Understanding sub-critical water hydrolysis of proteins by mass: applications in proteomics and biorefining

Powell, Thomas (2018). Understanding sub-critical water hydrolysis of proteins by mass: applications in proteomics and biorefining. University of Birmingham. Ph.D.

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Abstract

Sub-critical water (SCW) hydrolysis has previously been used in the extraction of antioxidant compounds from a variety of food wastes, in-particular those which are rich in protein. The brewing industry generates high volumes of waste. The most abundant component, brewers’ spent grain (BSG), is high in protein content. The work presented in this thesis aimed to investigate the SCW extraction of antioxidant compounds from BSG.

Whilst SCW hydrolysis has proved effective in the extraction of antioxidants from a range of compounds its mechanism of action has not been thoroughly investigated. High performance liquid chromatography (HPLC) coupled to tandem mass spectrometry (MS/MS) was used to analyse peptide production from the SCW hydrolysis of proteins. Sites of cleavage were identified and a mechanism of action of SCW on proteins was postulated. The results from this analysis raised the possibility of using SCW as a proteolytic reagent during proteomics experiments. Approaches for SCW-based proteomics were further explored by investigating SCW induced amino acid side chain modifications to aid peptide identification.

To assess the antioxidant capacity of mixtures generated via SCW hydrolysis oxygen radical absorbance capacity, reducing power and comet assays were used. The decomposition products responsible for antioxidant capacity were characterised using MS/MS.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):