This study delved into the relationship between umami
taste sensitivity
(UTS) and variations in the salivary proteome among 12 healthy nonsmokers
utilizing 4D data-independent acquisition-based proteomics. By assessing
UTS through monosodium l-glutamate (MSG) detection thresholds,
we discovered notable differences: individuals with high UTS detected
umami at significantly lower MSG concentrations (0.20 ± 0.12
mM) compared to their low UTS counterparts (2.51 ± 1.21 mM).
Both groups showed an upregulation of the S100A1 protein under MSG
stimulation, indicating a potent biochemical response to umami stimuli.
The high UTS group exhibited enhanced metabolic pathways including
those for amino acid, lipid, and organic acid biosynthesis, essential
for maintaining taste receptor functionality and enhancing signal
transduction. This group also demonstrated increased activity in cytochrome
P450 enzymes and ribonucleoprotein complexes, suggesting a readiness
to manage metabolic challenges and optimize umami perception. In contrast,
the low UTS group showed adaptive mechanisms, possibly through modulation
of receptor availability and function, with an upregulation of structural
and ribosomal proteins that may support taste receptor production
and turnover. These findings suggest that varying biological mechanisms
underpin differences in umami perception, which could significantly
influence dietary preferences and nutritional outcomes, highlighting
the intricate interplay of genetic, physiological, and metabolic factors
in taste sensitivity.