4. Conclusion
From the current investigation, flavour class, flavour carbon
number, protein source, and protein isolation method were all
found to have a significant impact on protein–flavour binding
performance. Ketone flavours with lower carbon number were
retained least by proteins, leaving a high volatile flavour concentration
both at sample headspace and within food matrix. Different
sources of proteins showed different flavour binding behaviours as
a result of their inherent protein structure and amino acid composition.
As different protein isolation methods were used, saltextracted
proteins exhibited higher flavour binding abilities than
alkaline extracted ones, except for PPIa retaining more aldehydes
than PPIs. For wheat gluten, the capacity to bind with aldehydes
or ketones fell between CPIs and PPIs. Formation of new volatile
flavour by-products showed the potential to distort the original
food flavour profile due to the formation of new volatile compounds.
The changes observed in protein thermal properties indicated
that protein conformational changes due to protein–flavour
interactions increase protein–flavour binding. Careful selection and use of flavour compounds and protein sources when manufacturing
plant protein-based food products are necessary to effectively
delivery a satisfactory sensory flavour profile acceptable to
consumers.
Acknowledgements
The authors are grateful for support from Wayne D. Buchannon
and Dr. Tom Ward in Manitoba Chemical Analysis Laboratory
(MCAL, University of Manitoba) for their technical assistance in
GC/MS analysis. Financial support provided by the National Science
and Engineering Research Council of Canada (NSERC) and
University of Manitoba Faculty of Graduate Studies are gratefully
acknowledged.