Gum arabic, also known as gum acacia, is the dried gummy exudate
from tropical and subtropical Acacia senegal trees. The exudate is
a proteinaceous polysaccharide, the protein content ranging from
ca.1.5% to 3% for samples from different producing areas. The
proteinaceous components of eight bulk commercial gum arabic samples,
and for eleven gum specimens secured from Acacia senegal trees show
that their amino acid compositions vary considerably, particularly
with respect to the three major components (hydroxyproline, serine and
proline), although the proportions of other amino acids (e.g.,
alanine, cysteine, isoleucine, methionine, threonine, tyrosine and
valine) are remarkably constant (Anderson et al.,1985). Gum arabic
consists of several high-molecular-weight polysaccharides and their
salts, which on hydrolysis yield arabinose, galactose, rhamnose and
glucoronic acid (Anderson et al., 1983).
This substance was last evaluated for acceptable daily intake for
humans by the Joint FAO/WHO Expert Committee on Food Additives in 1982
(Annex 1, reference 59) when a toxicological monograph was prepared
and an ADI "not specified" was allocated.
Additional data have become available and are summarized and
discussed in the following monograph addendum.
2. BIOLOGICAL DATA
2.1 Biochemical aspects
Groups of three male rats (140-160 g) were given diets containing
0, (control), 1, 4 and 8% (w/w) of gum arabic for 28 days. At autopsy
(following macroscopical examination of all organs), materials for
electron microscopy and for microsomal P-450 assays were secured from
all animals. There were no detectable abnormalities in any of the
organelles in the heart and liver specimens from any of the test
animals and no inclusions nor other pathological changes were
observed. In addition, the data indicated that gum arabic did not
induce cytochrome P-450 or microsomal protein (Anderson et al.,
2.2 TOXICOLOGICAL STUDIES
2.2.1 Special studies on teratogenicity
Twenty male and female Osborne-Mendel (FDA strain) rats,
approximately 4 weeks old, were fed gum arabic ad libitum in their
diet at 0, 1, 2, 4, 7.5 or 15% for 13 weeks before mating. The
animals continued to eat the control or test diet throughout mating
and gestation. After mating was confirmed, the females were placed in
groups of 41-47 animals. During gestation, the treated females
consumed from 683 mg gum/kg bw/day in the 1% group to 10,647 mg gum/kg
bw/day in the 15% group. There were no treatment-related changes in
maternal findings, number of fetuses, fetal viability or external,
visceral or skeletal variations and no terata were seen (Collins
et al., 1987).
3. COMMENTS AND EVALUATION
Further findings from teratology and biochemical studies were
reviewed. It was concluded that the results of these studies did not
modify the previous evaluation. The Committee confirmed the ADI "not
Estimate of acceptable daily intake
ADI "not specified". This term is applicable to a food substance
of very low toxicity which, on the basis of the available data
(chemical, biochemical, toxicological, and other), the total dietary
intake of the substance arising from its use at the levels necessary
to achieve the desired effect and from its acceptable background in
food does not, in the opinion of JECFA, represent a hazard to health.
For that reason, and for reasons stated in individual evaluations, the
establishment of an acceptable daily intake expressed in numerical
form is not deemed necessary. An additive meeting this criterion must
be used within the bounds of good manufacturing practice, i.e., it
should be technologically efficacious and should be used at the lowest
level necessary to achieve this effect, it should not conceal inferior
food quality or adulteration, and it should not create a nutritional
ANDERSON, D.M.W., BRIDGEMAN, M.M.E., FARQUHAR, J.G.K. & McNAB, C.G.A.
(1983). The chemical characterization of the test article used in
toxicological studies of gum arabic (Acacia senegal (L.) Willd).
Int. Tree Crops J. 21, 145-254.
ANDERSON, D.M.W., ASHBY, P., BUSUTTIL, B., KEMPSON, S.A. & LAWSON,
M.E. (1984). Transmission electron microscopy of heart and liver
tissues from rats fed with gum arabic and tragacanth. Toxicology
Letters, 21, 83-89.
ANDERSON, D.M.W., HOWLETT, J.F. & McNAB, C.G.A. (1985). The aminoacid
composition proteinaceous component of gum arabic (Acacia senegal
(L.) Willd). Food Additives and Contaminants, 2, 159-164.
COLLINS, T.F.X., WELSH, J.J., BLACK, T.N., GRAHAM, S.L. & BROWN, L.H.
(1987). Study of the teratogenic potential of gum arabic.
Fd.Chem.Toxic. 25, 815-821.