Purification of Anthocyanins from Extracts of Red Raspberry Using Macroporous Resin

Selective separation of chlorophyll-a using recyclable hybrids based on Zn-MOF@cellulosic fibers

Chlorophyll-a as pigments, exist in the green organelles for plants that act in photosynthesis. Different studies were considered with demonstration of an effective separation technique of Chlorophyll-a without decomposition; however, the reported methods were disadvantageous with expensiveness and low quantum yield. The current work uniquely represents an investigative method for the separation of Chlorophyll-a from spinach extract using cellulosic hybrids based on ZIF-8 @cellulosic fibers (Zn-zeolitic imidazolate frameworks@cellulosic fibers) as a cost effective and recyclable absorbents. To obtain hybrids, ZIF-8 was in-situ prepared over the cellulosic fibers (bamboo, modal and cotton). The untreated and treated fibers were well characterized via FTIR, SEM, EDX, XRD, in order to approve the successive impregnation of ZIF-8. Whereas, the microscopic images showed that, microcrystalline ZIF-8 rods with length of 1.3-4.4 µm were grown over the cellulosic fibers. The obtained hybrids and the untreated fibers were exploited in the separation of Chlorophyll-a via the adsorption/desorption process. The chlorophyll-adsorption was followed Langmuir isotherm and pseudo-second order model. The Langmuir maximum capacities of Chlorophyll-a onto hybrids were followed the order of ZIF-8@cotton (583.6 mg/g) > ZIF-8@modal (561.3 mg/g) > ZIF-8@bamboo (528.7 mg/g). After incorporation of ZIF-8, the maximum adsorption capacities of cellulosic fibers were enhanced by 1.4-1.9 times. Adsorption of chlorophyll onto the applied hybrids was lowered by 27-28%, after five repetitive washing cycles. The data summarized that; chlorophyll was effectively separated by the synthesized ZIF-8@cellulosic fibers hybrids, whereas, the prepared hybrids showed good reusability for application on wider scaled purposes.

Extraction and purification of anthocyanins from Peristrophe bivalvis (L.) Merr. leaf (Acanthaceae) using aqueous two-phase systems

Peristrophe bivalvis (L.) Merr. (Acanthaceae) is a Vietnamese herb that is rich in anthocyanin, a natural colorant. However, the common extraction methods for this pigment often accompany with the presence of contaminated compounds. This study, therefore, focused on applying the aqueous two-phase system (ATPS), a green method for extracting and purifying anthocyanin in the leaf extract. The obtained results revealed that an ATPS composing from ethanol and ammonium sulfate with the concentrations of 32.5% and 25%, respectively, can recover 80% anthocyanin in leaf while eliminating 80% contaminated nitrogen compounds. Besides, the shelf-life of pigment in the purified extract was also elongated significantly in comparison with that in the crude extract.

Antioxidant, cytotoxic, and antibacterial activities of Clitoria ternatea flower extracts and anthocyanin-rich fraction

Clitoria ternatea flower is a traditional medicinal herb that has been used as a natural food colourant. As there are limited studies on investigating the bioactivities of the anthocyanin-rich fraction of Clitoria ternatea flower, this study aimed to determine an efficient column chromatography method to obtain the anthocyanin-rich fraction from this flower and characterise its composition, antioxidant, antibacterial, and cytotoxic activities. Amberlite XAD-16 column chromatography was more efficient in enriching the total anthocyanin content (TAC) of the fraction with the highest TAC to total phenolic content (TPC) ratio of 1:6 than that using C18-OPN. A total of 11 ternatin anthocyanins were characterised in the anthocyanin-rich fraction by LC–MS analysis. The antioxidant activity of the anthocyanin-rich fraction was more potent in the chemical-based assay with an IC₅₀ value of 0.86 ± 0.07 mg/mL using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay than cellular antioxidant assay using RAW 264.7 macrophages. In vitro cytotoxicity assay using human embryonic kidney HEK-293 cell line showed the anthocyanin-rich fraction to be more toxic than the crude extracts. The anthocyanin-rich fraction had more potent antibacterial activity than the crude extracts against Bacillus cereus, Bacillus subtilis, and Escherichia coli. The anthocyanin-rich fraction of C. ternatea has the potential to be used and developed as a functional food ingredient or nutraceutical agent.

Anthocyanins in Different Food Matrices: Recent Updates on Extraction, Purification and Analysis Techniques

Anthocyanins (ANCs), a kind of natural pigments, are widely present in food substrates. Evidence has shown that ANCs can promote health in terms of anti-oxidation, anti-tumor, and anti-inflammation. However, the oxidative stability of ANCs limits accurate quantitation and analysis. Therefore, faster, more accurate, and highly sensitive extraction and determination methods are necessary for understanding the role of ANCs in medicine and food. This review presents an updated overview of pretreatment and detection techniques for ANCs in various food substrates since 2015. Liquid-liquid extraction and various green solvent extraction methods, such as accelerated solvents extraction, deep eutectic solvents extraction, ionic liquids extraction, and supercritical fluid extraction, are commonly used pretreatment methods for extraction and purification of ANCs. Liquid chromatography coupled with different detectors (tandem mass spectrometry and UV detectors) and spectrophotometry methods are some of the determination methods for ANC. This study has updated, compared, and discussed different pretreatment and analysis methods. Moreover, the advanced methods and development prospects in this field are comprehensively summarized, which can provide references for further utilization of ANCs.

Anthocyanins from purple sweet potato alleviate doxorubicin-induced cardiotoxicity in vitro and in vivo

In this study, anthocyanins were extracted and purified from purple sweet potato anthocyanins (PSPA) and the alleviative effect of PSPA on doxorubicin (DOX)-induced cardiotoxicity was investigated. High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) results showed that 10 kinds of substances were identified in PSPA and the PSPA was mainly composed of cyanidin (62.9%) and peonidin (21.46%). In in vitro experiments, PSPA reduced the excessive release of inflammatory factors (NO and TNF-α) induced by DOX and decreased the secretion of trimethylamine oxide (TMAO), lactic dehydrogenase (LDH), and creatine kinase (CK) caused by myocardial injury. In in vivo experiments, PSPA inhibited the release of NO and MDA levels in heart tissue. Meanwhile, mice treated with PSPA decreased the levels of LDH, CK, TNF-α, and TMAO in serum and heart tissue when compared with the DOX group. In addition, the histopathological results of the heart tissue also showed a protective effect of PSPA on the pathological changes in heart. These results provide a reference for the application of PSPA as a functional food to intervene in DOX-induced cardiotoxicity. PRACTICAL APPLICATIONS: The effects of anthocyanins from purple sweet potato anthocyanins (PSPA) on doxorubicin (DOX)-induced cardiotoxicity were investigated in vitro and in vivo. The results indicated that PSPA could significantly ameliorate DOX-induced heart failure. The obtained results could provide the potential application of PSPA as an alternative therapy for cardiotoxicity caused by DOX in the functional food industry.

Purification of Anthocyanins Derived from Black Kidney Bean (Phaseolus vulgaris L.) by a Simulated Moving Bed

Purification of anthocyanins derived from black kidney bean (Phaseolus vulgaris L.) by column chromatography and simulated moving bed (SMB) methods was investigated, and the anthocyanins of black kidney bean were identified. The SMB had advantages over column chromatography in processing efficiency, operation cost, and automation degree in contrast testing. The best SMB conditions resulted in purity and yield of black kidney bean anthocyanins of 24.61 ± 0.21% and 87.85 ± 0.32%, respectively. The half maximal inhibitory concentration (IC50) of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity and 2,2ʹ-azinobis-(3-ethylbenzthiazoline-6-sulphonate) radical (ABTS+∙) scavenging activity was 0.95 and 2.14 of refined anthocyanins, respectively, indicating strong antioxidant capacity. Three anthocyanins were detected and identified by UPLC-Triple-TOF/MS from black kidney bean skins: delphinidin-3-O-glucoside, petunidin-3-O-glucoside, and malvidin-3-O-glucoside. The experimental results suggested that SMB may help promote industrialization and purification of anthocyanins from colored kidney beans as well as from other plant materials.

A facile macroporous resin-based method for separation of yellow and orange Monascus pigments

The yellow Monascus pigments (YMPs) named monascin and ankaflavin and the orange Monascus pigments (OMPs) named rubropunctatin and monascorubrin are two groups of bioactive components in a mixture state in the Monascus fermented products. In order to separate these two groups of bioactive pigments, a facile macroporous resin-based method was developed. The weak-polar resin CAD-40 was selected from the seven tested macroporous resins as it revealed better properties for the adsorption and desorption of the YMPs and OMPs. Then, CAD-40 resin was used for column-chromatographic separation. After eluted by 4 bed volumes of ethanol, the yellow group (monascin and ankaflavin) and the orange group (rubropunctatin and monascorubrin) were successfully separated and purified, with an increased content from 49.3% and 44.2% in the crude pigment extract to 85.2% and 83.0% in the final products, respectively. This method would be helpful for the large-scale separation and purification of Monascus pigment products with specific bioactivity.

Rheological and technological characterization of red rice modified starch and jaboticaba peel powder mixtures

Properties of modified starch and its interaction with functional raw materials are of great interest to the food industry. Thus, this study aimed to evaluate the rheological and technological characterization of starches modified by the action of the enzymes α-amylase and amyloglucosidase and their mixtures with jaboticaba peel powder. The parameters of firmness, gumminess, and final viscosity of starches paste increased, and the tendency to setback was reduced with the addition of jaboticaba peel powder. Starches and mixtures presented shear-thinning behavior. The addition of jaboticaba peel powder to starches increased water, oil, and milk absorption capacity, while syneresis remained stable over the storage period. The addition of jaboticaba peel powder had a positive effect on native and modified starches' rheological and technological properties, qualifying it as an alternative for developing new functional food products.

Adsorption of Anthocyanins by Cation and Anion Exchange Resins with Aromatic and Aliphatic Polymer Matrices

This study examines the mechanisms of adsorption of anthocyanins from model aqueous solutions at pH values of 3, 6, and 9 by ion-exchange resins making the main component of heterogeneous ion-exchange membranes. This is the first report demonstrating that the pH of the internal solution of a KU-2-8 aromatic cation-exchange resin is 2-3 units lower than the pH of the external bathing anthocyanin-containing solution, and the pH of the internal solution of some anion-exchange resins with an aromatic (AV-17-8, AV-17-2P) or aliphatic (EDE-10P) matrix is 2-4 units higher than the pH of the external solution. This pH shift is caused by the Donnan exclusion of hydroxyl ions (in the KU-2-8 resin) or protons (in the AV-17-8, AV-17-2P, and EDE-10P resins). The most significant pH shift is observed for the EDE-10P resin, which has the highest ion-exchange capacity causing the highest Donnan exclusion. Due to the pH shift, the electric charge of anthocyanin inside an ion-exchange resin differs from its charge in the external solution. At pH 6, the external solution contains uncharged anthocyanin molecules. However, in the AV-17-8 and AV-17-2P resins, the anthocyanins are present as singly charged anions, while in the EDE-10P resin, they are in the form of doubly charged anions. Due to the electrostatic interactions of these anions with the positively charged fixed groups of anion-exchange resins, the adsorption capacities of AV-17-8, AV-17-2P, and EDE-10P were higher than expected. It was established that the electrostatic interactions of anthocyanins with the charged fixed groups increase the adsorption capacity of the aromatic resin by a factor of 1.8-2.5 compared to the adsorption caused by the π-π (stacking) interactions. These results provide new insights into the fouling mechanism of ion-exchange materials by polyphenols; they can help develop strategies for membrane cleaning and for extracting anthocyanins from juices and wine using ion-exchange resins and membranes.

Ultrasonic-assisted modifications of macroporous resin to improve anthocyanin purification from a Pyrus communis var. Starkrimson extract

The present study presents an attempt to modify the surface properties of macroporous resins (MRs) in order to improve anthocyanin adsorption and desorption from Pyrus communis var Starkrimson fruit peel extract. A number of MRs were tested to optimise the ultrasonic-assisted adsorption (UAA) conditions; including ultrasonic power (100-400 W), resin-to-extract ratio (1-3 g/50 mL) and temperature (20-40 °C). Similarly, varying ultrasonic-assisted desorption (UAD) conditions were optimised; including ultrasonic power (200-600 W), resin-to-solvent ratio (1-4 g/50 mL), ethanol concentration (60-90% v/v) and temperature (20-40 °C). The Amberlyst 15 (H) cationic resin was found to be superior to the other tested resins. The maximum adsorption capacity (659 µg/g) of cyanidin 3-galactoside (Cy 3-gal) was achieved under the optimised UAA conditions (400 W, 20 °C and 1 g/50 mL), while 616 µg/g of Cy 3-gal was recovered under the optimised UAD conditions (582 W, 1 g/50 mL, 60% and 20 °C). Moreover, titratable-acid and total-sugar contents were found to be significantly lower under UAA than under conventional-assisted adsorption (CAA). ANOVA revealed that process factors had significant effects on the Cy 3-gal purification, as depicted by their linear, quadratic and interactive effects. While anthocyanin adsorption was found to be significantly improved at lower ultrasonic power, higher power promoted the desorption process. Adsorption under optimized UAA conditions followed pseudo second-order kinetics and multilayer adsorption (Freundlich isotherm) onto the Amberlyst 15 (H) resin surface was observed. The particle-size distribution curve and scanning electron microscopic images also revealed higher resin-surface roughness, peeling and the appearance of pores on the surface under ultrasonication.This is the first study to use ultrasonication to modify a cationic exchange resin for the improvement of Cy 3-gal purification from a fruit extract. This study can recommend the use of ultrasonication as a low-cost green technique that can improve macroporous resin characteristics for better purification of compounds from an extract.

An Efficient Strategy Based on Liquid–Liquid Extraction With Acid Condition and HSCCC for Rapid Enrichment and Preparative Separation of Three Caffeoylquinic Acid Isomers From Mulberry Leaves

Morus alba L. is a medicinal plant that contains a high amount of caffeoylquinic acids such as 3-caffeoylquinic acid (3-CQA), 5-caffeoylquinic acid (5-CQA) and 4-caffeoylquinic acid (4-CQA). This study aimed to establish a fast and efficient method for separating caffeoylquinic acids from mulberry leaves by using high-speed countercurrent chromatography coupled with macroporous resin. D101 resin showed better adsorption and desorption capacity for three caffeoylquinic acids among six macroporous resin adsorbents. The contents of 3-CQA, 5-CQA and 4-CQA reached for 4.77%, 18.95% and 9.84% through one cycle of D101 resin, which were 3.13-fold, 4.57-fold and 4.78-fold more than those in crude extracts, respectively. With a two-phase solvent system of ethyl acetate-water (1:1, V/V), >93% purity of target compounds were obtained in one cycle during 150 min with the recovery yields of 80.59%, 99.56% and 94.21% for 3-CQA, 5-CQA and 4-CQA, respectively. The structural identification of target compounds was carried out by ESI-MS, 1H NMR and 13C NMR spectra. The present result represented an easy and efficient separation strategy for the utilization of mulberry resource.

Bilberry anthocyanin extract promotes intestinal barrier function and inhibits digestive enzyme activity by regulating the gut microbiota in aging rats

This study was aimed at understanding potential mechanisms regarding bilberry anthocyanin extract consumption and healthy aging and the effects on intestinal barrier function and digestive enzyme activity, through regulating the gut microbiota in aging rats. Medium-dose bilberry anthocyanin extract consumption (20 mg per kg bw per day) was the optimum amount to regulate the intestinal function of aging rats. After consumption, bacteria beneficial to the intestine (Aspergillus oryzae, Lactobacillus, Bacteroides, Clostridiaceae-1, the Bacteroidales-S24-7-group and the Lachnospiraceae_NK4A136_group) were induced to grow, and harmful bacteria (Verrucomicrobia and Euryarchaeota) were inhibited. However, high-dose bilberry anthocyanin extract consumption altered some intestinally beneficial bacteria in an adverse way. There was a correlation between changes in bacterial composition and changes in short-chain fatty acids and the intestinal mucosal barrier. Bilberry anthocyanin extract consumption also decreased the activity of digestive enzymes. Our results suggest that bilberry anthocyanin extract consumption is a potential approach for assisting healthy aging.

Modeling of the Adsorption/Desorption Characteristics and Properties of Anthocyanins from Extruded Red Cabbage Juice by Macroporous Adsorbent Resin

The adsorption/desorption characteristics, modeling and properties of anthocyanins from extruded red cabbage juice by macroporous resins were investigated. The static adsorption and desorption capacities of red cabbage anthocyanins on five macroporous resins were measured and compared. The X-5 resin showed the best capacities and was selected for the adsorption kinetics, isotherms and elution studies. The pseudo-second-order kinetic model and Langmuir isotherm model were used to describe the adsorption process and mechanism. Dynamic adsorption and desorption tests were performed on a fixed-bed column, and the loading and eluent conditions were optimized. The purity of anthocyanins in freeze-dried purified powder by the resin adsorption process is 21.3 ± 0.9 wt % and shows better stability in the air than the unpurified one. Finally, the antioxidant activity and color properties including color density, color intensity, color tonality and degradation index of the purified powders were measured.