The basic tastes are sweetness, sourness,
saltiness, bitterness, and umami (appetitive taste). There
are taste buds (containing receptors) for sweetness, sourness, bitterness. Saltiness is tasted using ion channels in the
Glutamic acid is detected by G
protein couple receptor that produces umami taste. The taste receptors for sweet sensation are
T1R2 and T1R3. Those for sourness are
PKD2L1. Those for bitterness are TAS2R
But the spiciness
sensation is different from the basic tastes.
Chili peppers contain capsaicin
compounds. The spicy materials like
peppers, ginger, radish, black peper etc cause a hot or spiciness or pungency or
burning sensation on the tongue. The
sensation is called chemesthesis. It is
caused by a trigeminal nerve reaction along with a normal taste reception. The receptors involved are TRP1 and TRPA1.
chemesthesis the taste is not really due to the taste buds. It is due to the separate nerves that carry
the signals to the brain. The spicy
foods activate the nerve fibers (somatosensory fibres on the tongue) directly. This is a similar sensation as that of
sensation of heat (temperature + pain).