The Infestation of Olive Fruits by Bactrocera oleae (Rossi) Modifies the Expression of Key Genes in the Biosynthesis of Volatile and Phenolic Compounds and Alters the Composition of Virgin Olive Oil

Bactrocera oleae, the olive fruit fly, is one of the most important pests affecting the olive fruit, causing serious quantitative and qualitative damage to olive oil production. In this study, the changes induced by B. oleae infestation in the biosynthesis of volatile and phenolic compounds in olive (cvs. Picual, Manzanilla, and Hojiblanca) have been analyzed. Despite cultivar differences, the oils obtained from infested fruits showed a significant increase in the content of certain volatile compounds such as (E)-hex-2-enal, ethanol, ethyl acetate, and β-ocimene and a drastic decrease of the phenolic contents. The impact of those changes on the inferred quality of the oils has been studied. In parallel, the changes induced by the attack of the olive fly on the expression of some key genes in the biosynthesis of volatile and phenolic compounds, such as lipoxygenase, β-glucosidase, and polyphenol oxidase, have been analyzed. The strong induction of a new olive polyphenol oxidase gene (OePPO2) explains the reduction of phenolic content in the oils obtained from infested fruits and suggest the existence of a PPO-mediated oxidative defense system in olives.     

Application of Cyclodextrins to the Extraction of Antioxidant Compounds from Olive Oil

Olive oil contains powerful antioxidant compounds which impart stability, contribute to various properties of it, and are valuable from the nutritional point of view. Their extraction with as mild conditions as possible led to its investigation using cyclodextrins as a tool. The inclusion ability of α-, β-, and γ-CD was estimated, and it has been demonstrated that the small cavity of α-CD as well as the wide one of γ-CD could enclose less effectively the antioxidant compounds of olive oil than the intermediate in shape cavity of β-CD. The highest yields of antioxidant compounds were achieved when olive oil was mixed with a 2%aqueous solution of β-CD and the resulting precipitate was treated with ethyl alcohol.__________Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 18–21, January–February, 2005.     

Quick assessment of the economic value of olive mill waste water

Background

Olive biophenols are emerging as a valued class of natural products finding practical application in the food, pharmaceutical, beverage, cosmetic and nutraceutical industries due to their powerful biological activity which includes antioxidant and antimicrobial properties. Olive mill waste water (OMWW), a by-product in olive oil manufacturing, is rich in biophenols such as hydroxytyrosol and tyrosol. The amount of biophenols depends on the cultivar, the geographical area of cultivation, and the seasonal conditions. The goal of this study was to develop a straightforward method to assess the economic value of OMWW via quantification of hydroxytyrosol and tyrosol.

Results

The amount of hydroxytyrosol and tyrosol phenolic compounds in the OMWW from four different cultivars grown in four different regions of Sicily was analyzed using liquid–liquid and solid–liquid analytical protocols developed ad hoc. Results showed significant differences amongst the different cultivars and their geographical origin. In all samples, the concentration of hydroxytyrosol was generally from 2 to 10 times higher than that of tyrosol. In general, the liquid–liquid extraction protocol gave higher amounts of extracted biophenols. The cultivar Cerasuola had the highest amount of both hydroxytyrosol and tyrosol. The cultivar Nocellara Etnea had the lowest content of both biophenols.

Conclusions

A quick method to assess the economic value of olive mill waste water via quantification of hydroxytyrosol and tyrosol in olive phenolic enriched extracts is now available.

     

Green Synthesis of Indeno[1,2-b]quinoxalines Using β-Cyclodextrin as Catalyst

An efficient, mild, and green method was developed for the synthesis of indeno[1,2-b]quinoxaline derivatives via o-phenylenediamine (OPD) and 2-indanone derivatives utilizing β-cyclodextrin (β-CD) as the supramolecular catalyst. The reaction can be carried out in water and in a solid state at room temperature. β-CD can also catalyze the reaction of indan-1,2-dione with OPD with a high degree of efficiency. Compared to the reported methods, this procedure is milder, simpler, and less toxic, making it an eco-friendly alternative. In addition, the β-CD can be recovered and reused without the loss of activity.     

Comprehensive Characterisation of the Ketoprofen-β-Cyclodextrin Inclusion Complex Using X-ray Techniques and NMR Spectroscopy

Racemic ketoprofen (KP) and β-cyclodextrin (β-CD) powder samples from co-precipitation (1), evaporation (2), and heating-under-reflux (3) were analysed using X-ray techniques and nuclear magnetic resonance (NMR) spectroscopy. On the basis of NMR studies carried out in an aqueous solution, it was found that in the samples obtained by methods 1 and 2, there were large excesses of β-CD in relation to KP, 10 and 75 times, respectively, while the sample obtained by method 3 contained equimolar amounts of β-CD and KP. NMR results indicated that KP/β-CD inclusion complexes were formed and the estimated binding constants were approximately 2400 M⁻¹, showing that KP is quite strongly associated with β-CD. On the other hand, the X-ray single-crystal technique in the solid state revealed that the (S)-KP/β-CD inclusion complex with a stoichiometry of 2:2 was obtained as a result of heating-under-reflux, for which the crystal and molecular structure were examined. Among the methods used for the preparation of the KP/β-CD complex, only method 3 is suitable.     

Novel Processes for the Extraction of Phenolic Compounds from Olive Pomace and Their Protection by Encapsulation

Olive pomace, the solid by-product derived from olive oil production consists of a high concentration of bioactive compounds with antioxidant activity, such as phenolic compounds, and their recovery by applying innovative techniques is a great opportunity and challenge for the olive oil industry. This study aimed to point out a new approach for the integrated valorization of olive pomace by extracting the phenolic compounds and protecting them by encapsulation or incorporation in nanoemulsions. Innovative assisted extraction methods were evaluated such as microwave (MAE), homogenization (HAE), ultrasound (UAE), and high hydrostatic pressure (HHPAE) using various solvent systems including ethanol, methanol, and natural deep eutectic solvents (NADESs). The best extraction efficiency of phenolic compounds was achieved by using NADES as extraction solvent and in particular the mixture choline chloride-caffeic acid (CCA) and choline chloride-lactic acid (CLA); by HAE at 60 °C/12,000 rpm and UAE at 60 °C, the total phenolic content (TPC) of extracts was 34.08 mg gallic acid (GA)/g dw and 20.14 mg GA/g dw for CCA, and by MAE at 60 °C and HHPAE at 600 MPa/10 min, the TPC was 29.57 mg GA/g dw and 25.96 mg GA/g dw for CLA. HAE proved to be the best method for the extraction of phenolic compounds from olive pomace. Microencapsulation and nanoemulsion formulations were also reviewed for the protection of the phenolic compounds extracted from olive pomace. Both encapsulation techniques exhibited satisfactory results in terms of encapsulation stability. Thus, they can be proposed as an excellent technique to incorporate phenolic compounds into food products in order to enhance both their antioxidative stability and nutritional value.     

β-Cyclodextrin Derivative Grafted on Silica Gel Represents a New Polymeric Sorbent for Extracting Nitisinone from Model Physiological Fluids

Nitisinone (NTBC) is used in the treatment of disorders affecting the tyrosine pathway, including hereditary tyrosinemia type I, alkaptonuria, and neuroblastoma. An inappropriate dosage of this therapeutic drug causes side effects; therefore, it is necessary to develop a rapid and sensitive method to monitor the content of NTBC in patients’ blood. This study aimed to develop anew polymeric sorbent containing β-cyclodextrin (β-CD) derivatives grafted on silica gel to effectively extract NTBC from model physiological fluids. The inclusion complex formed between β-CD and NTBC was examined by proton nuclear magnetic resonance spectroscopy. The novel sorbents with derivatives of β-CD were prepared on modified silica gel using styrene as a comonomer, ethylene glycol dimethacrylate as a crosslinking agent, and 2,2′-azo-bis-isobutyronitrile as a polymerization initiator. The obtained products were characterized via Fourier transform infrared spectroscopy and then used as sorbents as part of a solid phase extraction technique. High NTBC recovery (70%indicated that the developed polymeric sorbent may be suitable for extracting this compound from patients’ blood samples.     

Development of Analytical Strategies for the Determination of Olive Fruit Bioactive Compounds Using UPLC-HRMS and HPLC-DAD. Chemical Characterization of Kolovi Lesvos Variety as a Case Study

In this study, an overall survey regarding the determination of several bioactive compounds in olive fruit is presented. Two methodologies were developed, one UPLC-Q-TOF-MS method for the determination of olive fruit phenolic compounds and one HPLC-DAD methodology targeting the determination of pigments (chlorophylls and carotenoids), tocopherols (α-, β, -γ, δ-) and squalene. Target and suspect screening workflows were developed for the thorough fingerprinting of the phenolic fraction of olives. Both methods were validated, presenting excellent performance characteristics, and can be used as reliable tools for the monitoring of bioactive compounds in olive fruit samples. The developed methodologies were utilized to chemical characterize the fruits of the Kolovi olive variety, originating from the island of Lesvos, North Aegean Region, Greece. Twenty-five phenolic compounds were identified and quantified in Kolovi olives with verbascoside, hydroxytyrosol, oleacein and oleomissional found in significantly high concentrations. Moreover, 12 new bioactive compounds were identified in the samples using an in-house suspect database. The results of pigments analysis suggested that Kolovi variety should be characterized as low pigmentation, while the tocopherol and squalene content was relatively high compared to other olive varieties. The characterization of Kolovi olive bioactive content highlighted the high nutritional and possible economic value of the Kolovi olive fruit.     

Biogas Potential of the Side Streams Obtained in a Novel Phenolic Extraction System from Olive Mill Solid Waste

The olive oil production is an important industrial sector in many Mediterranean areas, but it is currently struggled by the necessity of a proper valorisation of the olive mill solid waste or alperujo. The alperujo is the main by-product generated during the two-phase olive oil extraction, accounting for up to 80% of the initial olive mass. The alperujo is a source of valuable compounds, such as the pomace olive oil or highly interesting phenolic compounds. In the present research, a novel biorefinery approach has been used for phenolic compounds recovery. However, the extraction of these valuables compounds generates different exhausted phases with high organic matter content that are required to be managed. This study consists of the evaluation of the anaerobic biodegradability of the different fractions obtained in a novel biorefinery approach for the integral valorisation of alperujo. The results show that the different phases obtained during the biorefinery of the alperujo can be effectively subjected to anaerobic digestion and no inhibition processes were detected. The highest methane yield coefficients were obtained for the phases obtained after a two-months storages, i.e., suspended solids and liquid phase free of suspended solids, which generated 366 ± 7 mL CH₄/g VS and 358 ± 6 mL CH₄/g VS, respectively. The phenol extraction process reduced the methane yield coefficient around 25% due to the retention of biodegradable compounds during the extraction process. Regardless of this drop, the anaerobic digestion is a suitable technology for the stabilization of the different generated residual phases, whereas the high market price of the extracted phenols can largely compensate the slight decrease in the methane generation.     

Optimising the Polyphenolic Content and Antioxidant Activity of Green Rooibos (Aspalathus linearis) Using Beta-Cyclodextrin Assisted Extraction

Antioxidant activity associated with green rooibos infusions is attributed to the activity of polyphenols, particularly aspalathin and nothofagin. This study aimed to optimise β-cyclodextrin (β-CD)-assisted extraction of crude green rooibos (CGRE) via total polyphenolic content (TPC) and antioxidant activity assays. Response surface methodology (RSM) permitted optimisation of β-CD concentration (0–15 mM), temperature (40–90 °C) and time (15–60 min). Optimal extraction conditions were: 15 mM β-CD: 40 °C: 60 min with a desirability of 0.985 yielding TPC of 398.25 mg GAE·g⁻¹, metal chelation (MTC) of 93%, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging of 1689.7 µmol TE·g⁻¹, ferric reducing antioxidant power (FRAP) of 2097.53 µmol AAE·g⁻¹ and oxygen radical absorbance capacity (ORAC) of 11,162.82 TE·g⁻¹. Aspalathin, hyperoside and orientin were the major flavonoids, with quercetin, luteolin and chrysoeriol detected in trace quantities. Differences (p < 0.05) between aqueous and β-CD assisted CGRE was only observed for aspalathin reporting the highest content of 172.25 mg·g⁻¹ of dry matter for extracts produced at optimal extraction conditions. Positive, strong correlations between TPC and antioxidant assays were observed and exhibited regression coefficient (R²) between 0.929–0.978 at p < 0.001. These results demonstrated the capacity of β-CD in increasing polyphenol content of green rooibos.     

Release of Cinnamaldehyde and Thymol from PLA/Tilapia Fish Gelatin-Sodium Alginate Bilayer Films to Liquid and Solid Food Simulants,and Japanese Sea Bass: A Comparative Study

This study aimed to develop an active biodegradable bilayer film and to investigate the release behaviors of active compounds into different food matrices. Cinnamaldehyde (CI) or thymol (Ty) was encapsulated in β-cyclodextrin (β-CD) to prepare the active β-CD inclusion complex (β-CD-CI/β-CD-Ty). The tilapia fish gelatin-sodium alginate composite (FGSA) containing β-CD-CI or β-CD-Ty was coated on the surface of PLA film to obtain the active bilayer film. Different food simulants including liquid food simulants (water, 3% acetic acid, 10% ethanol, and 95% ethanol), solid dry food simulant (modified polyphenylene oxide (Tenax TA)), and the real food (Japanese sea bass) were selected to investigate the release behaviors of bilayer films into different food matrixes. The results showed that the prepared β-CD inclusion complexes distributed evenly in the cross-linking structure of FGSA and improved the thickness and water contact angle of the bilayer films. Active compounds possessed the lowest release rates in Tenax TA, compared to the release to liquid simulants and sea bass. CI and Ty sustained the release to the sea bass matrix with a similar behavior to the release to 95% ethanol. The bilayer film containing β-CD-Ty exhibited stronger active antibacterial and antioxidant activities, probably due to the higher release efficiency of Ty in test mediums.     

Encapsulation of α-Pinene in Delivery Systems Based on Liposomes and Cyclodextrins

The essential oil component α-pinene has multiple biological activities. However, its application is limited owing to its volatility, low aqueous solubility, and chemical instability. For the aim of improving its physicochemical properties, α-pinene was encapsulated in conventional liposomes (CLs) and drug-in-cyclodextrin-in-liposomes (DCLs). Hydroxypropyl-β-cyclodextrin/α-pinene (HP-β-CD/α-pinene) inclusion complexes were prepared in aqueous solution, and the optimal solubilization of α-pinene occurred at HP-β-CD:α-pinene molar ratio of 7.5:1. The ethanol-injection method was applied to produce different formulations using saturated (Phospholipon 90H) or unsaturated (Lipoid S100) phospholipids in combination with cholesterol. The size, the phospholipid and cholesterol incorporation rates, the encapsulation efficiency (EE), and the loading rate (LR) of α-pinene were determined, and the storage stability of liposomes was assessed. The results showed that α-pinene was efficiently entrapped in CLs and DCLs with high EE values. Moreover, Lipoid S100 CLs displayed the highest LR (22.9 ± 2.2%) of α-pinene compared to the other formulations. Both carrier systems HP-β-CD/α-pinene inclusion complex and Lipoid S100 CLs presented a gradual release of α-pinene. Furthermore, the DPPH radical scavenging activity of α-pinene was maintained upon encapsulation in Lipoid S100 CLs. Finally, it was found that all formulations were stable after three months of storage at 4 °C.     

On Complex Formation between 5-Fluorouracil and β-Cyclodextrin in Solution and in the Solid State: IR Markers and Detection of Short-Lived Complexes by Diffusion NMR

In this work, the nuclear magnetic resonance (NMR) and IR spectroscopic markers of the complexation between 5-fluorouracil (5-FU) and β-cyclodextrin (β-CD) in solid state and in aqueous solution are investigated. In the attenuated total reflectance(ATR) spectra of 5-FU/β-CD products obtained by physical mixing, kneading and co-precipitation, we have identified the two most promising marker bands that could be used to detect complex formations: the C=O and C-F stretching bands of 5-FU that experience a blue shift by ca. 8 and 2 cm⁻¹ upon complexation. The aqueous solutions were studied by NMR spectroscopy. As routine NMR spectra did not show any signs of complexation, we have analyzed the diffusion attenuation of spin–echo signals and the dependence of the population factor of slowly diffusing components on the diffusion time (diffusion NMR of pulsed-field gradient (PFG) NMR). The analysis has revealed that, at each moment, ~60% of 5-FU molecules form a complex with β-CD and its lifetime is ca. 13.5 ms. It is likely to be an inclusion complex, judging from the independence of the diffusion coefficient of β-CD on complexation. The obtained results could be important for future attempts of finding better methods of targeted anticancer drug delivery.     

Oligomer Sensor Nanoarchitectonics for “Turn-On” Fluorescence Detection of Cholesterol at the Nanomolar Level

Sensitive and rapid monitoring of cholesterol levels in the human body are highly desirable as they are directly related to the diagnosis of cardiovascular diseases. By using the nanoarchitectonic approach, a novel fluorescent conjugated oligofluorene (OFP-CD) functionalized with β-cyclodextrin (β-CD) was assembled for “Turn-On” fluorescence sensing of cholesterol. The appended β-CD units in OFP-CD enabled the forming of host-guest complexes with dabsyl chloride moieties in water, resulting in fluorescence quenching of the oligofluorene through intermolecular energy transfer. In the presence of cholesterol molecules, a more favorable host-guest complex with stoichiometry 1 cholesterol: 2 β-CD units was formed, replacing dabsyl chloride in β-CD’s cavities. This process resulted in fluorescence recovery of OFP-CD, owing to disruption of energy transfer. The potential of this nanoarchitectonic system for “Turn-On” sensing of cholesterol was extensively studied by fluorescence spectroscopy. The high selectivity of the sensor for cholesterol was demonstrated using biologically relevant interfering compounds, such as carbohydrates, amino acids, metal ions, and anions. The detection limit (LOD value) was as low as 68 nM, affirming the high sensitivity of the current system.     

Complexation of Cyclodextrins with Benzoic Acid in Water-Organic Solvents: A Solvation-Thermodynamic Approach

The aim of this research is to obtain new data about the complexation between β-cyclodextrin (β-CD) and benzoic acid (BA) as a model reaction of the complex formation of hydrophobic molecules with cyclodextrins (CDs) in various media. This research may help developing cyclodextrin-based pharmaceutical formulations through the choice of the appropriate solvent mixture that may be employed in the industrial application aiming to control the reactions/processes in liquid phase. In this paper, NMR results for the molecular complex formation between BA and β-CD ([BA⊂β-CD]) in D₂O-DMSO-d₆ and in D₂O-EtOH have shown that the stability of the complex in the H₂O-DMSO-d₆ varies within the experimental error, while decreases in H₂O-EtOH. Changes in the Gibbs energy of BA resolvation in water and water–dimethylsulfoxide mixtures have been obtained and have been used in the analysis of the reagent solvation contributions into the Gibbs energy changes of the [BA⊂β-CD] molecular complex formation. Quantum chemical calculations of the interaction energy between β-CD and BA as well as the structure of the [BA⊂β-CD] complex and the energy of β-CD and BA interaction in vacuum and in the medium of water, methanol and dimethylsulfoxide solvents are carried out. The stability of [BA⊂β-CD] complex in H₂O-EtOH and H₂O-DMSO solvents, obtained by different methods, are compared. The thermodynamic parameters of the [BA⊂β-CD] molecular complexation as well as the reagent solvation contributions in H₂O-EtOH and H₂O-DMSO mixtures were analyzed by the solvation-thermodynamic approach.     

HPTLC and FTIR Fingerprinting of Olive Leaves Extracts and ATR-FTIR Characterisation of Major Flavonoids and Polyphenolics

The aim of this study was to analyse the effect of spontaneous microbial maceration on the release and extraction of the flavonoids and phenolics from olive leaves. Bioprofiling based on thin-layer chromatography effect-directed detection followed by ATR-FTIR spectroscopy proved to be a reliable and convenient method for simultaneous comparison of the extracts. Results show that fermentation significantly enhances the extraction of phenolic compounds and flavonoids. The polyphenolic content was increased from 6.7 µg GAE (gallic acid equivalents) to 25.5 µg GAE, antioxidants from 10.3 µg GAE to 25.3 µg GAE, and flavonoid content from 42 µg RE (rutin equivalents) to 238 µg RE per 20 µL of extract. Increased antioxidant activity of fermented ethyl acetate extracts was attributed to the higher concentration of extracted flavonoids and phenolic terpenoids, while increased antioxidant activity in fermented ethanol extract was due to increased extraction of flavonoids as extraction of phenolic compounds was not improved. Lactic acid that is released during fermentation and glycine present in the olive leaves form a natural deep eutectic solvent (NADES) with significantly increased solubility for flavonoids.     

β-Cyclodextrin Inclusion Complexes with Catechol-Containing Antioxidants Protocatechuic Aldehyde and Protocatechuic Acid—An Atomistic Perspective on Structural and Thermodynamic Stabilities

Protocatechuic aldehyde (PCAL) and protocatechuic acid (PCAC) are catechol derivatives and have broad therapeutic effects associated with their antiradical activity. Their pharmacological and physicochemical properties have been improved via the cyclodextrin (CD) encapsulation. Because the characteristics of β-CD inclusion complexes with PCAL (1) and PCAC (2) are still equivocal, we get to the bottom of the inclusion complexation by an integrated study of single-crystal X-ray diffraction and DFT full-geometry optimization. X-ray analysis unveiled that PCAL and PCAC are nearly totally shielded in the β-CD wall. Their aromatic rings are vertically aligned in the β-CD cavity such that the functional groups on the opposite side of the ring (3,4-di(OH) and 1-CHO/1-COOH groups) are placed nearby the O6–H and O2–H/O3–H rims, respectively. The preferred inclusion modes in 1 and 2 help to establish crystal contacts of OH⋅⋅⋅O H-bonds with the adjacent β-CD OH groups and water molecules. By contrast, the DFT-optimized structures of both complexes in the gas phase are thermodynamically stable via the four newly formed host–guest OH⋯O H-bonds. The intermolecular OH⋅⋅⋅O H-bonds between PCAL/PCAC 3,4-di(OH) and β-CD O6–H groups, and the shielding of OH groups in the β-CD wall help to stabilize these antioxidants in the β-CD cavity, as observed in our earlier studies. Moreover, PCAL and PCAC in distinct lattice environments are compared for insights into their structural flexibility.     

A Novel Solid Nanocrystals Self-Stabilized Pickering Emulsion Prepared by Spray-Drying with Hydroxypropyl-β-cyclodextrin as Carriers

A drug nanocrystals self-stabilized Pickering emulsion (NSSPE) with a unique composition and microstructure has been proven to significantly increase the bioavailability of poorly soluble drugs. This study aimed to develop a new solid NSSPE of puerarin preserving the original microstructure of NSSPE by spray-drying. A series of water-soluble solid carriers were compared and then Box-Behnken design was used to optimize the parameters of spray-drying. The drug release and stability of the optimized solid NSSPE in vitro were also investigated. The results showed that hydroxypropyl-β-cyclodextrin (HP-β-CD), rather than solid carriers commonly used in solidification of traditional Pickering emulsions, was suitable for the solid NSSPE to retain the original appearance and size of emulsion droplets after reconstitution. The amount of HP-β-CD had more influences on the solid NSSPE than the feed rate and the inlet air temperature. Fluorescence microscopy, confocal laser scanning microscopy and scanning electron microscopy showed that the reconstituted emulsion of the solid NSSPE prepared with HP-β-CD had the same core-shell structure with a core of oil and a shell of puerarin nanocrystals as the liquid NSSPE. The particle size of puerarin nanocrystal sand interfacial adsorption rate also did not change significantly. The cumulative amount of released puerarin from the solid NSSPE had no significant difference compared with the liquid NSSPE, which were both significantly higher than that of puerarin crude material. The solid NSSPE was stable for 3 months under the accelerated condition of 75% relative humidity and 40 °C. Thus, it is possible todevelop the solid NSSPE preserving the unique microstructure and the superior properties in vitro of the liquid NSSPE for poorly soluble drugs.     

Choline Chloride–Lactic Acid-Based NADES As an Extraction Medium in a Response Surface Methodology-Optimized Method for the Extraction of Phenolic Compounds from Hazelnut Skin

Deep eutectic solvents (DESs) are promising green solvents for the extraction of compounds from food byproducts. Hazelnut (Corylus avellana L.) is one of the most commonly cultivated tree nuts worldwide. The skin represents one of the major byproducts of the hazelnut industry and accounts for 2.5% of the total hazelnut kernel weight. It is a rich source of phenolic compounds like flavan-3-ols, flavonols, dihydrochalcones, and phenolic acids. In this work, fifteen DESs based on choline chloride and betaine, with different compositions, were studied in order to test their phenolic compounds extraction efficiency through the determination of their total concentration via Folin–Ciocalteu assay. A qualitative analysis of extracted phenolic compounds was assessed by HPLC with UV and MS detection. Using the DES with the best extraction efficiency, a new ultrasound-assisted solid liquid extraction (UA-SLE) method was optimized though the response surface methodology (RSM), taking into account some extraction parameters. Efficient recovery of extracted phenolic compounds was achieved using a 35% water solution of choline chloride and lactic acid (molar ratio 1:2) as an extraction solvent, working at 80 °C and with a solid-to-solvent ratio of 1:25 gmL⁻¹. The optimized conditions made it possible to recover 39% more phenolic compounds compared to a classic organic solvent.     

β-Cyclodextrin-Polyacrylamide Hydrogel for Removal of Organic Micropollutants from Water

Water pollution by various toxic substances remains a serious environmental problem, especially the occurrence of organic micropollutants including endocrine disruptors, pharmaceutical pollutants and naphthol pollutants. Adsorption process has been an effective method for pollutant removal in wastewater treatment. However, the thermal regeneration process for the most widely used activated carbon is costly and energy-consuming. Therefore, there has been an increasing need to develop alternative low-cost and effective adsorption materials for pollutant removal. Herein, β-cyclodextrin (β-CD), a cheap and versatile material, was modified with methacrylate groups by reacting with methacryloyl chloride, giving an average degree of substitution of 3 per β-CD molecule. β-CD-methacrylate, which could function as a crosslinker, was then copolymerized with acrylamide monomer via free-radical copolymerization to form β-CD-polyacrylamide (β-CD-PAAm) hydrogel. Interestingly, in the structure of the β-CD-PAAm hydrogel, β-CD is not only a functional unit binding pollutant molecules through inclusion complexation, but also a structural unit crosslinking PAAm leading to the formation of the hydrogel 3D networks. Morphological studies showed that β-CD-PAAm gel had larger pore size than the control PAAm gel, which was synthesized using conventional crosslinker instead of β-CD-methacrylate. This was consistent with the higher swelling ratio of β-CD-PAAm gel than that of PAAm gel (29.4 vs. 12.7). In the kinetic adsorption studies, phenolphthalein, a model dye, and bisphenol A, propranolol hydrochloride, and 2-naphthol were used as model pollutants from different classes. The adsorption data for β-CD-PAAm gel fitted well into the pseudo-second-order model. In addition, the thermodynamic studies revealed that β-CD-PAAm gel was able to effectively adsorb the different dye and pollutants at various concentrations, while the control PAAm gel had very low adsorption, confirming that the pollutant removal was due to the inclusion complexation between β-CD units and pollutant molecules. The adsorption isotherms of the different dye and pollutants by the β-CD-PAAm gel fitted well into the Langmuir model. Furthermore, the β-CD-PAAm gel could be easily recycled by soaking in methanol and reused without compromising its performance for five consecutive adsorption/desorption cycles. Therefore, the β-CD-PAAm gel, which combines the advantage of an easy-to-handle hydrogel platform and the effectiveness of adsorption by β-CD units, could be a promising pollutant removal system for wastewater treatment applications.