Purification Of Phenolic Compounds Research Articles

Adsorption and desorption process for high recovery and purification of anthocyanins from (Clitoria ternatea L) using macroporous resins

The intense coloration of the petals of the butterfly bean flowers (Clitoria Ternatea L.) is attributed to high content of anthocyanins, which are considered as an antioxidant phytochemicals that have many health benefits. In this context, it is so important to implement a new method for the separation and purification of phenolic compounds. Therefore, the objective of this work was to evaluate the adsorption and desorption behavior of anthocyanins extracted from the petals of the butterfly bean flowers, using six different macroporous adsorption resins (XAD 2, XAD 4, XAD 7HP, DAX 8. XAD 1180 N and XAD 16), and to identify the best type of resin for anthocyains recovery from butterfly bean flowers extract. The XAD7HP and DAX8 resins showed high adsorption capacity, (248.55 ± 8.8 mg/g) and (228.84 ± 16.9 mg/g) at pH 5, and the highest recovery values for anthocyanins; (75.66 ± 1.1%) and (52.64 ± 1.2%), respectively. The Langmuir model described better the adsorption isotherm process on DAX 8, in turn, the experimental data of equilibrium were better fitted by Freundlich model for isotherm adsorption of anthocyanin on XAD7HP resin. The pseudo-second order model was the best to fit the experimental data of the adsorption kinetics at the different temperatures used. Both resins XAD 7HP and DAX 8 presented high recovery of anthocyanin, comparing with conventional extracted methods the purified anthocyanin using XAD 7HP and DAX 8 can be used as biological compounds with more purity for food and pharmaceutical applications.

Purification of Phenolic Compounds from Camellia polyodonta Flower: Composition Analysis, Antioxidant Property, and Hypolipidemic Activity In Vitro and In Vivo.

Camellia polyodonta flowers are rich sources of phenolics and less attention has been paid to their potential biological activity. This study aims to explore the crude extracts and resulting purified fractions (CPFP-I, II, III, and IV) through compositional analysis and antioxidant and hypolipidemic activities in vitro and in vivo. Among four fractions, CPFP-II contained the highest total phenolic content and flavonoid content, while CPFP-III exhibited the greatest total proanthocyanidin content. Among the 14 phenolic compounds, CPFP-II displayed the highest content of procyanidin B2, B4, and C1, whereas CPFP-III contained the highest amount of 1,2,3,6-tetragalloylglucose. The DPPH, ABTS, and FRAP assessments demonstrated a consistent trend: CPFP-II > CPFP-III > CPFP-I > CPFP-IV. In vivo experiments showed that that all four fractions significantly reduced lipid levels in hyperlipidemic C. elegans (p < 0.05), with CPFP-II exhibiting the most potent effect. Furthermore, CPFP-II effectively bound to bile acids and inhibited the enzymatic activity of pancreatic lipase in vitro. Consequently, CPFP-II should be prioritized as a promising fraction for further exploration and should provide substantial support for the feasibility of the C. polyodonta flower as a natural alternative.

Green Extraction Strategy Using Bio-Based Aqueous Biphasic Systems for Polyphenol Valorization from Grape By-Product.

Polyphenols are natural compounds with enhanced antioxidant properties. They are present in relatively high concentrations in fruit/vegetable by-products. Therefore, there is a need for the development of efficient and cost-effective methods for the separation and purification of these valuable compounds. Traditional extraction with organic solvents needs to be switched to novel methods that are more efficient, with reduced extraction times and low consumption of organic solvents. Aiming at developing sustainable processes for the separation and purification of phenolic compounds, we used three model compounds, namely resveratrol, quercetin, and gallic acid, to investigate ionic liquid-based aqueous biphasic systems (IL-ABSs) formed by cholinium-based IL in combination with polypropylene glycol with a molecular mass of 400 g/mol (PPG400). The ABS composition in the two-phase region was selected according to a previously determined phase diagram. Extraction studies indicated the preferential partition of resveratrol and quercetin toward the hydrophobic PPG-rich phase that is mainly dominated by its hydrophobic nature and the strong salting-out effect of ILs. On the other hand, due to its considerably hydrophilic nature, gallic acid preferentially migrates toward the IL phase. The achieved results from grape stem extract demonstrated high extraction efficiencies of cholinium dihydrogen phosphate (~99% for resveratrol for the PPG phase and 78% for gallic acid for the IL phase), with considerable selectivity, demonstrating promising outcomes for potential applications.

Separation process characteristics of phenolic compounds from organic purple‐fleshed sweet potatoes (Ipomoea batatas L.) leaves using macroporous resins

AbstractCurrent trends have been noticed in to study of unedible parts of food as sources of phytochemicals or as ingredients in order to develop new uses for discarded materials and to promote sustainability. This study aimed to evaluate the performance of six macroporous resins (XAD 16, XAD 7HP, XAD 2, XAD 4, DAX 8, and XAD 1180 N) in purification of phenolic compounds from organic purple‐fleshed sweet potatoes. Static adsorption and desorption showed that XAD16 and XAD7HP had the highest adsorption and desorption ratio and recovery yield. The process temperature did not affect the adsorption capacity of XAD16. However, XAD7HP showed higher adsorption capacity when performed at 30°C, compared with 40 and 50°C. The process of equilibrium adsorption isotherms for phenolics was better described using Freundlich isotherm model. Dynamic adsorption process on XAD7HP resin showed that phenolic compounds in the water extracts of leaves started to break through after 4.5 bed volumes of extract was loaded. The purification of phytochemicals using adsorption is an alternative to replace organic solvents and provide a safety process for industrial application.Practical ApplicationsRecently, phenolic compounds have been explored due to their significant biological and antioxidant properties; phenolic compounds are also related to decreasing the risk of cardiovascular diseases, cancer, oxidative stress, diabetes, fatness, cancer, and several degenerative diseases. In addition, there is the potential use of phenolic compounds such as anthocyanin as safe colorimetric pH indicators in innovative packaging due to the relationship between levels of pH and anthocyanin colors. Therefore, using advanced processing technologies, phenolic compound purification can be essential for many applications related to food safety, quality, nutrition, and food waste. Furthermore, purified phenolic compounds can be used as raw materials in the pharmaceutical area and food industries.

The Research Progress of Extraction, Purification and Analysis Methods of Phenolic Compounds from Blueberry: A Comprehensive Review.

Blueberry is the source of a variety of bioactive substances, including phenolic compounds, such as anthocyanins, pterostilbene, phenolic acids, etc. Several studies have revealed that polyphenols in blueberry have important bioactivities in maintaining health, such as antioxidant and anti-tumor activities, immune regulation, the prevention of chronic diseases, etc. Therefore, these phenolic compounds in blueberries have been widely used in the field of healthcare, and the extraction, isolation, and purification of phenolic compounds are the prerequisites for their utilization. It is imperative to systematically review the research progress and prospects of phenolic compounds present in blueberries. Herein, the latest progress in the extraction, purification, and analysis of phenolic compounds from blueberries is reviewed, which can in turn provide a foundation for further research and usage of blueberries.

Simultaneous extraction and preliminary purification of polyphenols from grape pomace using an aqueous two-phase system exposed to ultrasound irradiation: Process characterization and simulation.

In this study, an ultrasound-assisted aqueous two-phase (ATP) extraction method was used for the extraction and purification of phenolic compounds from grape pomace. The effect of acoustic energy densities (AED, 41.1, 63.5, 96.1, 111.2 W/L) and temperatures (20, 30, 40°C) on the yield of phenolics was investigated. An artificial neural network (ANN) was successfully used to correlate the extraction parameters with phenolic yield. Then, a diffusion model based on Fick's second law was used to model the mass transfer process during ultrasound-assisted ATP extraction and evaluate the effective diffusion coefficient of phenolics. The results revealed the increase in AED, and the temperature increased the effective diffusivity of phenolics. The HPLC analysis of anthocyanins and flavonols showed that ultrasound significantly increased the extraction yield of anthocyanins compared with the traditional method. High amounts of rutin and myricetin were recovered using the ATPS systems. Sugars were mainly distributed in the bottom phase, whereas phenolics were located in the top phase. Conclusively, ultrasound-assisted aqueous two-phase (ATP) extraction can be used as an effective method to achieve the simultaneous separation and preliminary purification of phenolics from grape pomace.

Salvia bowleyana Dunn root is a novel source of salvianolic acid B and displays antitumor effects against gastric cancer cells.

Salvianolic acid B (Sal-B) is widely used in China for the treatment of numerous diseases. Currently, Salvia miltiorrhiza Bunge is the main source of this compound, but Salvia bowleyana Dunn, a surrogate of S. miltiorrhiza Bge, may provide a novel source for obtaining more Sal-B. In the present study, a simple method for separation and purification of phenolic compounds from S. bowleyana Dunn roots was employed. Sal-B was subsequently purified and its inhibitory effect on the gastric cancer HGC-27 and AGS cell lines was investigated. Sal-B extracted from S. bowleyana Dunn displayed significant antitumor activity in proliferation and apoptosis assays. Overall, it was found that S. bowleyana Dunn has a higher Sal-B content than S. miltiorrhiza Bge and may be used as a novel source of this potential anti-gastric cancer compound.

Purification of phenolic compounds from genipap (&lt;i&gt;Genipa americana&lt;/i&gt; L.) extract by the ultrasound assisted ultrafiltration process

The aim of this study was to evaluate the potential of an integrated membrane process for purification of polyphenol and genipin components from genipap fruit extract. Optimal conditions for aqueous extraction of polyphenols from genipap fruit pulp were at 71°C for 49 min using a fruit pulp:water ratio of 1:3 (w w-1). Microfiltration with membranes of different pore sizes (0.22, 0.3 and 0.8 µm) resulted in a clarified permeate with similar physical-chemical properties, but the permeate flux through the 0.8 µm membrane was higher than through the other membranes. The sequential ultrafiltration process reduced even more total and soluble solids of the microfiltered extract. Purities of polyphenols and genipin were, respectively, 2.5 and 1.2 times greater in the permeate than in the feed stream. Application of ultrasound during the ultrafiltration increased the steady state permeate flux and the purities of polyphenols and genipin in the permeate stream. Results suggest application of microfiltration as a clarification step followed by the ultrasound assisted ultrafiltration to produce a purified genipap extract with high contents of polyphenols and genipin.

Semi-preparative isolation and purification of phenolic compounds from Achyrocline satureioides (Lam) D.C. by high-performance counter-current chromatography.

Phenolic compounds present in Achyrocline satureioides are known to have therapeutic benefits like antioxidant, anti-inflammatory, and antitumour properties. The main polyphenols present in the plant are quercetin (QCT), luteolin (LUT), 3-O-methylquercetin (3OMQ), and achyrobichalcone (ACB). However, the effective isolation and purification of these compounds from A. satureioides inflorescences are not an easy task. To develop an efficient high-performance counter-current chromatography (HPCCC) method for quick separation and purification of naturally occurring phenolic compounds from the extract of A. satureioides. A two-step HPCCC semi-preparative isolation method was developed using a solvent system composed of n-hexane/ethyl acetate/methanol/water (0.8:1.0:0.8:1.0) and dichloromethane/methanol/water (3.5:3.5:2.5). The HPCCC method was used to obtain two fractions. The first fraction (F1 ) contained high levels of ACB, among other constituents, while the second fraction (F2 ) contained mostly QCT, LUT, and 3OMQ. Besides the high ACB content, F1 contained three other flavonoid-aglycones (kaempferol, 97.3%; isokaempferide, 92.4%; and 3,3'-di-O-methylquercetin, 95.2%) identified by an ultra-performance liquid chromatography system coupled to a quadrupole time-of-flight with high-definition mass spectrometry (UPLC-QTOF/HDMS) and nuclear magnetic resonance (NMR) analysis. Purity levels of ACB, 3OMQ, QCT, and LUT were 98.0, 97.0, 97.5, and 90.2%, respectively. This is the first time that high purity ACB and six other flavonoids were obtained from A. satureioides inflorescences by HPCCC. These excellent results reveal the potential and versatility of HPCCC as a technique to produce different types of products from this plant species on a semi-preparative scale: enriched fractions, new metabolites, or high purity compounds.

Mathematical modeling and experimental coupling of solution layer crystallization on a vertically cold surface

Abstract Solution static layer crystallization is an effective technique that promises to overcome the challenges for the isolation, separation and purification of phenolic compounds that remained in treated Olive Mill Wastewater, after the application of a combination of other physicochemical separation processes. Crystallization in unstirred solutions is based on supercooling gradients of the different components in a liquid mixture. Due to the large number of experimental variables involved, a theoretical model was developed for the description of the system with the least possible variables. The mathematical model was compared with laboratory-scale experiments for the separation of a common phenolic compound, ferulic acid (FA), from aqueous solutions. Τhe transient profiles of the solution temperature and solute concentration were calculated numerically, solving a system of coupled partial differential equations, taking into consideration the mass and heat transfer and the crystallization kinetics. The determination of the crystal growth parameters was done by comparison of the experimental data with the values predicted by the model, for two different operational conditions. Knowledge of the solution temperature distribution allowed the determination of the solution saturation with respect to FA, which affects the crystal growth rate, the yield and the purity of the final product. The model can be further used to assist the optimization of the process design with respect to the product recovery and the duration of the process. Furthermore, despite the fact that the proposed methodology is validated at a preliminary level, focusing on the recovery of a single component from an aqueous solution, it could be served as the first step for the development of a more realistic model to predict the behaviour of a multi-component system.

Implementation of membrane filtration and melt crystallization for the effective treatment and valorization of olive mill wastewaters

Abstract The olive oil extraction process is of vital importance for the farmers at Mediterranean countries. However, olive oil production is directly associated with the co-production of large quantities of Olive Mill Wastewater (OMW), which are considered as wastes but at the same time can also be considered as byproducts enriched in high added value constituents, such as phenolic compounds. The idea in the present work is firstly to separate and isolate the low molecular size phenolic compounds from other organic compounds, of high molecular size, using a combination of membrane processes (Ultrafiltration, UF, Nanofiltration, NF, Reverse Osmosis, RO). Further exploitation of the RO concentrate with vacuum distillation and freeze drying leads to the recovery of solid mixtures of the phenolic compounds and sugars. The implementation of cooling crystallization as a next treatment process is suggested for the separation of the phenolic compounds from sugars based on their solubility differences as a function of temperature. Further isolation and purification of phenolic compounds, may be achieved using melting crystallization and each compound may be selectively crystallized at its respective freezing point. To test the purification system proposed here, model “synthetic solutions” were used. The model solutions were made up using compounds with different molecular sizes including phenolic compounds. In the present study, recovering and purification of phenolic compounds was examined by experiments in synthetic OMW, where sucrose and tyrosol were served as model compounds for sugars and phenolics respectively.

Optimisation of ultrasound-assisted extraction conditions for phenolic content and antioxidant activities of the alga Hormosira banksii using response surface methodology

This study aimed to optimise ultrasound-assisted extraction (UAE) conditions of the brown alga Hormosira banksii for total phenolic content (TPC) and antioxidant activities including total antioxidant capacity (ABTS), DPPH free radical scavenging capacity (DPPH) and ferric reducing antioxidant power (FRAP) using response surface methodology (RSM). Box–Behnken design was employed to assess the effect of ultrasonic temperature, time and power on the TPC and antioxidant activities of the extracts. The results showed that RSM was an accurate and reliable method in predicting TPC and antioxidant activities (ABTS, DPPH and FRAP) of the extracts with R 2 values of 0.97, 0.96, 0.92 and 0.94, respectively. The ultrasonic temperature and time had the significant impact on TPC and antioxidant capacities. The optimal UAE conditions for the maximal values of TPC and antioxidant activities were of 30 °C, 60 min and power 60%, or 150 W. The values of TPC and antioxidant activities (ABTS, DPPH, FRAP) achieved under these parameters were 23.12 (mg GAE g−1), 85.64 (mg TE g−1), 47.24 (mg TE g−1) and 12.56 (mg TE g−1), respectively. UAE was found to be more efficient in comparison to conventional extraction, with shorter time for extraction and higher of TPC level and antioxidant activities. Therefore, ultrasonic-assisted extraction using RSM is effective for extraction and further isolation and purification of phenolic compounds from H. banksii. In addition, this alga could be a potential rich source of natural antioxidants applied in food and pharmaceutical fields.

Isolation, purification, and identification of the main phenolic compounds from leaves of celery (Apium graveolens L. var. dulce Mill./Pers.).

We developed a simple and meaningful preparative method for the separation and purification of the main phenolic compounds from the leaves of celery (Apium graveolens L. var. dulce Mill./Pers.) and we established an accurate and specific analytical method for the identification of the main phenolic compounds from celery leaves. The crude extract from celery leaves was prefractioned by polyamide resin to enrich the phenolic compounds. They were then purified further by preparative high-performance liquid chromatography, and seven main phenolic compounds were obtained: including chlorogenic acid, luteolin 7-O-β-d-apiofuranosyl(1→2)-β-d-glucopyranoside, luteolin 7-O-β-d-glucopyranoside, apiin, chrysoeriol 7-O-β-d-apiofuranosyl(1→2)-β-d-glucopyranoside, luteolin 7-O-[β-d-apiofuranosyl(1→2)-(6''-O-malonyl)]-β-d-glucopyranoside, and apigenin 7-O-[β-d-apiofuranosyl(1→2)-(6''-O-malonyl)]-β-d-glucopyranoside. Their purities were measured by using high-performance liquid chromatography, and their chemical structures were confirmed using UV spectrophotometry, ultra high performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry, and NMR spectroscopy. Our studies indicate that preparative high-performance liquid chromatography combined with polyamide resin is a simple and meaningful preparative method for the separation and purification of phenolic compounds from the leaves of celery or other plants, and the use of UV spectrophotometry, ultra high performance liquid chromatography with quadrupole time-of-flight tandem mass spectrometry, and NMR spectroscopy is an accurate and specific analytical method for the identification of phenolic compounds.

Optimization of ultrasound-assisted extraction conditions for recovery of phenolic compounds and antioxidant capacity from banana (Musa cavendish) peel

A large quantity of banana peel is generated annually and is considered as waste with low value. This study aimed to optimize five extraction parameters; including ultrasonic temperature, time and power, as well as acetone concentration and sample to solvent ratio, for maximum recovery of phenolic compounds, flavonoids, proanthocyanidins and antioxidant properties from banana (Musa cavendish) peel using response surface methodology. The results showed that recovery yields of phenolic compounds, flavonoids, proanthocyanidins and antioxidant properties were affected by the extraction parameters; of which the acetone concentration had the greatest effect. Optimal extraction conditions were found to be at ultrasonic temperature of 30°C, ultrasonic time of 5 min, ultrasonic power of 150 W, sample to solvent ratio of 8:100 g/mL and acetone concentration of 60%. Under these optimal conditions, 23.49 mg of phenolic compounds, 39.46 mg of flavonoids and 13.11 mg of proanthocyanidins could be extracted from 1 g of banana (M. cavendish) peel. Practical applications Banana peel known as waste is generated in a big quantity with limited utilization. Therefore, it is necessary to utilize this by-product for adding value to food industry. This study was designed to establish a simple, effective extraction method for maximum recovery of phenolic compounds from banana peel. Findings from this study can be used for further isolation and purification of phenolic compounds from banana peel for subsequent application in nutraceutical and pharmaceutical industry.

Separation and purification of phenolic compounds from pomegranate juice by ultrafiltration and nanofiltration membranes

Pomegranate juice is well recognized for its nutritional and health benefits due to the presence of phenolic compounds, including anthocyanins, ellagic acid, phytoestrogenic flavonoids and tannins. Therefore, the demand for the production of functional foods containing bioactive compounds isolated from the juice has remarkably increased in the last decade.In this study ultrafiltration (UF) and nanofiltration (NF) flat-sheet membranes, with nominal molecular weight cut-off (MWCO) ranging from 1000 to 4000 Da, were tested to purify biologically active compounds from clarified pomegranate juice. The filtration process was evaluated in a crossflow pilot unit equipped with a Sepa CFII Membrane Cell System featuring an effective membrane area of 0.014 m2.A first screening was made in order to evaluate the performance of selected membranes in terms of productivity, fouling index and retention towards sugars, phenolic compounds and total antioxidant activity. Among these membranes the Desal GK membrane, with a MWCO of 2000 Da, displayed higher permeate fluxes, lower fouling index and a good separation efficiency of sugars from phenolic compounds in comparison with the other tested membranes. Therefore further experiments were addressed to evaluate the separation capability and the productivity of this membrane at different transmembrane pressure (TMP) values. Concentration/diafiltration experiments were also performed in order to obtain a retentate fraction enriched in phenolic compounds and a permeate stream mainly containing glucose and fructose.According to the proposed process the yields of polyphenols and anthocyanins in the retentate stream were of the order of 84.8% and 90.7%, respectively. The diafiltration step allowed to obtain a recovery efficiency in the permeate side for glucose and fructose up to 90% and 93%, respectively.

Phenolic content, antioxidant capacity and antimicrobial activity of leaf extracts from Pistacia atlantica

The aim of this study was to investigate the secondary metabolites related to Pistacia atlantica Desf as well as their biological activities. Results show that using ethanol as a solvent exhibited the highest content of total phenolics and flavonoids (68.23 mg GAE g−1 of DW and 44 mg RE g−1 of DW), followed by aqueous one (20.07 mg GAE g−1 of DW and 15 mg RE g−1 of DW). Good correlation (Data not shown) was obtained between the DPPH radical-scavenging activities and total phenolics contents. Many similarities were observed between the results of the DPPH (IC50 = 32 and 200 μg mL−1) and ABTS (IC50 = 42 and 300 μg mL−1) assays. All tested extracts contained phenolic compounds exhibited an antimicrobial effect against Gram-positive and Gram-negative bacteria. Further, researches for identification and purification of phenolic compounds are required.

Extraction and Purification of Phenolic Compounds from Lignocellulosic Biomass Assisted by Ionic Liquid, Polymeric Resins, and Supercritical CO2

A sustainable process of valorization of lignocellulosic biomass exploring the extraction and separation of high value phenolic compounds was developed. A scale-up pretreatment and fractionation process of biomass assisted by 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) ionic liquid (IL) was carried out at first. Thereafter, recovered IL formed a sample rich in phenolic compounds, which separation and purification was the main objective of the present work. The phenolic extraction from the recycled IL was studied employing adsorption methodology with specific polymeric resins. Amberlite XAD-7 and Silica C18 resins showed the highest extraction efficiency of phenolic compounds, while PVPP presented high selectivity toward tricin and a specific lignin fragment. Among the examined resins, Amberlite XAD-7 demonstrated the highest ratio of phenolic compounds extraction in comparison to IL. A residual quantity of IL was observed to remain in the extracted samples and this was overcome by applying supercrit...

Phenolic and flavonoid contents, antioxidant and antimicrobial activities of leaf extracts from ten Algerian Ficus carica L. varieties

ObjectiveTo determine the total phenolic and flavonoid contents, antioxidant and antimicrobial activities of methanolic leaf extracts of ten Algerian fig (Ficus carica L.) varieties (uniferous, biferous and caprifig tree). MethodsPhenolics were extracted by Soxhlet method and analyzed by the Folin–Ciocalteu colorimetric method. Flavonoids were determined by aluminum trichloride assay and the antioxidant capacity was determined by the 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay. The antimicrobial activity was studied with the disc diffusion method and a macrodilution broth method was used to determine the minimal inhibitory concentrations and minimal lethal concentrations. ResultsThe mean extract yield was 14.10% ± 0.66% (n = 10). Leaf extract of biferous followed by uniferous varieties had the highest total phenolic contents [(52.296 ± 5.232) and (48.973 ± 2.015) mg gallic acid equivalent/g of dry plant extract respectively], flavonoids [(14.388 ± 0.333) and (14.136 ± 1.082) mg quercetin equivalent/g of dry plant extract] and antioxidant capacity [IC50 (798.754 ± 108.590) and (825.004 ± 110.835) μg/mL]. Antioxidant capacity of fig leaves was significantly correlated with phenolic contents (r = 0.748). These extracts showed bactericidal activity and moderate antifungal activity, and the minimal inhibitory concentrations and minimal lethal concentrations were determined on Bacillus cereus and Staphylococcus aureus. ConclusionsAll tested extracts contain phenolic compounds and exhibited an antioxidant activity and an antimicrobial effect against Gram-positive and Gram-negative bacteria. Further researches on identification and purification of phenolic compounds are required.

Purification of artichoke polyphenols by using membrane filtration and polymeric resins

The present study aimed at evaluating the potential of an integrated process based on the use of membrane technology and adsorbent resins for the recovery, concentration and purification of phenolic compounds from artichoke wastewaters.In particular, artichoke wastewaters coming from the blanching step were pre-treated by ultrafiltration (UF) in order to remove suspended solids and macromolecular compounds. The UF permeate was submitted to a nanofiltration (NF) process producing a concentrated fraction enriched in phenolic and sugar compounds.Three different macroporous resins were tested through adsorption/desorption methods to produce purified phenolic fractions with high antioxidant activity. Samples produced in UF, NF and adsorption–desorption tests were assayed for phenolic composition (chlorogenic acid and apigenin 7-O-glucoside), sugar composition (fructose, glucose and sucrose) and antioxidant activity.Among the three different tested resins, the S 7968 offered the best performance in terms of adsorption/desorption ratio for chlorogenic acid, with a total adsorption/desorption yield (TADY) of 63.39%; for the apigenin 7-O-glucoside the S 7968 and the S 2328 resins showed a TADY in the range 68.31–78.45%.

Ultrasonic-assisted extraction and purification of phenolic compounds from sugarcane (Saccharum officinarum L.) rinds

In order to obtained highest extraction efficiency of phenolic compounds from the sugarcane rinds, a rapid extraction method based on ultrasound-assisted extraction technique using response surface methodology was investigated. Results showed that the optimal conditions were: solvent concentration 52.19 mL/100 mL, solid–liquid ratio 14.46 mL/g, ultrasonic temperature 61.54 °C and extraction time 31.30 min. The practical phenolic compounds extraction rate was 8.67 g/100 g DW, which was well matched with the predicted value of 8.82 g/100 g DW. Purified by macroporous resins adsorption or solvent extraction method, the total phenolic content of crude phenolic compounds extracts improved from 117.50 ± 13.00 to 302.50 ± 19.50 or 670.00 ± 17.00 mg/g, respectively. Gallic acid, chlorogenic acid and ferulic acid were identified as three main phenolic compounds in the phenolic compounds extract by HPLC analysis. Furthermore, TPC revealed good correlations with antioxidant activities. All of the results indicated that sugarcane rinds could be used as a good source of phenolic compounds with significant antioxidant activities.