INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
WORLD HEALTH ORGANIZATION
TOXICOLOGICAL EVALUATION OF SOME
FOOD COLOURS, EMULSIFIERS, STABILIZERS,
ANTI-CAKING AGENTS AND CERTAIN
OTHER SUBSTANCES
FAO Nutrition Meetings Report Series
No. 46A WHO/FOOD ADD/70.36
The content of this document is the result of the deliberations of the
Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
27 May - 4 June 19691
Food and Agriculture Organization of the United Nations
World Health Organization
1 Thirteenth report of the Joint FAO/WHO Expert Committee on Food
Additives, FAO Nutrition Meetings Report Series, in press;
Wld Hlth Org. techn. Rep. Ser., in press.
DISTARCH PHOSPHATE (prepared using sodium trimetaphosphate)
Biological Data
Native starches are known to contain phosphoric acid esters equivalent
to 0.004 per cent. P and some potato starches up to 0.1 per cent.
Distarch phosphate is made by the use of sodium trimetaphosphate which
cross-links starch chains at an approximate rate of one phosphate link
per 620 glucopyranose units. The amounts of phosphate introduced are
at the most 0.04 per cent. P (Graefe, 1964).
Biochemical aspects
In vitro digestion of a distarch phosphate using trimetaphosphate by
salivary, pancreatic and intestinal amylase was measured by the
production rate of reducing sugar. No deleterious effect was shown on
enzymic depolymerisation (Rosner, 1960).
Caloric value and digestibility of a distarch phosphate using
trimetaphosphate were tested in groups of 10 rats fed for seven days
on 4g basal diet with either 0.9 g or 3.6 g starch supplement by
observing the gain in body weight and the organ weights of liver,
kidney, heart and spleen after the feeding period. No significant
differences were noted between the modified and the unmodified
starches (Hixson, 1960). Distarch phosphate using trimetaphosphate of
undisclosed treatment was fed to groups of male and female rats on 5 g
diets as 1 g or 2 g supplements over 21 days. Weight gains were
comparable for modified and unmodified starches tested. Animals
appeared normal at autopsy (Whistler & Belfort, 1961).
Acute toxicity
Animal Route LD50 Reference
mg/kg body weight
Mouse, female oral >24 000 Hodge, 1954
>19 000 Hodge, 1956
Rat, female oral >20 000 Hedge, 1954
>35 000 Hodge, 1956
Guinea-pig oral > 8 800 Hodge, 1954
>18 000 Hedge, 1956
Rabbit oral > 7 000 Hodge, 1954
>10 000 Hodge, 1956
Cat oral > 6 800 Hedge, 1954
> 9 000 Hodge, 1956
Only small numbers of animals were used but no deaths occurred from
the quantities administered. Livers and kidneys of guinea-pigs,
rabbits and cats showed no histological abnormalities related to the
administration of the modified starch (Hodge, 1954; Hodge, 1956).
Short-term studies
None available.
Long-term studies
None available.
Comments
The toxicological information shows that cross-linking by means of
trimetaphosphate does not affect the digestibility or caloric value to
any significant extent. Moreover the actual extent of phosphate
cross-linkage is very small. No short or long-term studies are
available. The metabolic behaviour of the moieties containing the
phosphate groups has not been studied. Despite the scanty available
toxicological information this modified starch may be included in the
evaluation of the highly modified phosphated distarch phosphates,
being a preliminary stage in the manufacture of the latter. Adequate
metabolic studies preferably in man, and 90-day studies in two
species, one a non-rodent mammal, are required.
EVALUATION
See phosphated distarch phosphate.
REFERENCES
Graefe, G. (1964) "Die Stärke" 16, 158
Hixson, 0. F. (1960) Unpublished report H-1004 by Rosner-Hixson
Laboratories 3rd February 1960
Hodge, H. C. (1954) Unpublished report from University of Rochester,
Division of Pharmacology & Toxicology, 8th October 1954
Hodge, H.C. (1956) Unpublished report from University of Rochester,
Division of Pharmacology & Toxicology, 26th May 1956
Rosner, L. (1960) Unpublished report H-1004-1 by Rosner-Hixson
Laboratories, 4th March 1960
Whistler, R. L. & Belfont, A. M. (1961) Science, 133, 1599