Jackson, Julia Emma (2007) The development of methods for the selective capture and characterisation of fragrances and flavours from nature. PhD thesis, University of Warwick.

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Abstract

The chemical senses of taste and smell are the two least well understood of our
senses. Recent advances in our understanding of the genetic and molecular
mechanisms have led to increasing interest in olfaction and gustation. Amongst the
practical applications of fragrances and flavours are commercial consumer products.
The primary source for inspiration for these is nature and the work discussed in this
thesis addresses methods for isolating selected aroma and taste molecules from
natural sources, for use as new ingredients in food and fragrance applications.
The methods are designed to deal with the challenges of isolating and identifying
species present at very low concentrations (as low as parts per trillion), of unstable
nature and with the desire to target specific functional groups. Carbonyl and thiol
compounds have been selected for trapping due to their interesting fragrance and
flavour characteristics respectively.
A portable reactive trap has been designed, built, and tested to isolate aldehyde (or
ketone) compounds from the headspace of living plants. The trap uses the
derivatising reagent, 0-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine hydrochloride
coated on to a solid sorbent, Tenax TA'-"'. Reagents with immobilised reactive
groups capable of selective reacting with thiol compounds have been investigated
and the proof of principle has been illustrated for three different methods.
The nature identical status of the cooling compound, L-monomenthyl succinate, has
been demonstrated by using highly sensitive and selective analytical techniques to
identify this compound in the berries and leaves of plant Lycium barbarum. A
preparative liquid chromatography system was used to simplify plant extracts which
were subsequently analysed using nano liquid chromatography-electrospray
ionisation-tandem mass spectrometry (nLC-ESI-MS/MS). This system could be
applied to the analysis of other natural source extracts.

Item Type:	Thesis (PhD)
Subjects:	T Technology > TP Chemical technology
Library of Congress Subject Headings (LCSH):	Odors -- Analysis, Odors -- Biotechnology, Flavor -- Analysis, Flavor -- Biotechnology, Carbonyl compounds, Thiols, Food additives
Official Date:	July 2007
Dates:	Date Event July 2007 Submitted
Institution:	University of Warwick
Theses Department:	Department of Biological Sciences
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Scrivens, Jim
Sponsors:	Imperial Chemical Industries PLC
Extent:	xx, 239 leaves
Language:	eng

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