Leung's Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics

role as intermediate in the biosynthesis of
betanin.^5
Red beet color is most stable at pH 4.5–5.5;
it is rather unstable outside this range. There is
evidence of an enzyme present in red beet that
specifically destroys the betanin chromophore
at an optimal pH of 3.35 and a temperature
optimum of 42C.^6 Betacyanin and betax-
anthin decolorizing enzyme with an optimal
pH of 3.4 have recently been reported in beet
root tissue.^7
Red beet pigments are heat labile, especial-
ly in the presence of metals (e.g., Cu, Mn, Fe,
Zn); and at temperatures above 121C, betanin
is rapidly destroyed. Copper is the most effi-
cient catalyst for the breakdown. The color
can be stabilized by sequestrants and/or anti-
oxidants such as citric acid, sorbic acid, and
ascorbic acid;8,9though ascorbic acid has also
been shown to decrease the color stability of
betanin in aqueous solutions.^10
The tinctorial power of betanin is quite
high; however, its concentration in most com-
mercial beet colors is only 1–2%, making it
necessary to use these colors at relatively high
levels to achieve the desired color effects. At
these high levels, the characteristic beet flavor
usually is perceptible. According to a patented
process, the pigment content can be consider-
ably increased, at the same time eliminating
the beet flavor and aroma.11,12

PHARMACOLOGY AND BIOLOGICAL

ACTIVITIES

Betalains and betanin have shown potent

in vitroantioxidant activity. Betanin inhibited

lipid perioxidationin vitromore potently than

catechin13,14and in humans showed have high

bioavailability.^13

TOXICOLOGY

Red beet color has been reported to have

weakly mutagenic activities per Ames test,^15

although these results were not substantiated

by others.^16 Red beet color did not initiate or

promote hepatocarcinogenesis in rats during a

short-term study.^17

USES

Used in coloring various food products.2,18

COMMERCIAL PREPARATIONS

Powdered beet root, juice, concentrated juice,

and spray-dried powder are available in dif-

ferent coloring strengths.

Regulatory Status. Beet powder as a color

additive is approved for food use (§73.40 and

§73.260); exempt from certification.

REFERENCES

See the General References forBAILEY2;MCGUFFIN1&2.

1. B. V. Ford-Lloyd and J. T. Williams,Bot.
   J. Linn. Soc., 71 , 89 (1975).


2. F. Delgardo-Vargas et al.,Crit. Rev. Food
   Sci. Nutr., 40 , 173 (2000).


3. T. J. Mabry and A. S. Dreiding in T. J.
   Mabry et al., eds.,Recent Advances in
   Phytochemistry, Vol. 1, Appleton-
   Century-Crofts, New York, 1968, p. 145.


4. J. B. Harborne in L. Reinhold et al., eds.,
   Progress in Phytochemistry, Vol. 4,
   Pergamon, Oxford, UK, 1977, p. 189.
   5. H. Wyler et al.,Helv. Chim. Acta, 67 , 1348
   (1984).
   6. M. S. Ul’yanova et al.,Dokl. Akad. Nauk
   SSSR, 200 , 990 (1971).
   7. C. C. Shih and R. C. Wiley,J. Food Sci.,
   47 , 164 (1981).
   8. A. F. Fang-Yung and A. V. Khotivari,Isv.
   Vyssh. Uchebn. Zaved., Pishch. Tekhnol.,
   6 , 152 (1975).
   9. N. I. Oragvelidze et al., USSR 565,049
   (1977).

Beet color, red 87