The oil samples were assessed for their quality parameters and spectra curves within the wavelength range of 325–600 nm. The results show that heating temperatures in the range of 40 °C to 80 °C increased the oil output; however, a maximum oil yield of 48.869 ± 6.023% with a minimum energy of 533.709 ± 65.644 J at the fifth repeated pressing was obtained from the unheated sample compared to the heated samples. The peroxide values ranged from 6.898 ± 0.144 to 7.290 ± 0.507 meq O₂/kg, acid values from 1.043 ± 0.166 to 1.998 ± 0.276 mg KOH/g oil and free fatty acid values from 0.521 ± 0.083 to 0.999 ± 0.138 mg KOH/g oil, which were within the recommended quality threshold. There were significant spectral differences among the oil samples. A single absorbance peak was observed at 350 nm for all oil samples, indicating low levels of pigment molecules in the oil. The study revealed the need for repeated pressings to recover the considerable residual oil remaining in the seedcake after the first pressing.

In vitro and in silico studies of SARS-CoV-2 main protease Mpro inhibitors isolated from Helichrysum bracteatum

Discovering SARS-CoV-2 inhibitors from natural sources is still a target that has captured the interest of many researchers. In this study, the compounds (1-18) present in the methanolic extract of Helichrysum bracteatum were isolated, identified, and their in vitro inhibitory activities against SARS-CoV-2 main protease (Mpro) was evaluated using fluorescence resonance energy transfer assay (FRET-based assay). Based on 1D and 2D spectroscopic techniques, compounds (1-18) were identified as 24-β-ethyl-cholesta-5(6),22(23),25(26)-triene-3-ol (1), α-amyrin (2), linoleic acid (3), 24-β-ethyl-cholesta-5(6),22(23),25(26)-triene-3-O-β-d-glucoside (4), 1,3-propanediol-2-amino-1-(3',4'-methylenedioxyphenyl) (5), (-)-(7R,8R,8'R)-acuminatolide (6), (+)-piperitol (7), 5,7,4'-trihydroxy-8,3'-dimethoxy flavanone (8), 5,7,4'-trihydroxy-6-methoxy flavanone (9), 4',5-dihydroxy-3',7,8-trimethoxyflavone (10), 5,7-dihydroxy-3',4',5',8-tetramethoxy flavone (11), 1,3-propanediol-2-amino-1-(4'-hydroxy-3'-methoxyphenyl) (12), 3',5',5,7-tetrahydroxy-6-methoxyflavanone (13), simplexoside (piperitol-O-β-d-glucoside) (14), pinoresinol monomethyl ether-β-d-glucoside (15), orientin (16), luteolin-3'-O-β-d-glucoside (17), and 3,5-dicaffeoylquinic acid (18). Compounds 6, 12, and 14 showed comparable inhibitory activities against SARS-CoV-2 Mpro with IC50 values of 0.917 ± 0.05, 0.476 ± 0.02, and 0.610 ± 0.03 μM, respectively, compared with the control lopinavir with an IC50 value of 0.225 ± 0.01 μM. The other tested compounds showed considerable inhibitory activities. The molecular docking study for the tested compounds was carried out to correlate their binding modes and affinities for the SARS-CoV-2 Mpro enzyme with the in vitro results. Analyzing the results of the in vitro assay together with the obtained in silico results led to the conclusion that phenylpropanoids, lignans, and flavonoids could be considered suitable drug leads for developing anti-COVID-19 therapeutics. Moreover, the phenylpropanoid skeleton oxygenated at C3, C4 of the phenyl moiety and at C1, C3 of the propane parts constitute an essential core of the SARS-CoV-2 Mpro inhibitors, and thus could be proposed as a scaffold for the design of new anti-COVID-19 drugs.

Unfilled Natural Rubber Compounds Containing Bio-Oil Cured with Different Curing Systems: A Comparative Study

This study focuses on the properties of unfilled natural rubber compounds containing bio-oils cured with a peroxide curing system and then discusses the comparisons to those cured using the sulfur system from our previous work. Two types of bio-oils, i.e., palm oil and soybean oil, were used, and distillate aromatic extract (DAE)-based petroleum oil was employed as a reference. The bio-oils caused no significant change in the vulcanization of rubber compounds cured using peroxide. However, the compounds containing bio-oils and cured with sulfur showed a faster vulcanization than the ones with DAE. The bio-oils strongly affected the crosslink density of rubber compounds in both curing systems. The use of bio-oils caused a low crosslink density due to the possible implication of curing agents to bio-oil molecules. The properties of rubber compounds dependent on the different levels of crosslink density were also investigated. The results revealed that when the crosslink density increased, the modulus, tensile strength, and hardness of the rubber compounds increased and the elongation at break and compression set decreased. The use of bio-oils in the rubber compounds cured with different curing systems gave low modulus at 300% strain, tensile strength, and hardness but high elongation at break and compression set when compared to the ones with DAE. However, no significant change was observed for the compression set of the rubber compounds cured using sulfur. With the presence of bio-oils, the properties of rubber compounds cured with sulfur system deteriorated less than those of the ones cured with peroxide.

Isolation of New Constituents from Whole Plant of Salsola imbricata Forssk. of Saudi Origin

This work describes the first report of the known glycosidic constituents β-sitosterol-3-O-β-d-glucoside-6'-palmitate (1), β-sitosterol-3-O-β-d-glucoside (2), momor-cerebroside I (3), phytolacca cerebroside (4), 1,2-di-O-palmitoyl-3-O-(6-sulfoquinovopyranosyl)-glycerol (5), isorhamnetin-3-robinobioside (6), and isorhamnetin-3-rutinoside (7) from the plant Salsola imbricata Forssk. grown in the eastern region of Saudi Arabia. The structures of the isolated compounds were elucidated from extensive 1D and 2D nuclear magnetic resonance (NMR), gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and chemical analyses. Compound 1 is reported for the first time from the Amaranthaceae family. In addition to the isolated and identified fatty alcohols, compounds 3, 4, 5, and 6 are also reported for the first time from the genus Salsola. The findings of this study suggest a contribution of the isolated compounds to the various biological activities reported for this plant.

Macrophage-targeted mannose-decorated PLGA-vegetable oil hybrid nanoparticles loaded with anti-inflammatory agents

This work pledge to extend the therapeutic windows of hybrid nanoparticulate systems by engineering mannose-decorated hybrid nanoparticles based on poly lactic-co-glycolic acid (PLGA) and vegetable oil for efficient delivery of two lipophilic anti-inflammatory therapeutics (Celecoxib-CL and Indomethacin-IMC) to macrophages. The mannose surface modification of nanoparticles is achieved via O-palmitoyl-mannose spacer during the emulsification and nanoparticles assembly process. The impact of targeting motif on the hydrodynamic features (R_H, PdI), stability (ζ-potential), drug encapsulation efficiency (DEE) is thoroughly investigated. Besides, the in vitro biocompatibility (MTT, LDH) and susceptibility of mannose-decorated formulations to macrophage as well their immunomodulatory activity (ELISA) are also evaluated. The monomodal distributed mannose-decorated nanoparticles are in the range of nanometric size (R_H < 115 nm) with PdI < 0.20 and good encapsulation efficiency (DEE = 46.15% for CL and 76.20% for IMC). The quantitative investigation of macrophage uptake shows a 2-fold increase in fluorescence (RFU) of cells treated with mannose-decorated formulations as compared to non-decorated ones (p < 0.001) suggesting an enhanced cell uptake respectively improved macrophage targeting while the results of ELISA experiments suggest the potential immunomodulatory properties of the designed mannose-decorated hybrid formulations.

Aquivion perfluorosulfonic superacid as an effective catalyst for selective epoxidation of vegetable oils

The acid-promoted epoxidation of vegetable oils was studied using a variety of acidic ion exchange resins as heterogeneous acid catalysts. Quantitative and selective epoxidation of a series of vegetable oils with different composition of saturated, mono-, di- and tri-unsaturated fatty acids was obtained upon identification of the more efficient catalyst and experimental conditions. Furthermore, optimized reaction conditions were successfully applied to the epoxidation of a waste cooking oil, thus extending our procedure to the valorization of a biowaste, an area of increasing importance within a more sustainable society. The use of quantitative ¹HNMR besides making accurate evaluation of the amounts of reagents to be employed and of the selectivity, allowed facile and rapid quantification of mono-, di- and tri-epoxides, thus providing an indirect indication on the fatty acid composition of the vegetable oils, even in the presence of very low quantities of linolenic acid.

Melanin Pathway Determination in Sclerotium cepivorum Berk Using Spectrophotometric Assays, Inhibition Compound, and Protein Validation

Sclerotium cepivorum Berk is the etiological agent of white rot disease that affects plants of the genus Allium. This fungus produces resistance structures called sclerotia that are formed by a rolled mycelium with a thick layer of melanin and it can remain dormant for many years in the soil. Current interest in S. cepivorum has arisen from economic losses in Allium crops in the agricultural sector. Melanin is a component that protects the sclerotia from adverse environmental conditions In many organisms, it plays an important role in the infectious process; in S. cepivorum, the pathway by which this component is synthetized is not fully described. By using infrared spectrophotometric assays applied direct to the sclerotia and a melanin extract followed by an NMR analysis and a tricyclazole melanin inhibition experiment, it allowed us to determine the dihydroxynaphthalene (DHN)-melanin pathway by which S. cepivorum performs its melanin synthesis. Moreover, we focused on studying scytalone dehydratase (SDH) as a key enzyme of the DHN-melanin synthesis. We obtained the recombinant SDH enzyme and tested its activity by a zymogram assay. Thereby, the S. cepivorum melanogenic route was established as a DHN pathway.

Flavanone Glycosides, Triterpenes, Volatile Compounds and Antimicrobial Activity of Miconia minutiflora (Bonpl.) DC. (Melastomataceae)

Chemical composition of the essential oils and extracts and the antimicrobial activity of Miconia minutiflora were investigated. The flavanone glycosides, pinocembroside and pinocembrin-7-O-[4″,6″-HHDP]-β-D-glucose, were identified, along with other compounds that belong mainly to the triterpene class, besides the phenolics, gallic acid and methyl gallate. Sesquiterpenes and monoterpenes were the major compounds identified from the essential oils. Screening for antimicrobial activity from the methanolic extract of the leaves showed that the MIC and MMC values against the tested microorganisms ranged from 0.625 to 5 mg·mL−1 and that the extract was active against microorganisms, Staphyloccocus aureus, Escherichia coli, and Bacillus cereus.

Fumarate Based Metal–Organic Framework: An Effective Catalyst for the Transesterification of Used Vegetable Oil

Advancement of technology for the sustainable production of biodiesel is of significant importance in fighting against rising fuel costs due to the fast depletion of fossil fuels. In this regard, the application of highly efficient MOFs (metal–organic frameworks)-based materials as acidic, basic, or supported heterogeneous catalysts plays a crucial role in enhancing the efficiency of biodiesel production processes. In this report, we demonstrate the synthesis and catalytic application of Zr-fumarate-MOF (also known as MOF-801) as a heterogeneous catalyst for the transesterification reaction of used vegetable oil (UVO) for the production of biodiesel. The formation of MOF-801 and its structural stability is confirmed by a variety of characterization techniques including XRD, SEM, EDX, FT-IR, BET, and TGA analyses. The results revealed the formations of highly crystalline, cubic MOF-801 possessing thermal stability below 500 °C. The MOF-801 catalyst demonstrated moderate catalytic activity during transesterification of UVO (~60%) at 50 wt.% of methanol: oil, 10 wt.% catalyst loading, 180 °C reaction temperature, and 8 h of reaction time. Furthermore, the catalyst has exhibited adequate reusability with a slight reduction in the reaction yield of up to ~10% after three cycles.

A new antiprotozoal compound from Calendula officinalis

A new phytoconstituent; (6Z,9Z)-heptadeca-6,9-diene-5,11-dione (1) was isolated from Calendula officinalis methanol extract. The structure of 1 was determined based on the analysis of NMR spectra and HRESIMS. It was tested for antimicrobial and antiprotozoal activities. Compound 1 showed leishmanicidal activity against L. donovani amastigote with an IC₅₀ of 16.4394 µM and IC₉₀ of 28.9015 µM and a weak antitrypanosomal activity with an IC₅₀ of 37.6136 µM. The cytotoxicity of 1 was evaluated using standard experimental procedures against THP1 cells and no cytotoxicity was observed indicating its selectivity and safety.Supplemental data for this article can be accessed here.

Streptomyces sp. 1S1 isolated from Southern coast of the Red Sea as a renewable natural resource of several bioactive compounds

Red Sea represents one of the most remarkable marine ecosystems. However, it is also one of the world's least explored areas of marine biodiversity. The aims of this investigation were therefore, to isolate marine microorganisms from the seashore sediments and water in shallow region from west Yemen coast, to assess their antimicrobial potential, to identify the highly active isolate, and to purify and identify the bioactive compounds from it. In this regard, twenty-five bacterial strains have been isolated from twenty samples and tested for their antimicrobial ability against some pathogenic bacteria and yeast by using the agar disk diffusion and agar well diffusion assay. Out of the total 25 marine actinomycetes isolates only 13 exhibited interesting antimicrobial activity. The morphological, biochemical, and phylogenetic characteristics of the potential isolate 1S1 were compatible with their classification in the genus Streptomyces. The 16S rRNA gene sequences have shown that the isolate 1S1 clustered with Streptomyces longisporoflavus. The strain Streptomyces sp. 1S1 was cultivated and extracted with ethyl acetate. The GC–MS study of the extract indicated the presence of certain fatty acyl compounds e.g., tetradecanoic acid, 9-octadecenoic acid, hexadecanoic acid, and 9,12,15-octadecatrienoic acid. Using chromatographic techniques, three compounds were isolated and by spectroscopic methods e.g., IR, MS and NMR structurally elucidated. The three compounds were identified as a triacylglyceride, 9-octadecenoic acid, and hexadecanoic acid. The study reinforces the evidence of the potential of Streptomyces sp and the ability to produce several antimicrobial compounds.

Recycling of Waste Oils: Technology and Application

Reducing the impact of human activity on the environment and, in general, on Earth, represents the most challenging target of the next years [...]

Variation of Used Vegetable Oils’ Composition upon Treatment with Algerian Clays

The treatment of used vegetable oils (UVOs) with clays represents a pivotal step in their industrial recycling process as well as one of the most challenging topics for researchers. In particular, cheap, effective, and sustainable powders need to be explored in order to develop new processes which produce beneficial results in relation to economic and environmental aspects. In this context, five samples within commercial and waste vegetable oils were treated with two sodium- and calcium-based bentonites employing a low oil/bentonite ratio (0.15 wt%). The outcomes of the processes were monitored by FT-IR spectroscopy and compared with the data relative to the parent commercial edible oil. In particular, treatment of FT-IR data by multivariate statistical analysis allowed us to determine a chemical fingerprint characteristic of each sample. Important relationships between the overall chemical composition and the specific clay employed and the treatment time (2 or 4 h) were highlighted. Finally, N2 physisorption, TEM microscopy, and FT-IR analyses of the more efficient Na bentonite allowed us to characterize the material and thus to furnish all the information needed to set-up a general protocol for the partial regeneration of waste vegetable oil destined for further processing.

Optimizing Uniaxial Oil Extraction of Bulk Rapeseeds: Spectrophotometric and Chemical Analyses of the Extracted Oil under Pretreatment Temperatures and Heating Intervals

Optimizing the operating factors in edible oil extraction requires a statistical technique such as a response surface methodology for evaluating their effects on the responses. The examined input factors in this study were the diameter of pressing vessel, VD (60, 80, and 100 mm), temperature, TPR (40, 60, and 80 °C), and heating time, HTM (30, 60 and 90 min). The combination of these factors generated 17 experimental runs where the mass of oil, oil yield, oil extraction efficiency, and deformation energy were calculated. Based on the response surface regression analysis, the combination of the optimized factors was VD: 100 (+1) mm; TPR: 80 °C (+1) and HTM: 60 (0) min); VD: 60 (–1) mm; TPR: 80 °C (+1) and HTM: 75 (+0.5) min and VD: 100 (+1) mm; TPR: 80 °C (+1) and HTM: 90 (+1). The absorbance and transmittance values significantly (p < 0.05) correlated with the wavelength and temperature, but they did not correlate significantly (p > 0.05) with heating time. The peroxide value did not correlate significantly with temperature, however, it correlated significantly with heating time. Neither the acid value nor the free fatty acid value correlated with both temperature and heating time. The findings of the present study are part of our continuing research on oilseeds’ processing optimization parameters.

Multidentate ligand approach for conjugation of perovskite quantum dots to biomolecules

Building compatible surface on perovskite quantum dots (PQDs) for applications like sensing analytes in aqueous medium is highly challenging and if achieved by simple means can revolutionize disease diagnostics. The present work reports the surface engineering of CsPbBr₃ QDs via "simple ligand exchange process" to achieve water-compatible QDs towards detection of biomolecules. The monodentate oleic acid ligand in CsPbBr₃ QDs is exchanged with dicarboxylic acid containing (bidentate) ligands such as folic acid (FA), ethylenediamine tetra-acetic acid (EDTA), succinic acid (SA) and glutamic acid (GA) to develop an efficient water-compatible PQD-ligand system. optical and theoretical studies showed the existence of a stronger binding between the perovskite and succinic acid ligand as compared to oleic acid (OA) and all other ligands. Replacement of OA with SA and retention of crystal structure is validated using spectroscopic and microscopic tools. It is observed that SA ligands facilitate better electronic coupling with PQDs and show significant improvement in fluorescence and stability. Further N-Hydroxy succinimide (NHS), which is a well-known compound to activate carboxyl groups, is used to bind onto SA PQDs as multidentate ligand, to form water stable PQDs. SA PQDs react with NHS (in water) to form multidentate ligand passivated PQDs that show very high photoluminescence (PL) as compared to OA PQDs in toluene. This also results in the formation of an NHS ester that allows bioconjugation with PQDs. This simple probe in water is further utilized for sensing a highly hydrophilic bovine serum albumin (BSA) protein as a model target to demonstrate the potential and effectiveness of this process to create compatible QDs for the successful conjugation of biomolecules. Although the focus of this work is to demonstrate bioconjugation and not achieving higher sensitivity levels, the intrinsic sensing level of these compatible QDs towards BSA shows a detection limit of 51.47 nM, which is above par with other reports in literature.

Beneficial Effects of Cyclic Ether 2-Butoxytetrahydrofuran from Sea Cucumber Holothuria scabra against Aβ Aggregate Toxicity in Transgenic Caenorhabditis elegans and Potential Chemical Interaction

The pathological finding of amyloid-β (Aβ) aggregates is thought to be a leading cause of untreated Alzheimer’s disease (AD). In this study, we isolated 2-butoxytetrahydrofuran (2-BTHF), a small cyclic ether, from Holothuria scabra and demonstrated its therapeutic potential against AD through the attenuation of Aβ aggregation in a transgenic Caenorhabditis elegans model. Our results revealed that amongst the five H. scabra isolated compounds, 2-BTHF was shown to be the most effective in suppressing worm paralysis caused by Aβ toxicity and in expressing strong neuroprotection in CL4176 and CL2355 strains, respectively. An immunoblot analysis showed that CL4176 and CL2006 treated with 2-BTHF showed no effect on the level of Aβ monomers but significantly reduced the toxic oligomeric form and the amount of 1,4-bis(3-carboxy-hydroxy-phenylethenyl)-benzene (X-34)-positive fibril deposits. This concurrently occurred with a reduction of reactive oxygen species (ROS) in the treated CL4176 worms. Mechanistically, heat shock factor 1 (HSF-1) (at residues histidine 63 (HIS63) and glutamine 72 (GLN72)) was shown to be 2-BTHF’s potential target that might contribute to an increased expression of autophagy-related genes required for the breakdown of the Aβ aggregate, thus attenuating its toxicity. In conclusion, 2-BTHF from H. scabra could protect C. elegans from Aβ toxicity by suppressing its aggregation via an HSF-1-regulated autophagic pathway and has been implicated as a potential drug for AD.

Seeking a Fast Screening Method of the Varietal Origin of Olive Oil: The Usefulness of an NMR-Based Approach

This work encompasses the use of 1D multinuclear NMR spectroscopy, namely, ¹H NMR and ¹³C NMR DEPT 45, combined with a multivariate statistical analysis to characterize olive oils produced from nine different varieties: Galega Vulgar, Cobrançosa, Cordovil de Serpa, Blanqueta, Madural, Verdeal Alentejana, Arbequina, Picual and Carrasquenha. Thus, the suitability of an NMR-based spectroscopic tool to discriminate olive oils according to their varietal origin is addressed. The results obtained show that the model based on ¹³C NMR DEPT 45 data has a stronger performance than the model based on ¹H NMR data, proving to be promising in the discrimination of the olive oils under study based on their varietal origin, being particularly relevant for olive oils of the Galega Vulgar variety.

Sustainable Synthesis of Omega-3 Fatty Acid Ethyl Esters from Monkfish Liver Oil

The search for economic and sustainable sources of polyunsaturated fatty acids (PUFAs) within the framework of the circular economy is encouraged by their proven beneficial effects on health. The extraction of monkfish liver oil (MLO) for the synthesis of omega-3 ethyl esters was performed to evaluate two blending systems and four green solvents in this work. Moreover, the potential solubility of the MLO in green solvents was studied using the predictive simulation software COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS). The production of ethyl esters was performed by one or two-step reactions. Novozym 435, two resting cells (Aspergillus flavus and Rhizopus oryzae) obtained in our laboratory and a mix of them were used as biocatalysts in a solvent-free system. The yields for Novozym 435, R. oryzae and A. flavus in the one-step esterification were 63, 61 and 46%, respectively. The hydrolysis step in the two-step reaction led to 83, 88 and 93% of free fatty acids (FFA) for Novozym 435, R. oryzae and A. flavus, respectively. However, Novozym 435 showed the highest yield in the esterification step (85%), followed by R. oryzae (65%) and A. flavus (41%). Moreover, selectivity of polyunsaturated fatty acids of R. oryzae lipase was evidenced as it slightly esterified docosahexaenoic acid (DHA) in all the esterification reactions tested.

Effect of Storage Time on the Physicochemical Properties of Waste Fish Oils and Used Cooking Vegetable Oils

Waste fish oils (FOs) and used cooking vegetable oils (UCOs) are increasingly becoming alternative renewable fuels. However, different physicochemical aspects of these renewable fuels, including the effect of storage, are not well-known. In this work, the effect of the storage period on physicochemical properties of selected samples of FOs and UCOs was investigated. The bio-oils were stored at 4 °C for up to five years before each experimentation. The chemical properties were characterized using capillary gas chromatography with flame ionization detection (GC-FID) and high-performance size exclusion chromatography including an evaporative light scattering detector (HPSEC-ELSD). Water contents and acid numbers of the bio-oils were determined using the Karl Fischer (KF) titration and the ASTM D 664 methods. Furthermore, the average heating values and surface tension of the bio-oils were determined. According to the results obtained, for all bio-oil types, the concentrations of polymerized triglycerides, diglycerides, and fatty acids and monoglycerides had increased during the storage periods. The physical properties of the bio-oils also showed a small variation as a function of the storage period. The overall results observed indicate that the deterioration of the physicochemical properties of bio-oils can be controlled through storage in dark, dry, and cold conditions.

European Union Legislation Overview about Used Vegetable Oils Recycling: The Spanish and Italian Case Studies

The employment of used vegetable oils (UVOs) as raw materials in key sectors as energy production or bio-lubricant synthesis represents one of the most relevant priorities in the European Union (EU) normative context. In many countries, the development of new production processes based on the circular economy model, as well as the definition of future energy and production targets, involve the utilization of wastes as raw material. In this context, the main currently applied EU regulations are presented and discussed. As in the EU, the general legislative process consists of the definition in each State Member of specific legislation, which transposes the EU indications. Two relevant countries are herein considered: Italy and Spain. Through the analysis of the conditions required in both countries for UVOs’ collection, disposal, storage, and recycling, a wide panorama of the current situation is provided.