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\(Pyrococcus\) \( furiosus\) amylase as a Candidate Sterilisation Time-Temperature Integrator

Brown, Ian (2010)
Ph.D. thesis, University of Birmingham.

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Abstract

Thermal treatment is the most common method used by industry to ensure food is safe for consumption and to increase storage life. To ensure safety, food is often over processed, which can significantly affect its nutritional value as well as taste and flavour attributes. In this study a candidate sterilisation time-temperature integrator (TTI) from the hyperthermophilic Pyrococcus furiosus \(\alpha\)amylase is investigated.

Reliability and accuracy of the TTIs was determined by exposure to various isothermal and non-isothermal industrially relevant temperature profiles. The integrated temperature history obtained by the TTIs correlated generally well with the data obtained from thermocouples installed, although the error increased with hold time of heat treatment. The work showed that the TTIs can be used reliably over a range (3-25 minutes at 121°C) which is relevant for conditions of thermal sterilisation. This was measured by developing a new assay technique for assaying the activity of hyperthermophilic \(\alpha\)-amylase within the food industry. The assay was calibrated against more laboratory relevant assays and computational models.

The kinetics and mechanism of thermal denaturation of Pyrococcus furiosus \(\alpha\)-amylase was determined through FT-IR, DSC and CD techniques. It was found that through thermal denaturation after the melting temperature (Tm), the enzyme unfolded by first order kinetics from a \(\alpha\)-helical structure, through \(\alpha\)-sheet structure to aggregation of the enzyme.

Type of Work:Ph.D. thesis.
Supervisor(s):Fryer, P. J. and Cox, Philip William
School/Faculty:Colleges (2008 onwards) > College of Engineering & Physical Sciences
Department:School of Chemical Engineering
Subjects:TP Chemical technology
Institution:University of Birmingham
ID Code:1369
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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