WORLD HEALTH ORGANIZATION
WHO Food Additives Series 1972, No. 1
TOXICOLOGICAL EVALUATION OF SOME
ENZYMES, MODIFIED STARCHES AND
CERTAIN OTHER SUBSTANCES
The evaluations contained in this publication were prepared by the
Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
16-24 June 19711
World Health Organization
Geneva
1972
1 Fifteenth Report of the Joint FAO/WHO Expert Committee on Food
Additives, Wld Hlth Org. techn. Rep. Ser., 1972, No. 488; FAO
Nutrition Meetings Report Series, 1972, No. 50.
The monographs contained in the present volume are also issued by the
Food and Agriculture Organization of the United Nations, Rome, as FAO
Nutrition Meetings Report Series, No. 50A
(c) FAO and WHO 1972
ACETYLATED DISTARCH PHOSPHATE
Modification is usually performed by the use of up to 0.1 per cent. of
phosphorus oxychloride and 5 per cent. acetic anhydride. Vinyl
acetate may be used as an alternative acetylating agent. Maximum
acetylation amounts usually to 2.5 per cent. acetyl groups.
Biological data
Biochemical aspects
The digestibilities in vitro by pancreatin and porcine mucosal
enzymes of acetylated distarch phosphates, modified to 1.6 per cent.
and 2.3 per cent. acetyl content, were found to be 93 per cent. and 81
per cent. respectively of that of unmodified starch (Leegwater, 1971).
Short-term studies
Rat
Groups of 10 male and 10 female rats were fed 0, 25 and 50 per cent.
of two different modified starches (acetic anhydride and vinylacetate
modified) in their diet for 8 weeks. Body-weights of animals on the
higher test level were somewhat lower than at the 25 per cent. level
and also lower than controls in both sexes. However, the differences
were not statistically significant. The faecal water content was
variable and could not be related to dietary dosage levels.
Production of faecal dry matter was increased in both sexes at the
higher level tested and slightly so at the 25 per cent. dietary level.
The incidence of diarrhoea was insignificant. A dose-related increase
in caecal weight occurred in both sexes. No histological abnormality
of the enlarged caeca was noted (de Groot & Spanjers, 1970).
Pig
Groups of 4 male and 4 female pigs were given 0, 35 or 70 per cent. of
modified starch in their diet over 14-1/2 weeks. Growth rate and food
consumption were satisfactory. Haematology, blood chemistry and
urinalysis revealed no treatment-related abnormalities.
Ophthalmoscopy showed no abnormalities associated with the test
substance. Organ weight, gross and histopathology revealed no
abnormalities in test or control groups. Three pigs in the higher
test group died suddenly at various intervals during the test without
any evidence pointing to the cause of their death. One pig in the
higher test group and another in the 35 per cent. group showed
evidence of neurological malfunction. The animal on 70 per cent. test
substance died, that on the lower dietary level recovered. No
histological evidence of nervous system involvement was noted in these
two nor in any other animal (Shillam et al., 1971).
Man
Twelve volunteers consumed on each of 4 successive days, 60 g
acetylated distarch phosphates of either 1.6 per cent. or 2.33 per
cent. acetyl content. No abnormalities were observed as regards
frequency and amount of faeces as well as faecal water and lactic acid
content. No other adverse effects were noticed (Pieters et al.,
1971).
Long-term studies
Rat
Groups of 30 male and 30 female rats were fed two different modified
starches (acetic anhydride and vinylacetate modified) at levels of 0,
5, 10 and 30 per cent. in their diet for 104 weeks. Appearance,
behaviour, food consumption and mortality were not adversely affected
nor was diarrhoea observed at any level. Growth was slightly
depressed at the highest dietary level with both modified starches.
Haematology, serum chemistry and urinalysis revealed no effects
related to treatment in any group. There was a dose-related increase
in the caecal weight in both sexes at the 30 per cent. level but in
males only at the 10 per cent. level. All other organ weights showed
no treatment-related changes. No gross or microscopic pathological
abnormalities were noted which could be related to the test substances
or which would point to any carcinogenic effects or to any compound
related effects. The caeca appeared remarkably normal (Til et al.,
1971a).
Reproduction studies
Rat
A three generation study was performed using 5 males and 10 females
for the P generation and 10 males and 20 females of the F1b and F2b
to produce successive generations by mating at week 12 and 20 after
weaning. The F3b generation was kept for 3 weeks after weaning and
then sacrificed for histopathological study. The P, F1b and F2b
parents were used for determination of implantation sites. The test
material, fed at 10 per cent. of the diet consisted of a starch
modified with 5 per cent. acetic anhydride and 0.02 per cent.
phosphorus oxychloride (D.S. of 0.093) and another starch modified
with 4.5 per cent. vinylacetate and 1.2 per cent. phosphorus
oxychloride (degree of substitution of 0.064, 0.04 per cent, P
introduced). No adverse effects were noted in respect of health,
behaviour, mortality, growth, fertility, litter size, resorption
quotient, weaning weight of pups or mortality of young. Caecal
weights were only increased in tests using starch modified with acetic
anhydrides. Gross pathology of the F3b generation revealed a
significant difference in the average thyroid weights. Gross
examination at autopsy did not reveal any pathological changes
attributable to the ingestion of the starch but histopathology is
still outstanding (Til et al., 1971b).
Special studies
Groups of 10 male and 10 female rats were fed 0, 25 or 50 per cent. of
two different modified starches (acetic anhydride and vinylacetate
modified) in a low residue diet for 7 days followed by the additional
feeding of 4 per cent. cellulose for 3 days. The body-weights of all
animals fed 50 per cent. modified starch were somewhat lower than
those of the controls. Production of faecal dry matter was increased
in the higher groups and less so at the 25 per cent. level. Diarrhoea
occurred at the higher level with both modified starches. The
addition of 4 per cent. cellulose had no effect on the severity or
frequency of the diarrhoea. At the higher level there was also some
loss of hair in both sexes (de Groot and Spanjers, 1970).
Comments
The feeding studies with rat and pig show that these modified starches
are well utilized. The long-term and reproduction studies in rats
indicate no unusual adverse effects apart from caecal enlargement.
The suddenness of the death of some of the animals in the pig study
indicates an aberrant effect not related to the feeding of modified
starches. This is reinforced by the absence of any pointer to a
target organ. The available evidence for the group of modified
starches considered suggests that this finding, when not associated
with any histopathological changes, is of little toxicological
significance. It is thus appropriate to use the long-term and
reproduction studies for evaluation.
EVALUATION
Temporarily not limited.*
Further work required by 1973
Histological report to complete the reproduction study in the rat.
REFERENCES
de Groot, A. P. & Spanjers, M. Th. (1970) Unpublished report No. R
3096 by Centraal Instituut voor Voedingsonderzoek
Leegwater, D. C. (1971) Unpublished report No. R 3431 by Centraal
Instituut voor Voedingsonderzoek
Pieters, J. J. L., van Staveren, W. A. & Brinkhuis, B. G. A. M. (1971)
Unpublished report No. R 3433 by Centraal Instituut voor
Voedingsonderzoek
* Except for good manufacturing practice.
Shillam K. W. G., Medd, R. K., Loveridge, G. G., Street, A. E.,
Hagne, P. & Spicer, E. J. F. (1971) Unpublished report No. 3978/71/136
by Huntingdon Research Centre
Til, H. P., Spanjers, M. Th., van der Meulen, H. C. & de Groot, A. P.
(1971a) Unpublished report No. R 3351 by Centraal Instituut voor
Voedingsonderzoek
Til, H. P., Spanjers, M. Th. & de Groot, A. P. (1971b) Report No. 3403
of Centraal Instituut voor Voedingsonderzoek, submitted to WHO