On Food and Cooking

depicted in the 16th century. Table beets are
about 3% sugar and some large animal-feed
varieties are 8%; in the 18th century, selection
for sugar production led to sugar beets with
20% sucrose.
Colored beets owe their red, orange, and
yellow hues to betain pigments (p. 268),
which are water-soluble and stain other
ingredients. There are variegated varieties
with alternating red layers of phloem tissue
and unpigmented layers of xylem (p. 262);
they look their best in raw slices because
cooking causes cell damage and pigment
leakage. When we eat beets, the red pigment
is usually decolorized by high stomach acidity
and reaction with iron in the large intestine,
but people sometimes excrete the intact
pigment, a startling but harmless event. The
persistent firmness of cooked beets is caused
by phenolic reinforcement of the cell walls, as
in bamboo shoots and water chestnuts (p.
283).