Betanidin

Betanidin is a natural pigment that serves as the aglycone (non-sugar form) of betanin, the red-violet pigment found in beets and other plants in the order Caryophyllales. Betalains, the broader pigment class to which betanidin belongs, are nitrogen-containing compounds responsible for red-violet (betacyanins) and yellow (betaxanthins) hues. Betanidin provides the core chromophore that, when glycosylated with glucose, yields betanin.

Natural occurrence: Betanidin occurs in beets (Beta vulgaris) and related species as part of the betalain pigment system. In plants, most pigment is present as glycosylated derivatives such as betanin, with betanidin present in smaller, non-glycosylated forms.

Biosynthesis: In plants, betalains are produced via a tyrosine-derived pathway. Tyrosine is converted to L-DOPA and then to betalamic acid; condensation of betalamic acid with cyclo-DOPA-like units yields betacyanins, with betanidin acting as the aglycone for betanin after glycosylation.

Properties: Betanidin is water-soluble and contributes red-violet coloration. It is typically less abundant and less stable than its glycosylated counterpart betanin, and may be less persistent under storage conditions.

Applications and significance: While betanin is widely used as a food coloring (E162) and beet pigments are studied for antioxidant properties, betanidin itself is primarily of interest in pigment chemistry and plant biochemistry rather than as a commercial dye.

Safety: Betalains, including betanin and related compounds, are generally considered safe for consumption; typical dietary amounts from beet products pose no known risks for the general population.