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 GLYCEROL
Modification is carried out with epichlorhydrin to a maximum of 0.3
per cent. and acetic anhydride to a maximum of 8 per cent. The amount
of acetyl groups introduced does not exceed 2.5 per cent. Further
treatment, such as bleaching is often carried out.
Biological data
Biochemical aspects
The in vitro digestibility of acetylated distarch glycerol (0.3 per
epichlorhydrin, 1.2 or 2.5 per cent. acetyl content) varies with the
acetyl content but is not affected by cross-linkage. At 1.2 per cent.
acetylation some 82 per cent. of the modified starch are digestible,
at 2.5 per cent. only 68.5 per cent. are hydrolysed enzymatically
(Kruger, 1970). The caloric value was determined by reference to a
dose-response curve established in groups of 10 male rats given a
basic diet with graded supplements of 0, 0.75 g, 1.5 g, 3.0 g and 4.5
g sucrose equivalent to 0, 3, 6, 12 and 18 calories per day. Starches
modified by the use of 0.1 per cent. epichlorhydrin + 5.5 per cent.
acetic anhydride and. 0.3 per cent. epichlorhydrin + 5.5 per cent.
acetic anhydride were tested against native starch at levels of
supplementation of 1.5 g and 3.0 g per day for 28 days. Weight gain
on modified starch supplement was slightly reduced compared with that
on unmodified starch. All rats remained normally active and healthy.
The caloric estimates were similar for both levels of epichlorhydrin
treatment (Oser, 1961).
Short-term studies
Rat
Groups of 15 male and 15 female rats were fed for 90 days on diets
containing 50 per cent. either native or modified starch (0.3 per
cent. epichlorhydrin + 10.5 per cent. acetic anhydride). The growth
rate of male rats was significantly lower compared with controls on
unmodified starch. The full and empty caecal weights of both male and
female rats in the test groups were significantly greater than in
controls. Haematology, blood chemistry, urinalysis, organ weights and
gross as well as histological examination were normal (Oser, 1964).
Comments
The feeding studies with rats show that the modified starch is well
utilized. The available evidence for the group of modified starches
considered suggests that caecal enlargement without associated
histopathological changes is of little toxicological significance.
The short-term rat study shows no other significant effects related to
treatment, the observed growth depression being the obvious result of
the only high dietary level used. No long-term study is available but
the collateral evidence from starch acetate and distarch glycerol
indicates that neither of the modifications singly applied cause any
adverse effects.
EVALUATION
Temporarily not limited.*
Further work required by 1973
Histological reports to complete the 2-year and reproduction rat
studies on starch acetate.
Histological reports to complete the 2-year and reproduction rat
studies on hydroxypropyl distarch glycerol.
REFERENCES
Kruger, L. (1970) Unpublished reports Nos 405 and 406 submitted by
National Starch & Chemical Co.
Oser, M. (1961) Unpublished report of Food and Drug Research
Laboratories Inc. No. 81774, submitted by the National Starch and
Chemical Co.
Oser, B. L. (1964) Unpublished report of Food and Drug Research
Laboratories Inc. No. 85554, submitted by the National Starch and
Chemical Co.
* Except for good manufacturing practice.