Kinetics of ultrasound assisted extraction of anthocyanins from Aronia melanocarpa (black chokeberry) wastes

Black chokeberry fruits are very rich in antioxidant phenolics. After juice extraction, the wastes of pressed berries (juice production by-products) still contain important amount of phenolic species and namely anthocyanins. Ultrasound assisted extraction (UAE) from such wastes was studied. The influence of extraction time (0–240 min), temperature (20–70 °C), solvent composition (0–50% ethanol in water) and ultrasound power (0–100 W) on anthocyanins and polyphenols yields and on antioxidant capacity of the extracts was studied. High temperature and ethanol content in the solvent improved greatly the extraction yields. Ultrasounds improved mainly the extraction kinetics. Ultrasound effect was higher in the beginning of extraction process and at low temperatures. Suitability of UAE for preparation of antioxidant-rich plant extracts at reduced time and energy was confirmed obtaining high extraction efficiencies and high antioxidant capacities of Aronia extracts. To optimize extraction conditions a kinetic mathematical model, based on Peleg's equation and considering also the rate of anthocyanins thermal degradation, was proposed. The influences of extraction time, temperature, solvent composition and ultrasound power on polyphenols and anthocyanins yields and on antioxidant capacity were considered. The optimal conditions for anthocyanins extraction predicted by this model were experimentally validated.     

超声辅助提取落叶松树皮原花青素的工艺研究

对落叶松树皮中原花青素的超声波辅助提取工艺进行了研究,考察了提取温度、料液比、超声时间、溶剂浓度等4个因素对原花青素提取的影响。在单因素试验和正交试验的基础上,优选出超声波辅助提取落叶松树皮原花青素的最佳工艺条件为:以60%的乙醇溶液为溶剂,在50℃、料液比1∶25(g/mL)的条件下,用200 W的超声功率作用辅助提取60 min,原花青素的提取率可以达到1.0512%。     

Chestnut bark tannin assays and growth of chestnut blight fungus on extracted tannin

Tannins extracted from the green bark of each of two Chinese, Japanese, and American chestnut trees were assayed in a protein-binding test. Four levels of tannins were added to a buffered, minimal growth medium, and a standard, virulent strain of the chestnut blight fungus was grown. There were only slight differences in protein binding between the extracts from different species. Fungal growth was better with tannin than without, but there was no difference between species extracts in their ability to improve fungal growth rate. There was also no inhibition of blight fungus growth by any of the tree tannins, so tannin toxicity is not the reason for Asian chestnut tree resistance.     

元宝枫植物单宁的提取及其阳离子改性的研究

采用丙酮-水的混合液提取元宝枫翅果中单宁,再利用甲醛、二甲胺和氯化苄对提取的单宁进行阳离子改性.实验结果发现,当丙酮-水混合液浸提温度为55℃,水与丙酮体积比为1:0.5时,提取效果理想.在单宁的阳离子改性中,发现单宁阳离子化改性的理想反应条件为胺甲基化反应温度85℃,pH 6.0左右,m(单宁):m(二甲胺):m(甲醛)=1:1.5:1,反应时间为3 h,氯化苄季铵化反应温度90℃,m(胺甲基单宁):m(氯化苄)=1:0.8,反应时间2 h.应用结果表明,阳离子改性单宁具有良好的阻垢和缓蚀作用.     

Influence of ultrasound on diffusion through skin/leather matrix

Leather is a unique porous material, which is composed of a three-dimensional weave of tanned collagen fibre bundles. Collagen is a fibrous protein well organized in the formation of skin as building block. This paper studies the use of ultrasound in improving the diffusion process through porous skin/leather matrix. A diffusion model for leather processing has been proposed taking into account of pore characteristics in leather. Dye diffusion experiments have been carried out with leather and powdered leather to show the influence of ultrasound under two different diffusion conditions. Apparent diffusion coefficient (D) of dye through leather matrix has been calculated from the experimental dye uptake data. The results indicate that the use of ultrasound could achieve, 16.2 and 8.56 times improvement in D value for leather at 50 °C and 30 °C, respectively as compared to 2.99 and 1.55 times for powdered leather. Scanning electron microscopy (SEM) analysis of leather has also been performed which shows that fibre structure and morphology are not affected by the use of ultrasound. This study throws some light on enhanced transport through porous materials of complex nature such as skin/leather using ultrasound.     

Recovery of betulinic acid from plane tree (Platanus acerifolia L.)

Betulinic acid (3β, hydroxy-lup-20(29)-en-28-oic acid) is a bioactive triterpenic acid which was identified in various botanical sources and in considerable amounts in the bark of plane tree (Platanus acerifolia L.). In this work, the recovery of betulinic acid from plane tree bark was studied using different liquid solvent based extraction methods, namely solid–liquid extraction (SLE), ultrasound assisted extraction (UAE) and pressurized liquid extraction (PLE). Furthermore, preliminary studies of the supercritical fluid extraction (SFE) of plane tree bark are also reported.The liquid solvent based extraction techniques (SLE, UAE and PLE) were carried out using ethanol and ethyl acetate, and produced a recovery of betulinic acid in the range 10–15 mg/g of bark, with concentrations around 25–35% mass. A betulinic acid enrichment in the ethanolic extracts was possible by means of a simple precipitation step adding water. The precipitate contained 42–46% mass of betulinic acid and high recovery (>95%). Increasing the extraction temperature, by means of the PLE assays, has not resulted in an improvement of betulinic acid recovery.The preliminary SFE assays produced lower recoveries of betulinic acid (0.5–8 mg/g) with respect to liquid extraction. The addition of ethanol as cosolvent produced a significant improvement of both betulinic acid recovery and concentration in the SFE extract.     

Research on extraction of Cr(III) by D2EHPA/n-octanol/sulphonated kerosene

Chromium is an important industrial raw material. As far as China is concerned, chromium is in great demand, which is dependent on imports and large emissions. So recovery of chromium has important economic and environmental protection value. The extraction and back extraction of Cr(III) from solution by the extractant diisooctyl phosphate (di-2-ethylhexylphosphoric acid [D2EHPA]) with n-octanol as assistant and sulphonated kerosene as diluent was studied. The effects of saponification rate, phase ratio, temperature, condensation of extract, aging of extractant, and pH of aqueous phase on extraction equilibrium were discussed, and the formulation of extractant was optimized. The coordination number of the extraction reaction under specific conditions was discussed by the saturation capacity method. The extraction reaction kinetics were mathematically characterized by binary linear regression. The advantages and disadvantages of back extraction with H₂SO₄ or NaOH were compared. At last, a process to realize the recycling of extractant was obtained.     

Impact of ultrasound on oil yield and content of functional food ingredients at the oil extraction from sunflower

In this study, the effect of ultrasound-assisted extraction (UAE) on oil yield and content of functional food ingredients of hulled and non-hulled sunflower is discussed and compared with conventional extraction methods. The optimum extraction parameters for UAE were as follows: n-hexane as extracting solvent, average particle size 250 ± 12 µm, extraction time 2 h, solid-to-solvent ratio 1:12, ultrasound frequency 24 kHz and temperature 50°C. Furthermore, the chromatograph showed that sunflower oil extracted by the UAE was rich in α-Linolenic acid (ω-3). In addition, a marginal reduction in peroxide values and tocopherols were determined.     

Adsorption of bismuth(III) by bayberry tannin immobilized on collagen fiber

The adsorption behavior of collagen fiber‐immobilized bayberry tannin towards Bi(III) at acidic pH values was investigated. The adsorption capacity of the adsorbent towards Bi(III) was 0.348 mmol g^?1 at 303 K, and increased with the rise in temperature. The adsorption isotherms of Bi(III) were in the shape of so‐called type II isotherms and could be described by an empirical equation, ln q_e = k + (1/n)C_e, which implies that chemical adsorption is predominant at lower concentrations of Bi(III) and that physical adsorption is involved at higher concentrations. The adsorption kinetics of Bi(III) on the immobilized bayberry tannin could be well described by the pseudo‐second‐order rate model, and the adsorption capacities calculated by the model were almost the same as those determined by actual measurements. The adsorbent could be regenerated by using 0.02 mol dm^?3 ethylenediaminetetraacetic acid (EDTA) solution after adsorption of Bi(III). The adsorption selectivity of the immobilized bayberry tannin towards Bi(III) in a Cu(II)–Bi(III) binary solution in acidic medium was remarkable. Therefore, it is strongly suggested that the immobilized bayberry tannin could be applied to the removal of Bi(III) from crude Cu(II) samples under proper conditions. Copyright © 2006 Society of Chemical Industry     

Experimental and simulation study of nylon 6 solid–liquid extraction process

The solid–liquid extraction process of nylon 6 to eliminate small molecules, i.e., caprolactam(CL), cyclic dimers(CD) and cyclic trimers(CT), is investigated in detail by both batch extraction experiments and numerical simulations. In the batch extraction experiments, due to the small molecules attaching to the polymeric surface, the basic physical mechanism shifts from surface diffusion to internal diffusion as the extraction proceeded. The experimental data are well reproduced by a diffusion model consisting of two distinct steps, characterized as surface diffusion and internal diffusion. Furthermore, based on the established mass transfer mechanism and diffusion model of the two distinct steps, the equilibrium constants and internal diffusion coefficients of CL, CD and CT are acquired. An industrial countercurrent extraction tower is further simulated. It is found that the extraction efficiency of CL can be significantly improved by increasing the temperature at the bottom portion of the tower. The elimination of CD, which can be greatly promoted by a high-concentration CL-water solution, is controlled by mass transfer resistance, whereas the removal of CL is mainly affected by the equilibrium.     

球形聚合单宁-纤维素树脂的制备及吸附性能

单宁与多聚甲醛交联合成单宁酚醛聚合物,再以环氧氯丙烷为交联剂,将单宁酚醛聚合物与纤维素通过反相悬浮交联制备球形聚合单宁-纤维素树脂。通过傅里叶变换红外光谱（FTIR）、扫描电子显微镜（SEM）对球形聚合单宁-纤维素树脂的结构进行了表征,并考察了球形聚合单宁-纤维素树脂对盐酸小檗碱的吸附性能。结果表明,球形聚合单宁-纤维素树脂具有多孔的结构,树脂网络中含有大量的酚羟基;球形聚合单宁-纤维素树脂对盐酸小檗碱具有较好的吸附性能,当盐酸小檗碱浓度为600 mg·L^-1、吸附温度为298 K时,最大饱和吸附量可达245.92mg·g^-1;球形聚合单宁-纤维素树脂对盐酸小檗碱的吸附过程符合Langmuir吸附等温模型和准二级吸附动力学方程,热力学研究数据表明球形单宁-纤维素树脂对盐酸小檗碱的吸附是一个自发放热的物理吸附过程。该树脂在分离提纯生物碱方面具有潜在的应用前景。     

Performances of larch (larix gmelini) tannin modified urea–formaldehyde (TUF) resin and plywood bonded by TUF resin

Tannin from larch (Larix gmelini) bark extracts, as a natural renewable resource, was used to prepare tannin–urea–formaldehyde (TUF) resin. The chemical structures of larch tannin and TUF resin were characterized by matrix‐assisted laser desorption/ionization‐time of flight mass spectrometry and ¹³C nuclear magnetic resonance. The thermal behaviors of TUF resin were evaluated by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). The performances of TUF resin were investigated by measuring the bond strength and formaldehyde emission of its bonded plywood. It was clearly shown that larch tannin is mainly composed of prodelphinidin repeating units. Phenolic groups were introduced into TUF resin mainly linked by methylene bond. Larch tannin has an adverse effect on the resin curing. However, it promoted the rigidity and flexibility of the glued system and upgraded the properties of plywood. Therefore, larch tannin could be applied in the modification of urea–formaldehyde resin. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41064.     

Phase equilibria of mixtures containing CO2 and organic acids using the UMR-PRU model

The UMR-PRU model, which has been successfully tested in the past to the predictions of different type of phase equilibrium and thermodynamic properties in binary and multicomponent systems, is applied in this work to phase equilibria in mixtures containing CO₂ and organic acids. New interaction parameters are determined by fitting only binary vapor–liquid equilibrium data and then they are used to predict the vapor–liquid, solid–gas and solid–liquid–gas equilibria in CO₂/organic acid systems. Furthermore, the UMR-PRU model with the newly derived interaction parameters is applied to the prediction of the phase equilibrium in ternary mixtures consisting of CO₂, organic acids and water. Satisfactory results are obtained in all cases.     

Cloud point and solvent extraction study of uranium(VI) by 8‐hydroxyquinoline

BACKGROUND: Cloud point extraction (CPE) is an attractive alternative to solvent extraction. However, comparisons between both techniques are lacking. In this paper, the extraction of uranium(VI) using 8‐hydroxyquinoline (HQ) as chelating agent was studied by CPE using Triton X‐114 as non‐ionic surfactant and by solvent extraction using CHCl₃ as diluent. RESULTS: Using CPE, a quantitative extraction was observed for pH higher than 4.5 with a HQ/U ratio of 10. Using solvent extraction an increase in the HQ/U ratio up to 50 is necessary to obtain a near quantitative extraction. Both extraction systems were then compared with respect to the nature of extracted species, and the extraction constants determined using log‐log analysis of the extraction data. In the solvent extraction system, the extracted species were identified as UO₂Q₂ and the corresponding extraction constant was found to be log k_ex = ? 3.6 ± 0.2 on the molar scale. Considering that UO₂Q₂ is also the extracted species in CPE, a slightly higher extraction constant, i.e. log k_ex = ? 2.5 ± 0.3, was found. CONCLUSION: Such a small difference in favour of the CPE system may arise from the combination of various phenomena, including effects of temperature and effects of ‘extractant environment’. However, a change in the nature of the extracted species, namely from UO₂Q₂ in the solvent extraction system to the formation of adducts, i.e. UO₂Q₂(HQ) and UO₂Q₂(HQ)₂ in the CPE system, due to higher HQ concentration in the surfactant‐rich phase compared with chloroform, cannot be precluded, but requires confirmation. Copyright © 2012 Society of Chemical Industry     

单宁基酚胺型螯合树脂的制备及对Cr(VI)的吸附

杨梅单宁先与氯化亚砜反应制得氯代单宁,再与聚乙烯亚胺交联合成单宁基酚胺型螯合树脂。通过FTIR、SEM、EDS和XPS对单宁基酚胺型螯合树脂的结构进行表征,并考察了螯合树脂对Cr(VI)的吸附性能。在单宁的分子结构侧链引入氨基,能有效改善单宁基螯合树脂对Cr(VI)的吸附性能,螯合树脂对Cr(VI)的吸附主要为还原吸附,铬主要以Cr(III)的形式吸附到树脂上;在温度为318 K、pH为2.0、Cr(VI)初始质量浓度为500 mg/L时,单宁基酚胺型螯合树脂对Cr(VI)的最大吸附量达到364.46 mg/g;当Cr(VI)初始质量浓度低于20 mg/L时,树脂对铬的吸附率达到95%以上;单宁基酚胺型螯合树脂对Cr(VI)的吸附过程符合Langmuir等温吸附模型和准二级吸附动力学方程。该树脂在含铬废水处理方面具有潜在的应用前景。     

Supercritical fluid extraction of wormwood (Artemisia absinthium L.)

The objective of the work was to optimize the extraction of wormwood oil by supercritical fluid extraction (SFE) of growth-controlled plant material. Different extraction conditions, two growth techniques and various crops were tested and the evolution of the extracted oil composition was screened chromatographically. A comparison with conventional techniques such as hydrodistillation (HD) or organic solvent extraction (OSE) was also presented. Particularly, six CO₂ densities ranging from 285.0 kg/m³ to 819.5 kg/m³ were studied in the range of 9.0-18.0 MPa and 40-50 °C. A systematic study was carried out with plant material from 2005, while SFE of 2006, 2008 and aeroponically grown crops was performed for comparative purposes. The effect of ethanol as a modifier of the supercritical fluid extraction was also studied. The major compounds found in the SFE extracts as well as in the HD essential oils were Z-epoxyocimene, chrysanthenol and chrysanthenyl acetate. A model based on mass transfer equations, the Sovová model, was successfully applied to correlate the experimental data.     

Extraction and identification of proanthocyanidins from grape seed (Vitis Vinifera) using supercritical carbon dioxide

In this study, supercritical carbon dioxide extraction of proantocyanidins (PRCs) was performed and the effect of different pressure, temperature and ethanol percentage was investigated. High performance liquid chromatography was used for the analysis of the compounds and it was found that the most effective parameter on the extraction was the amount of the ethanol percentage. Each compound was extracted from grape seeds at their maximum level when different parameters were used which was probably because of their different polarities. Gallic acid (GA), epigallocatechin (EGC) and epigallocatechingallate (EGCG) were extracted at their maximum level when the 300 bar 50 °C and 20% of ethanol was used. The maximum amount of catechin (CT) and epicatechin (ECT) were obtained when 300 bar 30 °C and 20% of ethanol was used for extraction, and 250 bar, 30 °C and 15% of ethanol was needed to extract highest amount of epicatechingallate (ECG).     

Kinetic model of solute aqueous extraction from Fennel (Foeniculum vulgare) treated by pulsed electric field, electrical discharges and ultrasonic irradiations

This work investigates the aqueous extraction from Fennel (Foeniculum vulgare) assisted by pulsed electric field (PEF), electrical discharges (ED) and ultrasound irradiations (UI). It aims the improvement of the solutes yield and the extraction kinetics at room temperature.Fennel gratings of size (1.5 × 0.75 × 30-50 mm³; width × height × length), were treated by PEF (intensity: 50-1200 V/cm and number of pulses: 50-1000), ED (voltage: 40 kV and number of discharges: 10-60) and ultrasound (intensity: 400 W/cm² and treatment duration: 10-350 min). The liquid-to-solid (weight/weight) ratio equal to 2. All tests were carried out at room temperature (20 °C), under stirring at 250 rpm. The extraction kinetics was modelled using a simplified two-exponential kinetic model, which corresponds to mass transfer in two stages (rapid washing and slow diffusion).The optimal parameters of PEF, ED and UI, giving the maximal juice yield, were determined and the effect of these three treatments on the mass transfer rate was studied.