The new green solvent ethyl lactate for the extraction of caffeine from vegetable matrices

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Química Física Aplicada. Fecha de lectura: 12-11-201

Pressurized liquid extraction of caffeine and catechins from green tea leaves using ethyl lactate, water and ethyl lactate + water mixtures

Ethyl-lactate (ethyl 2-hydroxy-propanoate) is a bio-renewable agrochemical solvent, very suitable and environmental benign for food applications, permitted by the U.S. Food and Drug Administration as pharmaceutical and food additive. In previous work, the authors demonstrated that pressurized liquid extraction (PLE) using ethyl lactate is a suitable alternative to remove caffeine from vegetal materials, e.g. green coffee beans and green tea leaves. The solubility of caffeine in ethyl lactate + water mixtures, at ambient temperature and pressure, exhibits a substantial increase for 60:40% ethyl lactate + water mixtures (data reported in this work). This result motivated the analysis of the effect of the ethyl lactate + water mixtures for the decaffeination target. Furthermore, in the case of green tea, the removal of caffeine reducing the extraction of catechins is desirable due to the adverse effects of caffeine on health, while catechins are high valued functional food ingredients. Thus, the use of ethyl lactate, water and ethyl lactate + water mixtures to attain this objective, i.e. the removal of caffeine form green tea leaves minimizing the extraction of catechins, was studied in this work. PLE was carried out in the temperature range 373-473 K and using different ethyl lactate + water mixtures. Extraction yield and recovery of key bioactive compounds (caffeine and monomeric catechins) were determined and compared, and the caffeine/catechins selectivity of the different solvents employed was estimated. High extraction yields were obtained with a mixture containing 25:75% of ethyl lactate + water, with values around 1.5 and 3.5 times higher than, respectively, the yields obtained with water and ethyl lactate. Yet, pure ethyl lactate proved to be the most selective solvent to extract caffeine from green tea leaves, minimizing the co-extraction of catechins, with a caffeine/catechins selectivity of 2.8 to 5.5 in the range 373-423 K. At these temperatures, with short extraction times (20 min) the recovery of caffeine is in the range 53-76% but only 26-36% of catechins present in the tea leaves were removedThis work was financed thanks to AGL2011-29857-C03-01 (Ministerio de Economía y Competitividad) and ALIBIRD, S2013/ABI-2728 (Comunidad de Madrid) project

Appraisal of the suitability of two-stage extraction process by combining compressed fluid technologies of polar lipid fractions from chia seed

Although triacylglycerols (TAG) are the major constituents of chia oil, it also contains minor lipid fractions that include phospholipids (PL) among other desirable components. Its amphiphilic character and excellent biocompatibility make PL appropriate for numerous applications with technological and nutritional significanceand potential health benefits. Given the difficulties entailed by the PL isolation, the efficiency for extracting such compounds using two environmental friendly techniques, pressurized liquid extraction (PLE) and supercritical fluid extraction (SFE) was evaluated. By using PLE with food-grade ethanol (EtOH), an oil recovery close to 100% was achieved in just 10 min. This oil extract was particularly rich in α-linolenic acid (ALA; 70%) as compared to the oil extracted by SFE (56%). In the case of SFE, the oil recovery was only 87% but increased to 99% when ethanol was added to CO2. However the use of co-solvent did not affect the fatty acid profile of the supercritical extracts or their TAG composition, where the high molecular weight TAG species were the predominant in all cases. With the exception of SFE without co-solvent, all methods applied were capable of extracting the PL fraction, although the content and distribution of the individual components present in this fraction differed markedly depending on the extraction conditions used. In this context, the use of a sequential extraction process, combining SFE and PLE was particularly interesting. The re-extraction by PLE of the chia cake, previously defatted by SFE, allowed to obtain an oil extract highly enriched in PLs, whose content exceeded 16% and with a higher PL species than the rest of the oil extractsThis study was supported in part by grants from the Spanish Ministry of Science, Innovation and Universities, Spain (AGL2017-87884 MINECO/AEI/FEDER, UE); by the Comunidad de Madrid through the B Programa de Actividades en Tecnologías, Spain (ALIBIRD-CM S2013/ABI-2728

Supercritical antisolvent particle precipitation and fractionation of rosemary (Rosmarinus officinalis L.) extracts

The simultaneous fractionation and precipitation of an ethanolic extract of rosemary (Rosmarinus officinalis L.) using supercritical carbon dioxide anti-solvent technique was studied, with the target of separate in two different fractions the key antioxidants of rosemary (i.e. rosmarinic acid, carnosic acid and carnosol). The effect of pressure and temperature on the fractionation process was investigated, together with the morphology and particle size distribution of the precipitates. Additionally, the chemical composition of the oleoresins were analyzed and reported. In the range of pressures (9-20 MPa) and temperatures (313-333 K) used in this work, the precipitates presented a 2-3 fold enrichment of rosmarinic acid, while carnosic acid and carnosol were concentrated (2-3 fold enrichment) in the oleoresin fractions. Furthermore, in general, oleoresins presented higher antioxidant activity than precipitates. Particles produced with a nozzle of diameter 101.6 μm were smaller and more spherical with increasing pressure (mean value 4-10 μm at 20 MPa) and decreasing temperatureThe authors gratefully acknowledge the financial support from Ministerio de Economía y Competitividad of Spain (Proyect AGL2016- 76736-C3-1-R). Somaris E. Quintana is grateful for the funding provided by Gobernación de Bolivar and Fundación Ceiba, Colombia, in the project “Bolívar Gana con Cienci

Fractionation and precipitation of licorice (Glycyrrhiza glabra L.) phytochemicals by supercritical antisolvent (SAS) technique

Supercritical anti-solvent precipitation (SAS) using carbon dioxide is a novel technique that can be used to produce powdered ingredients in small size particles, facilitating their incorporation into food matrices. In this work, the SAS precipitation of a licorice root ethanolic extract was studied. SAS assays were carried out at 15–20 MPa, 308.15 and 313.15 K, and two different concentrations (9.6 and 14.2 mg/ml) of the ethanolic licorice extract. In the range of conditions investigated, SAS pressure and temperature did not affect significantly the precipitation yield, but phytochemicals recovery was higher with the lower licorice extract concentration. Moreover, the fractionation of licorice bioactives (liquiritin, liquiritigenin, isoliquiritigenin, glabridin and glycyrrhizic acid) was assessed, together with the content of total phenolic compounds and antioxidant activity of the powders and oleoresin by-products obtained. In this respect, precipitates and oleoresins presented significant differences in the concentration of some licorice bioactives, and higher antioxidant activity was observed in precipitates. Additionally, significant effect of pressure, temperature and licorice extract concentration on the morphology and particle size of precipitates was observed, recovering smaller and more regular particles at 15–20 MPa, 313.15 K and 9.6 mg/ml licorice extract concentration, attaining satisfactory yield and antioxidant activityThe authors gratefully acknowledge the financial support from Ministerio de Economía y Competitividad of Spain (Projects AGL2017-89055-R and AGL2016-76736-C3-1-R). Somaris E. Quintana is grateful for the funding provided by Gobernación de Bolivar and Fundación Ceiba, Colombia, in the project “Bolívar Gana con Ciencia

Simultaneous supercritical fluid extraction of heather (Calluna vulgaris L.) and marigold (Calendula officinalis L.) and anti-inflammatory activity of the extracts

Heather (Calluna vulgaris L.) and marigold (Calendula officinalis L.) are two rich sources of bioactive pentacyclic triterpenes. The supercritical carbon dioxide (SCCO2) extraction of these two plants was explored at a pressure range of 25–50 MPa, 50 ºC, with or without fractionation, different extraction times (1.5–4.0 h) and using ethanol as a co-solvent (0 and 10% w/w). In order to determine potential synergisms, a combined extraction (heather + marigold 50:50) was also studied. In general, higher extraction yields were achieved when the co-solvent was added. Higher concentrations of total triterpenic acids were obtained in heather extracts, specially using ethanol. The co-solvent did not increase the terpene concentration in marigold extracts. For the combined extraction, an antagonist effect in the triterpene concentration was observed in absence of a co-solvent, whereas a synergistic effect was exhibited in its presence, especially for ursolic acid. In general, the extracts showed a certain anti-inflammatory effect, although a straight correlation with the analyzed triterpenic acids concentration was not exhibited. Moreover, the combined extraction exposed a similar anti-inflammatory activity in comparison with the individual plant extractsThe authors gratefully acknowledge the financial support from Ministerio de Economía y Competitividad of Spain (project AGL2013-48943-C2) and the Comunidad Autónoma de Madrid (ALIBIRD, project number S2013/ABI-2728

Effect of moisture and oil content in the supercritical CO2 defatting of hermetia illucens larvae

The supercritical defatting of H. illucens was scaled up at 450 bar and 60 ◦C from a 270 cm3 extraction cell to a vessel five times larger. Then, eight different H. illucens larvae batches, with vari able content of oil (16.80–29.17% w/w) and moisture (4.45–15.95% w/w) were defatted. The effect of these parameters on yield and oil composition was analyzed. The presence of moisture in the larvae batch, in the range of the values studied, had no negative effect on the oil recovery efficiency, which was mainly determined by the initial content of oil in the larvae samples. Furthermore, no differences were determined in the fatty acid profile of the oils recovered, which were rich in satu rated fatty acids, mainly lauric acid (ca. 50% w/w). Minor lipids, such as squalene and phytosterols, were determined in all the oil samples. The moisture content in the oils extracted was in the range of 0.118–1.706% w/w. Therefore, some samples exceeded the limits recommended for volatile matter in edible fats and oils (0.2%, including moisture). Yet, concerning the oil peroxide index, values were much lower than those corresponding to the oil extracted using hexan

Antioxidant and antimicrobial assessment of licorice supercritical extracts

Licorice (Glycyrrhiza glabra L.) is a plant used widely in herbal medicines due to their several biological potentials. The supercritical extraction of licorice roots was investigated to assess the antioxidant and antimicrobial activity of the extracts. Extraction conditions were pressures from 15 to 40 MPa, 313.15 and 333.15 K, and ethanol cosolvent in the range of 0 to 20% mass. In the case of high-pressure extractions using pure carbon dioxide (CO2) fractionation of the supercritical extract was accomplished in a two-cell decompression system. Fractionation was carried out with the aim to examine the potential separation of the antioxidant and antimicrobial licorice compounds and thus increase the bioactive properties of the fractions obtained in each separation cell. Main licorice bioactive compounds, liquiritin, liquiritigenin, glycyrrhizin, isoliquiritigenin and glabridin, were identified by HPLC and quantified using standards. Extracts obtained with supercritical CO2 and ethanol cosolvent contain the higher amounts of phenolic compounds and also the higher antioxidant activity but exhibit low or even no antimicrobial activity. Using pure CO2 at high pressure coupled with the on-line fractionation of the extract, two samples were obtained which showed, respectively, lower phenolic compounds content and good antimicrobial capacity (first fraction) and higher phenolic compounds content and antioxidant capacity (second fraction). Thus, the advantages of supercritical on-line fractionation are demonstrated in the extraction of Licorice rootsThe authors gratefully acknowledge the financial support from Ministerio de Economía y Competitividad of Spain (Projects AGL2016-76736-C3-1-R and AGL2015-64522-C2-R

Pressurized Liquid Extraction for the Production of Extracts with Antioxidant Activity from Borututu (Cochlospermum angolense Welw.)

Borututu (Cochlospermum angolense Welw.) roots have been described as a rich source of phenolic compounds. Despite the potential of this plant for the production of bioactive extracts, studies reported until now have been scarce, and they have been based on the use of inefficient conventional extraction techniques. In this study, pressurized liquid extraction (PLE) was investigated for the production of borututu root extracts. Different temperatures (50–200 °C) and solvents (water, ethanol, and 50% ethanol:water) were applied. The total phenolic compound (TPC) content, the main phenolic compounds and the in vitro antioxidant activity of the extracts were evaluated. The results were compared with those obtained by conventional decoction with water. The highest concentrations of TPC and antioxidant activity were obtained with 50% ethanol:water, followed by water. The extract obtained with 50% ethanol:water at 150 °C had a TPC concentration of 343.80 mg/g and presented the largest antioxidant activity (1488 and 4979 µmol Trolox/g extract, determined by DDPH and ABTS assay, respectively). These values were considerably higher than those obtained by conventional decoction. Ellagic acid, and ellagic and methyl ellagic acid glycosides were the main phenolic compounds found in the extracts. Therefore, was PLE demonstrated to be a selective and efficient technique to obtain extracts with high concentrations of phenolic compounds and high antioxidant activity form borututu root

Antioxidant, anti-Inflammatory, and antibacterial properties of an Achillea millefolium L. extract and Its fractions obtained by supercritical anti-solvent fractionation against Helicobacter pylori

The main objective of this work is to evaluate the potential utility of an Achillea millefolium extract (yarrow extract, YE) in the control of H. pylori infection. The supercritical anti-solvent fractionation (SAF) process of YE allowed the obtaining of two different fractions: yarrow’s precipitated fraction (YPF), enriched in most polar phenolic compounds (luteolin-7-O-glucoside, luteolin, and 3,5-dicaffeoylquinic acid), and yarrow’s separator fraction (YSF), enriched in monoterpenes and sesquiterpenes, mainly containing camphor, artemisia ketone, and borneol. YE was effective in reducing reactive oxygen species (ROS) production in human gastric AGS cells by 16% to 29%, depending on the H. pylori strain. YPF had the highest inhibitory activity (38–40%) for ROS production. YE modulated the inflammatory response in AGS gastric cells, decreasing IL-8 production by 53% to 64%. This IL-8 inhibition also showed a strain-dependent character. YPF and YSF exhibited similar behavior, reducing IL-8 production, suggesting that both phenolic compounds and essential oils could contribute to IL-8 inhibition. YSF showed the highest antibacterial activity against H. pylori (6.3–7.1 log CFU reduction, depending on the strain) and lower MIC (0.08 mg/mL). Results obtained have shown that YE and SAF fractions (YPF and YSF) were effective as antioxidant, anti-inflammatory, and antibacterial agents regardless of the H. pylori strain characteristic