An on-line method for pressurized hot water extraction and enzymatic hydrolysis of quercetin glucosides from onions.
Lindahl, Sofia LU ; Liu, Jiayin LU ; Khan, Sami LU ; Nordberg Karlsson, Eva LU
and Turner, Charlotta
LU
(2013)
In Analytica Chimica Acta
785.
p.50-59
- Abstract
- A novel environmentally sound continuous-flow hot water extraction and enzymatic hydrolysis method for determination of quercetin in onion raw materials was successfully constructed using a stepwise optimization approach. In the first step, enzymatic hydrolysis of quercetin-3,4'-diglucoside to quercetin was optimized using a three level central composite design considering temperature (75-95°C), pH (3-6) and volume concentration of ethanol (5-15%). The enzyme used was a thermostable β-glucosidase variant (termed TnBgl1A_N221S/P342L) covalently immobilized on either of two acrylic support-materials (Eupergit(®) C 250L or monolithic cryogel). Optimal reaction conditions were irrespective of support 84°C, 5% ethanol and pH 5.5, and at these... (More)
- A novel environmentally sound continuous-flow hot water extraction and enzymatic hydrolysis method for determination of quercetin in onion raw materials was successfully constructed using a stepwise optimization approach. In the first step, enzymatic hydrolysis of quercetin-3,4'-diglucoside to quercetin was optimized using a three level central composite design considering temperature (75-95°C), pH (3-6) and volume concentration of ethanol (5-15%). The enzyme used was a thermostable β-glucosidase variant (termed TnBgl1A_N221S/P342L) covalently immobilized on either of two acrylic support-materials (Eupergit(®) C 250L or monolithic cryogel). Optimal reaction conditions were irrespective of support 84°C, 5% ethanol and pH 5.5, and at these conditions, no significant loss of enzyme activity was observed during 72h of use. In a second step, hot water extractions from chopped yellow onions, run at the optimal temperature for hydrolysis, were optimized in a two level design with respect to pH (2.6 and 5.5), ethanol concentration (0 and 5%) and flow rate (1 and 3mLmin(-1)) Obtained results showed that the total quercetin extraction yield was 1.7 times higher using a flow rate of 3mLmin(-1) (extraction time 90min), compared to a flow rate of 1mLmin(-1) (extraction time 240min). Presence of 5% ethanol was favorable for the extraction yield, while a further decrease in pH was not, not even for the extraction step alone. Finally, the complete continuous flow method (84°C, 5% ethanol, pH 5.5, 3mLmin(-1)) was used to extract quercetin from yellow, red and shallot onions and resulted in higher or similar yield (e.g. 8.4±0.7μmolg(-1) fresh weight yellow onion) compared to a conventional batch extraction method using methanol as extraction solvent. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/3913416
- author
- Lindahl, Sofia
LU
; Liu, Jiayin
LU
; Khan, Sami
LU
; Nordberg Karlsson, Eva
LU
and Turner, Charlotta
LU
- organization
- publishing date
- 2013
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Analytica Chimica Acta
- volume
- 785
- pages
- 50 - 59
- publisher
- Elsevier
- external identifiers
-
- wos:000320851400007
- pmid:23764443
- scopus:84878989247
- ISSN
- 1873-4324
- DOI
- 10.1016/j.aca.2013.04.031
- language
- English
- LU publication?
- yes
- id
- 12c72e62-d206-4e4a-851c-dbdea440ecd2 (old id 3913416)
- date added to LUP
- 2016-04-01 09:54:20
- date last changed
- 2024-02-20 23:26:16
@article{12c72e62-d206-4e4a-851c-dbdea440ecd2,
abstract = {{A novel environmentally sound continuous-flow hot water extraction and enzymatic hydrolysis method for determination of quercetin in onion raw materials was successfully constructed using a stepwise optimization approach. In the first step, enzymatic hydrolysis of quercetin-3,4'-diglucoside to quercetin was optimized using a three level central composite design considering temperature (75-95°C), pH (3-6) and volume concentration of ethanol (5-15%). The enzyme used was a thermostable β-glucosidase variant (termed TnBgl1A_N221S/P342L) covalently immobilized on either of two acrylic support-materials (Eupergit(®) C 250L or monolithic cryogel). Optimal reaction conditions were irrespective of support 84°C, 5% ethanol and pH 5.5, and at these conditions, no significant loss of enzyme activity was observed during 72h of use. In a second step, hot water extractions from chopped yellow onions, run at the optimal temperature for hydrolysis, were optimized in a two level design with respect to pH (2.6 and 5.5), ethanol concentration (0 and 5%) and flow rate (1 and 3mLmin(-1)) Obtained results showed that the total quercetin extraction yield was 1.7 times higher using a flow rate of 3mLmin(-1) (extraction time 90min), compared to a flow rate of 1mLmin(-1) (extraction time 240min). Presence of 5% ethanol was favorable for the extraction yield, while a further decrease in pH was not, not even for the extraction step alone. Finally, the complete continuous flow method (84°C, 5% ethanol, pH 5.5, 3mLmin(-1)) was used to extract quercetin from yellow, red and shallot onions and resulted in higher or similar yield (e.g. 8.4±0.7μmolg(-1) fresh weight yellow onion) compared to a conventional batch extraction method using methanol as extraction solvent.}},
author = {{Lindahl, Sofia and Liu, Jiayin and Khan, Sami and Nordberg Karlsson, Eva and Turner, Charlotta}},
issn = {{1873-4324}},
language = {{eng}},
pages = {{50--59}},
publisher = {{Elsevier}},
series = {{Analytica Chimica Acta}},
title = {{An on-line method for pressurized hot water extraction and enzymatic hydrolysis of quercetin glucosides from onions.}},
url = {{http://dx.doi.org/10.1016/j.aca.2013.04.031}},
doi = {{10.1016/j.aca.2013.04.031}},
volume = {{785}},
year = {{2013}},
}