| 1. |
- Andersson, J. M., et al.
(författare)
-
Pressurised hot water extraction with on-line particle formation by supercritical fluid technology
- 2012
-
Ingår i: Food Chemistry. - : Elsevier BV. - 1873-7072 .- 0308-8146. ; 134:4, s. 1724-1731
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, an on-line process for pressurised hot water extraction (PHWE) of antioxidants from plants as well as drying of the extract in one step by particle formation based on the use of supercritical carbon dioxide (SC-CO2) has been developed. This process has been called WEPO (R), water extraction and particle formation on-line. With this process, dried extracts from onion with the same composition of quercetin derivatives as non-dried extracts have been obtained as a fine powder with spherical particles from 250 nm to 4 mu m in diameter. The major compounds present in the extract were quercetin-3,4'-diglucoside, quercetin-4'-glucoside and quercetin. An auxiliary inert gas (hot N-2) was used to enhance the drying process. Parameters such as temperature (120 degrees C), SC-CO2 and N-2 pressures (80 and 12.5 bar, respectively) and flow rate of SC-CO2 (10 ml/min), have been settled by trial-and-error in order to achieve a fine and constant spray formation. Water content, size and morphology, antioxidant capacity and quercetin content of the particles were studied to evaluate the efficiency of the WEPO process. Results were compared with the ones from extracts obtained by continuous flow PHWE followed by freeze-drying. Results showed that both processes gave similar results in terms of antioxidant capacity, concentration of quercetin derivatives and water content, while only WEPO was able to produce defined spherical particles smaller than 4 mu m. (C) 2012 Elsevier Ltd. All rights reserved.
|
|
| 2. |
- Arapitsas, Panagiotis, et al.
(författare)
-
Characterisation of anthocyanins in red cabbage using high resolution liquid chromatography coupled with photodiode array detection and electrospray ionization-linear ion trap mass spectrometry.
- 2008
-
Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 109:1, s. 219-226
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this work was to analyse and tentatively identify anthocyanin species in red cabbage using HPLC/DAD-ESI/Qtrap MS. The extraction was realized by using a pressurized liquid technique and the separation of the pigments was achieved by a high resolution liquid chromatography system with a 1.8 mu m particles C-18 column. Photodiode array detection was employed to determine the UV/Vis spectral characteristic of the pigments. Electrospray ionization-linear ion trap mass spectrometry allowed the specific determination of the fragmentation patterns of the anthocyanins, by performing different ion scan modes. Twenty four anthocyanins were separated and identified, all having cyanidin as aglycon, represented as mono- and/or di-glycoside, and acylated, or not, with aromatic and aliphatic acids. Nine anthocyanins were identified for the first time in red cabbage.
|
|
| 3. |
- Ares, Ana M., et al.
(författare)
-
Fast determination of intact glucosinolates in broccoli leaf by pressurized liquid extraction and ultra high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry
- 2015
-
Ingår i: Food Research International. - : Elsevier BV. - 0963-9969. ; 76, s. 498-505
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigate for the first time the efficiency of an environmentally sustainable extraction technique (pressurized liquid extraction, PIE) in conjunction with a fast separation technique (ultra-high performance liquid chromatography, UHPLC) coupled to a selective mass spectrometry (MS) detector (quadrupole time-of-flight, qTOF) to extract, separate and quantify fifteen intact-glucosinolates (GLSs) in broccoli leaves. Firstly, we have developed and optimized by means of an experimental design an efficient extraction procedure based on PLE (using ethanol/water as a solvent), giving complete extraction within 15 min; meanwhile, the average analyte recoveries were between 85% and 96% in all cases. Chromatography was performed on a UHPLC BEH Shield RP181.7 mu m 110 angstrom (2.1 x 100 mm) analytical column with a mobile phase composed by formic add in water (0.5%, v/v) and formic acid in acetonitrile (0524 v/v) in gradient elution mode at 03 mL/min, resulted in baseline-separated peaks and a run time of 13 min. The method was fully validated in terms of selectivity, limits of detection (LOD) and quantification (LOQ), linearity, precision, and trueness; meanwhile a study of the matrix effect was also performed. A good selectivity, low LODs and LOQs, ranging from 2 to 26 mu g/g, wide linear ranges from LOQ to 2500 mu g/g, and satisfactory precision and trueness with relative standard deviation and relative error values lower than or equal to 9%, were obtained for the studied GLSs. Finally, the proposed method was successfully applied to the analysis of intact-GLSs in fifteen broccoli leaf samples from three different cultivars (Parthenon, Nubia, and Naxos). Nine intact-GLSs were detected in all the varieties, although in different concentrations, which ranged between 14 and 1136 mu g/g, depending on the broccoli cultivar. In addition, the highest total content of GLSs was found in broccoli leaf samples from Parthenon cultivar, being the Naxos cultivar the poorest in GLS content. This study demonstrates the efficiency of PLE as an environmentally sustainable alternative to extract intact-GLS from broccoli leaves, and that UHPLC-qTOE-MS allowed a rapid, selective and sensitive determination of intact-GLSs in this matrix. (C) 2015 Elsevier Ltd. All rights reserved.
|
|
| 4. |
- Bergvall, Ulrika A., et al.
(författare)
-
Anti-browsing effects of birch bark extract on fallow deer
- 2013
-
Ingår i: European Journal of Forest Research. - : Springer Science and Business Media LLC. - 1612-4669 .- 1612-4677. ; 132:5-6, s. 717-725
-
Tidskriftsartikel (refereegranskat)abstract
- A major problem within forest industry is unwanted browsing on seedlings from mammalian herbivores. The aim of this study was to evaluate the effects of birch bark extracts as repellents towards fallow deer. Birch bark was extracted in a conventional way with ethanol as solvent at ambient temperature and with a new method, liquid CO2 extraction. An analysis of the ethanol-extracted birch bark showed that it contained large amounts of terpenoids, of which the most abundant was betulin. In seven different treatment trials, we used 15 individually handled fallow deer. To investigate the binary taste preferences, birch bark extract was added to food and presented in two bowls in typical two-choice tests. We found that the amount of a food type consumed during a trial and the number of shifts between food bowls were dependent on the amount of the birch extract the food contained. Concentrations of above 1 % by dry weight of birch extract acted as a repellent. In addition, such concentrations produced shorter feeding bouts by a greater willingness to change bowls. Therefore, our conclusion is that birch bark extract acts as a repellent towards fallow deer and is therefore likely to act as a repellent against other deer species. In addition, we show that birch bark extract produced by the new and more environmentally sustainable method employing liquid CO2 mixed with ethanol has the same repellent effect as the traditional ethanol extraction.
|
|
| 5. |
|
|
| 6. |
- Co, Michelle, 1975-, et al.
(författare)
-
Degradation effects in the extraction of antioxidants from birch bark using water at elevated temperature and pressure
- 2012
-
Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 716, s. 40-48
-
Tidskriftsartikel (refereegranskat)abstract
- Experiments with birch bark samples have been carried to enable a distinction between extraction and degradation effects during pressurised hot water extraction. Two samples, E80 and El 80, contained birch bark extracts obtained after extraction at 80 and 180 degrees C for up to 45 min, respectively. Two other samples, P80 and P180, were only extracted for 5 min at the two temperatures and were thereafter filtered and hydrothermally treated at 80 and 180 degrees C, respectively. During the latter treatment, samples were collected at different times to assess the stability of the extracted compounds. An offline DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, as well as a high performance liquid chromatographic separation coupled to an electrochemical detector, were used to determine the antioxidant capacity of the processed samples. The results obtained with the different techniques were compared to assess the yield of the extraction and degradation processes. In addition, an online hyphenated system comprising high performance liquid chromatography coupled to diode-array; electrochemical; and tandem mass spectrometric detection (HPLC-DAD-ECD-MS/MS) was used to study the compositions of the extracts in more detail. The results for the samples processed at 80 degrees C showed that the extraction reached a steady-state already after 5 min, and that the extracted compounds were stable throughout the entire extraction process. Processing at 180 degrees C, on the other hand, gave rise to partly degraded extracts with a multitude of peaks in both the diode array and electrochemical detectors, and a higher antioxidant capacity compared to for the extracts obtained at 80 degrees C. It is concluded that HPLC-DAD-ECD is a more appropriate technique for the determination of antioxidants than the DPPH assay. The mass spectrometric results indicate that one of the extracted antioxidants, catechin, was isomerised to its diastereoisomers; (+)-catechin, (-)-catechin, (+)-epicatechin, and (-)-epicatechin.
|
|
| 7. |
- Co, Michelle, 1975-, et al.
(författare)
-
Extraction of Antioxidants from Spruce (Picea abies) Bark using Eco-Friendly Solvents
- 2012
-
Ingår i: Phytochemical Analysis. - : Wiley-Blackwell. - 0958-0344 .- 1099-1565. ; 23:1, s. 1-11
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction-Antioxidants are known to avert oxidation processes and they are found in trees and other plant materials. Tree bark is a major waste product from paper pulp industries; hence it is worthwhile to develop an extraction technique to extract the antioxidants.Objective- To develop a fast and environmentally sustainable extraction technique for the extraction of antioxidants from bark of spruce (Picea abies) and also to identify the extracted antioxidants that are abundant in spruce bark.Methodology- A screening experiment that involved three different techniques, was conducted to determine the best technique to extract antioxidants.The antioxidant capacity of the extracts was determined with DPPH (2,2-diphenyl-2’-picrylhydrazyl) assay. Pressurised fluid extraction (PFE) turned out to be the best technique and a response surface design was therefore utilised to optimise PFE. Furthermore, NMR and HPLC-DAD-MS/MS were applied to identify the extracted antioxidants.Results- PFE using water and ethanol as solvent at 160 and 180°C, respectively, gave extracts of the highest antioxidant capacity. Stilbene glucosides such as isorhapontin, piceid and astringin were identified in the extracts.Conclusion-The study has shown that PFE is a fast and environmentally sustainable technique, using water and ethanol as solvent for the extraction of antioxidants from spruce bark.
|
|
| 8. |
- Co, Michelle, 1975-
(författare)
-
Pressurised Fluid Extraction of Bioactive Species in Tree Barks : Analysis using Hyphenated Electrochemical Mass Spectrometric Detection
- 2010
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Analytical chemistry has developed throughout time to meet current needs. At present, the interest in biorefinery is growing, due to environmental awareness and the depletion of fossil resources. Biomass from agricultural and forestry industries has proven to be excellent raw material for different processes. Biorefinering valuable species such as bioactive species from biomass, without compromising the primary process of the biomass is highly desirable. Pressurised fluid extraction (PFE) using water and ethanol as a solvent was developed for extracting betulin from birch (Betula pendula) bark. Apart from betulin, stilbene glucosides such as astringin, isorhapontin and picied were also extracted from spruce (Picea abies) using PFE. PFE is an advanced technique that extracts at temperatures above the solvent’s atmospheric boiling point. The applied pressure in PFE is mainly to maintain the liquid state of the extraction solvent. Parameters such as type of solvent, temperature, and time affect the extraction selectivity and efficiency. Therefore it is necessary to comprehend these parameters in order to optimise extraction. The DPPH (1,1-diphenyl-2-picrylhydrazyl) assay was used to determine the antioxidant capacity and activity of the obtained bioactive species. The results showed high antioxidant capacity in bioactive species that were extracted at an elevated temperature, 180°C. Extraction and degradation occur simultaneously during the extraction. Hence, it is crucial to separate these two processes in order to obtain the actual value. An online hyphenated system of chromatographic separation electrochemical mass spectrometric detection was developed (LC-DAD-ECD-MS/MS). The electrochemical detector facilitates real-time monitoring of the antioxidant capacity and activity of each antioxidant and its oxidation products. This developed LC-DAD-ECD-MS/MS method enabled rapid screening of antioxidants and created a fingerprint map for their oxidation products. Characterisation and molecular elucidation of bioactive species were also performed. Degradation of bioactive species was investigated with the said online system and birch bark extract was compared with birch bark extracts that were hydrothermally treated. The obtained results showed some degradation of antioxidants at 180°C. In summary, the aim of this thesis was to develop analytical methods integrated with sustainable chemistry for extraction of bioactive species in biomass from the forestry industry. A novel online system using selective and sensitive detectors such as diode-array, electrochemical, and tandem mass spectrometry was developed to rapidly determine the antioxidant capacity and activity of antioxidants. Furthermore, tandem mass spectrometry enables identification of unknown bioactive species without the need of reference samples.
|
|
| 9. |
- Co, Michelle, et al.
(författare)
-
Pressurized liquid extraction of betulin and antioxidants from birch bark
- 2009
-
Ingår i: Green Chemistry. - : The Royal Society of Chemistry. - 1463-9262 .- 1463-9270. ; 11:5, s. 668-674
-
Tidskriftsartikel (refereegranskat)abstract
- Pressurized hot (subcritical) water and ethanol were used to extract betulin and antioxidants from birch bark. Betulin was found to be the major compound (around 26% (w/w)), which was able to be extracted with ethanol (120 degrees C, 50 bar, 15 minutes) but not with water at any of the temperatures tested (40-180 degrees C, 50 bar). The obtained extraction result for betulin is supported by theoretical solvation parameter calculations. Furthermore, high antioxidant activity of the extract was obtained using both ethanol and water as solvent. The antioxidant activity, as determined by a DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, was found to be highest for the water extract of finely ground bark and it markedly increased with elevated extraction temperatures (90-180 degrees C). To elucidate if this was due to increased extraction efficiency or chemical reactions, a set of experiments was performed in which the samples were pre-treated with water at different temperatures before extraction. Results from liquid chromatography showed some differences in molecular composition between samples pre-treated at ambient and 180 degrees C, respectively. However, more detailed studies have to be performed to distinguish between hot-water extraction and reaction kinetics.
|
|
| 10. |
- Fridén, Mikael E, 1984-, et al.
(författare)
-
Evaluation and analysis of environmentally sustainable methodologies for extraction of betulin from birch bark with a focus on industrial feasibility
- 2016
-
Ingår i: Green Chemistry. - : Royal Society of Chemistry (RSC). - 1463-9262 .- 1463-9270. ; 18:2, s. 516-523
-
Tidskriftsartikel (refereegranskat)abstract
- Betulin from birch bark was extracted using two principally different extraction methodologies - classical Reflux Boiling (RB) and Pressurized Liquid Extraction (PLE). The extraction methods were analyzed based on both recovery and purity as well as for RB industrial feasibility. The purity and recovery for the different extraction methods were analyzed using High Performance Liquid Chromatography (HPLC) coupled with three different detection principles: Diode Array Detection (DAD), Mass Spectrometry (MS) and Charged Aerosol Detection (CAD). The chromatographic purity was determined by all detections whereas the DAD was used also for complementary gravimetric calculations of the purity of the extracts. The MS detection (in MS and MS/MS modes) was mainly used to characterize the impurities. Two steps to increase the purity of RB extracts were evaluated - pre-boiling the bark in water and precipitation by adding water to the extract. Finally, the methods were compared in terms of amounts of betulin produced and solvent consumed. The RB method including a precipitation step produced the highest purity of betulin. However, results indicate that PLE using three cycles with the precipitation step gives similar purities as for RB. The PLE method produced up to 1.6 times higher amount of extract compared to the RB method. However, the solvent consumption (liter solvent per gram product) for PLE was around 4.5 times higher as compared to the classical RB. PLE performed with only one extraction cycle gave results more similar to RB with 1.2 times higher yield and 1.4 times higher solvent consumption. The RB process was investigated on an industrial scale using a model approach and several important key-factors could be identified. The most energy demanding step was the recycling of extraction solvent which motivates that solvent consumption should be kept low and calculations show a great putative energy reduction by decreasing the ethanol concentration used in the RB process to lower than 90%.
|
|
