Production of prebiotic rich extracts from lignocellulosic biomass using subcritical water within the context of biorefining

Kalnins, Raitis (2017). Production of prebiotic rich extracts from lignocellulosic biomass using subcritical water within the context of biorefining. University of Birmingham. Ph.D.

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Abstract

Functional food ingredients such as prebiotics are emerging as effective tools for managing the risks associated with gastrointestinal diseases and gut related dysfunctions. This work explores the production of prebiotic rich extracts from two sources of lignocellulosic biomass – energy crop \(Miscanthus\) \(χ\) \(giganteus\), and oat (\(Avena\) \(sativa\)) husks, an agricultural by-product. Whilst most of the research to date has been focusing on the utility of cellulose, the hemicellulose and lignin fractions have been underutilised. This work expands the value of the hemicellulose fraction by extracting the prebiotic xylo-oligosaccharides (XOS) and other hemicellulose derived products using environmentally benign sub-critical water in a 0.5 L stirred batch reactor at temperatures between 120-220°C with residence times 0-77 min, and 0.5-13% (w/v) biomass loading. The extracts were analysed with HPAEC-PAD, HPLC and colorimetric assays. Almost complete hemicellulose solubilisation was achieved, and highest yields of prebiotic (DP 2-5) XOS were observed at 170°C and 35-77 min corresponding to 44-56% with little amounts of carbohydrate degradation products and low total phenolic contents. Although higher yields were achieved with oat husks, the XOS extractability was comparable between the biomass sources. Higher extraction severities resulted in further XOS depolymerisation into monosaccharides and eventual formation of furfural and 5-HMF.

Type of Work:	Thesis (Doctorates > Ph.D.)
Award Type:	Doctorates > Ph.D.
Supervisor(s):	Supervisor(s) Email ORCID Simmons, Mark J. H. UNSPECIFIED UNSPECIFIED Cox, Philip William UNSPECIFIED UNSPECIFIED Leeke, Gary UNSPECIFIED UNSPECIFIED Santos, Regina UNSPECIFIED UNSPECIFIED
Licence:
College/Faculty:	Colleges (2008 onwards) > College of Engineering & Physical Sciences
School or Department:	School of Chemical Engineering
Funders:	None/not applicable
Subjects:	T Technology > TP Chemical technology
URI:	http://etheses.bham.ac.uk/id/eprint/7479

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