Interactions of homologous aldehydes (hexanal, heptanal, and octanal) and ketones (2-hexanone, 2-heptanone,
and 2-octanone) to salt and alkaline-extracted canola and pea proteins and commercial wheat
gluten were studied using GC/MS. Long-chain aldehyde flavours exhibited higher binding affinity, regardless
of protein type and isolation method. Salt-extracted canola protein isolates (CPIs) revealed the highest
binding capacity to all aldehydes followed by wheat gluten and salt-extracted pea protein isolates
(PPIs), while binding of ketone flavours decreased in the order: PPIs > wheat gluten > CPIs. Two aldolisation
products, 2-butyl-2-octenal and 2-pentyl-2-nonenal, were detected from the interactions between
CPIs with hexanal and heptanal, respectively. Protein thermal behaviour in the presence of these compounds
was analysed by differential scanning calorimeter, where decreased DH inferred potential conformational
changes due to partial denaturation of PPIs. Compared to ketones, aldehyde flavours possessed
much higher ‘‘unfolding capacity’’ (lower DH), which accounted for their higher binding affinities.