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Investigating the effect of hot-wate...

Goundalkar, Mangesh J.

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Investigating the effect of hot-water extraction on phenolic constituents of selected hardwoods: A study aided by 2D NMR and GC-MS.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Investigating the effect of hot-water extraction on phenolic constituents of selected hardwoods: A study aided by 2D NMR and GC-MS./
Author:	Goundalkar, Mangesh J.
Description:	180 p.
Notes:	Source: Dissertation Abstracts International, Volume: 76-03(E), Section: B.
Contained By:	Dissertation Abstracts International76-03B(E).
Subject:	Agriculture, Wood Technology. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3645182
ISBN:	9781321338539

Investigating the effect of hot-water extraction on phenolic constituents of selected hardwoods: A study aided by 2D NMR and GC-MS.
Goundalkar, Mangesh J.

Investigating the effect of hot-water extraction on phenolic constituents of selected hardwoods: A study aided by 2D NMR and GC-MS. - 180 p.

Source: Dissertation Abstracts International, Volume: 76-03(E), Section: B.

Thesis (Ph.D.)--State University of New York College of Environmental Science and Forestry, 2014.

The SUNY-ESF biorefinery protocol begins with the pre-treatment of hardwoods with hot-water (160 °C, 2 hours) to extract fermentable hemicellulosic sugars. However, this process also releases some lignin/lignin degradation products that are fermentation inhibitors. Lignin is a complex, amorphous polymer formed primarily by oxidative combinatorial coupling of phenylpropanoids. Among the predominant side-chain linkages in lignin, the most reactive are the alkyl-aryl ether linkages. They are susceptible to cleavage under acid conditions; and the ESF biorefinery hot-water extraction (HWE) protocol is inherently a 'mildly' acidic process. To determine if the alkyl-aryl ether linkages are cleaved in this pre-treatment process, model compounds and milled-wood lignin were subjected to HWE. Sugar maple (Acer saccharum) and two paulownia (Paulownia elongata and tomentosa ) wood species were used in this study. Studies on the effect of irradiation on wood prior to HWE were also initiated. From the model compounds utilized in this study it was shown that the beta-O-4 type alkyl-aryl ether linkage is cleaved whereas the beta-5/alpha-O-4 type linkage, also known as phenylcoumaran, remains largely unaffected. These studies also showed that the lignin fraction separated from the hot-water extracts of sugar maple was composed mainly of syringyl units and had relatively high free phenolic hydroxyl group content. Two-dimensional nuclear magnetic resonance spectrometry (2D NMR) was employed to further understand the effect of HWE on lignin samples, which included milled-wood lignin isolated from sugar maple before and after HWE. Dibenzodioxocin structure containing the alkyl-aryl ether linkages was shown to have cleaved during HWE based on 2D NMR. Gas chromatography-mass spectrometry (GC-MS) was used to identify the low-molecular weight phenolic compounds generated during this process. Antioxidizing activity of different fractions isolated in this study was shown to be comparable to that of vitamin C. 3-hydroxytyrosol, a potent antioxidant, was identified in the hot-water extract of P. tomentosa..

ISBN: 9781321338539Subjects--Topical Terms:

1031154
Agriculture, Wood Technology.

Investigating the effect of hot-water extraction on phenolic constituents of selected hardwoods: A study aided by 2D NMR and GC-MS.
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245 1 0 $a Investigating the effect of hot-water extraction on phenolic constituents of selected hardwoods: A study aided by 2D NMR and GC-MS.
300 $a 180 p.
500 $a Source: Dissertation Abstracts International, Volume: 76-03(E), Section: B.
500 $a Adviser: Biljana M. Bujanovic.
502 $a Thesis (Ph.D.)--State University of New York College of Environmental Science and Forestry, 2014.
520 $a The SUNY-ESF biorefinery protocol begins with the pre-treatment of hardwoods with hot-water (160 °C, 2 hours) to extract fermentable hemicellulosic sugars. However, this process also releases some lignin/lignin degradation products that are fermentation inhibitors. Lignin is a complex, amorphous polymer formed primarily by oxidative combinatorial coupling of phenylpropanoids. Among the predominant side-chain linkages in lignin, the most reactive are the alkyl-aryl ether linkages. They are susceptible to cleavage under acid conditions; and the ESF biorefinery hot-water extraction (HWE) protocol is inherently a 'mildly' acidic process. To determine if the alkyl-aryl ether linkages are cleaved in this pre-treatment process, model compounds and milled-wood lignin were subjected to HWE. Sugar maple (Acer saccharum) and two paulownia (Paulownia elongata and tomentosa ) wood species were used in this study. Studies on the effect of irradiation on wood prior to HWE were also initiated. From the model compounds utilized in this study it was shown that the beta-O-4 type alkyl-aryl ether linkage is cleaved whereas the beta-5/alpha-O-4 type linkage, also known as phenylcoumaran, remains largely unaffected. These studies also showed that the lignin fraction separated from the hot-water extracts of sugar maple was composed mainly of syringyl units and had relatively high free phenolic hydroxyl group content. Two-dimensional nuclear magnetic resonance spectrometry (2D NMR) was employed to further understand the effect of HWE on lignin samples, which included milled-wood lignin isolated from sugar maple before and after HWE. Dibenzodioxocin structure containing the alkyl-aryl ether linkages was shown to have cleaved during HWE based on 2D NMR. Gas chromatography-mass spectrometry (GC-MS) was used to identify the low-molecular weight phenolic compounds generated during this process. Antioxidizing activity of different fractions isolated in this study was shown to be comparable to that of vitamin C. 3-hydroxytyrosol, a potent antioxidant, was identified in the hot-water extract of P. tomentosa..
590 $a School code: 0213.
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650 4 $a Chemistry, Biochemistry. $3 1017722
650 4 $a Engineering, Chemical. $3 1018531
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710 2 $a State University of New York College of Environmental Science and Forestry. $b Paper and Bioprocess Engineering. $3 3169421
773 0 $t Dissertation Abstracts International $g 76-03B(E).
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791 $a Ph.D.
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856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3645182