Sah Ismail Kirbaslar

This study aimed to optimize microwave‐assisted extraction (MAE) and ultrasound‐assisted extraction (UAE) of bioactive compounds from the leaves of Vitex agnus‐castus using deep eutectic solvents (DES). Response surface methodology (RSM) was applied to determine optimal extraction conditions. ChCl:TetEG:H ₂ O was selected as the optimal DES for MAE, while ChCl:TriEG:H ₂ O was identified as the most suitable solvent for UAE. The physicochemical properties of DES, including FTIR spectra, viscosity, pH, and density, were characterized. Optimal MAE conditions were predicted as a microwave power of 293 W, an extraction time of 119 s, and a liquid‐to‐solid (L/S) ratio of 25.12, whereas optimal UAE conditions were 501.96 W, 23.27 min, and an L/S ratio of 70.08. Antioxidant activities (TAC, DPPH, and ABTS) of DES extracts were compared with those obtained using 70% ethanol under optimal MAE and UAE conditions. Phenolic and flavonoid compounds were quantified by HPLC, including caffeic, syringic, p ‐coumaric, and ferulic acids, as well as rutin, myricetin, quercetin, and kaempferol. In addition, the antibacterial activities of the extracts were evaluated. The results demonstrate the effectiveness of optimized MAE and UAE combined with DES for the comprehensive recovery of bioactive compounds from Vitex agnus‐castus .

In this study, the most effective deep eutectic solvent (DES) for extracting antioxidants from purple onion peel was identified using total antioxidant capacity (TAC) values obtained by the CUPRAC assay. The DES systems used in this study cons...

In this study, the reactive extraction of protocatechuic acid (PCA) was investigated with different solvents using tributyl phosphate (TBP). At the end of the studies, the best result was obtained in diisobutyl ketone (DIBK)-TBP combination with 98.70% yield. In the continuation of the study, the effect of different parameters for the reactive extraction of protocatechuic acid from aqueous solutions in the presence of tributyl phosphate using DIBK was investigated. It aimed to find the optimum values by performing experiments that changed the initial acid concentration, water phase: organic phase ratio, and temperature values. As a result of temperature studies, the enthalpy (ΔH) value was calculated as negative, which indicates that the reaction is exothermic. Also, Gibbs free energy (ΔG) gave negative values at the studied temperatures, indicating that the reaction occurs spontaneously. The best extraction yield was obtained with 99.01% at 0.01 mol/L initial acid concentration and a 3:5 water phase to organic phase ratio. In the studies in which the effect of temperature was examined, the highest yield (E%) was obtained with a value of 95.59%. The study was conducted at 293.15 K temperature with 0.01 mol/L initial acid concentration.

In this study, bioactive compounds from Coriandrum sativum seeds were extracted by microwave assisted extraction (MAE) using natural deep eutectic solvents (NADESs). The total antioxidant capacity (TAC) of extracts was determined by using cupric reducing antioxidant capacity (CUPRAC) method. 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) analyses have been employed to measure the free radical scavenging ability of the sample extracts. Five different deep eutectic solvents, using choline chloride in combination with hydrogen bond donors (three polyalcohols and two organic acids) were firstly scanned. Choline chloride and 1,4-butanediol at the molar ratio of 1:4 was the best solvent of choice to extract natural antioxidants to achieve the best level of TAC. The response surface methodology (RSM) was applied to achieve the most advantageous conditions. The optimal process conditions for the maximum TAC value were as follows: 326 watt microwave power, 88 second extraction time, and 10 liquid/solid (L/S) ratio. In this study, we report an efficient, rapid, and green method to extract natural antioxidants from Turkish Coriandrum sativum seeds.

This paper presents a study of the recovering of polyphenols from grapefruit biowastes through extraction and batch adsorption process using novel resin-loaded cationic hydrogel. To prepare adsorbent, 2-(dimethylamino) ethyl methacrylate (DMAEMA) monomer was polymerized by free radical mechanisms in presence of resin particles and then tertiary amino groups on PDMAEMA residue were quaternized using methyl iodide. The developed adsorbent was then characterized by FTIR, SEM, XRD, and Brunauer, Emmet, and Teller analysis. The resin-loaded cationic hydrogel displayed an enhanced affinity for binding with polyphenols at pH value of 10 due to the strong electrostatic attraction between positively charged adsorbent surface and solute molecules. The adsorption capacity of 60 (mg-naringin-g⁻¹-adsorbent) was obtained when the other experimental conditions were chosen as follows: initial polyphenol concentration; 0.13 g mL⁻¹, contact time; 30 min, temperature; 25°C. On the other hand, the adsorbent consisting solely of resin particles shown lower affinity for polyphenols. The adsorption results revealed that the resin-loaded cationic hydrogels exhibited significant improvement in the recovery of polyphenols from grapefruit peels through integrated extraction–adsorption process.

BACKGROUND: The extraction of phenolic compounds from grapefruit leaves assisted by ultrasound‐assisted extraction (UAE) was optimized using response surface methodology (RSM) by means of D‐optimal experimental design and artificial neural network (ANN). For this purpose, five numerical factors were selected: ethanol concentration (0–50%), extraction time (15–60 min), extraction temperature (25–50 °C), solid:liquid ratio (50–100 g L⁻¹) and calorimetric energy density of ultrasound (0.25–0.50 kW L⁻¹), whereas ultrasound probe horn diameter (13 or 19 mm) was chosen as categorical factor.RESULTS: The optimized experimental conditions yielded by RSM were: 10.80% for ethanol concentration; 58.52 min for extraction time; 30.37 °C for extraction temperature; 52.33 g L⁻¹ for solid:liquid ratio; 0.457 kW L⁻¹ for ultrasonic power density, with thick probe type. Under these conditions total phenolics content was found to be 19.04 mg gallic acid equivalents g⁻¹ dried leaf.CONCLUSION: The same dataset was used to train multilayer feed‐forward networks using different approaches via MATLAB, with ANN exhibiting superior performance to RSM (differences included categorical factor in one model and higher regression coefficients), while close values were obtained for the extraction variables under study, except for ethanol concentration and extraction time. © 2018 Society of Chemical Industry