Toxicological evaluation of some food
additives including anticaking agents,
antimicrobials, antioxidants, emulsifiers
and thickening agents
WHO FOOD ADDITIVES SERIES NO. 5
The evaluations contained in this publication
were prepared by the Joint FAO/WHO Expert
Committee on Food Additives which met in Geneva,
25 June - 4 July 19731
World Health Organization
Geneva
1974
1 Seventeenth Report of the Joint FAO/WHO Expert Committee on
Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 539;
FAO Nutrition Meetings Report Series, 1974, No. 53.
HYDROXYPROPYL DISTARCH PHOSPHATE
Explanation
Modification is carried out with 0.1% phosphorus oxychloride and
8-10% of propylene oxide. Cross-linkage would be no greater than is
experienced on modification with phosphorus oxychloride alone and
ether linkages would probably not exceed 20 per 100 anhydroglucose
units.
BIOLOGICAL DATA
BIOCHEMICAL ASPECTS
Digestibility was tested in groups of five rats fed for seven
days a basal diet supplemented by 0, 1 g and 3 g modified or control
starch. No difference in weight gain was observed (Prier, 1961).
In a caloric utilization study groups of 10 male rats were fed
for 10 days either unmodified starch or starch modified with 3, 6 or
8% propylene oxide as well as 0.0123% phosphorus oxychloride
equivalent to a degree of substitution ranging from 0.085 to 0.23.
There was a slight decrease in caloric utilization with increasing
degree of modification. Diarrhoea occurred whenever 4 g modified
starch was included in the daily ration but also at the 2 g/day level
with the more highly modified starches. The relative organ weight of
the empty caecum was always increased at the 4 g/day level but also at
the 2 g/day level with the two highly modified starches. Histological
examination of the heart, liver, spleen, kidney and caecum revealed no
obvious abnormalities related to treatment. Similar data were obtained
in a series of tests using starches modified in the intermediate range
of degree of substitution by the use of propylene oxide and phosphorus
oxychloride (Porter, 1971).
TOXICOLOGICAL STUDIES
Short-term studies
Rat
Groups of 10 male rats were fed diets containing 17, 34, 51, or
68% modified starch for 28 days. Growth and body weights were reduced
compared with controls at the two highest levels tested. The relative
organ weights of empty caeca were raised at all levels tested and the
extent of the increase was dose-related. No histological abnormalities
were seen in heart, liver, spleen, kidney and caecum (Porter, 1971).
Groups of 15 male and 15 female rats are fed on diets containing
0, 5, 10 and 25% of a modified starch prepared by treating corn starch
with 0.1% phosphorus oxychloride and 5% propylene oxide (hydroxypropyl
degree of substitution 0.07). The feeding period was 90 days. General
condition, growth, food intake and efficiency, haematology, serum
chemistry and urine analyses were not unfavourably affected at any
dietary level. Diarrhoea did not occur, but the water content of the
faeces and the amount of faeces dry matter/100 g food consumed was
increased at the 10 and 25% feeding level. The caecal weights both
filled and empty were distinctly increased only in the 25% diet-group
in both sexes. Males of this group also showed slightly decreased
weights of adrenals and testicles. Macroscopically no compound-related
differences were observed amongst the various groups. The
histopathological examination has not yet been completed (Til et al.,
1973).
Groups each of 30 weanling rats (FDRL-Wistar) equally divided by
sex, were maintained on diets containing 5, 10 or 25% of the starch
modified with 10% propylene oxide or 25% unmodified starch, for a
period of 90 days. Four rats died during the test period, but deaths
were not treatment-related. At the highest level of intake of the
modified starch, the faeces were soft and bulky during the first seven
weeks of test, but normal for the rest of the test period. Growth food
intake, and food efficiency of all groups was normal with the
exception of a slight decrease in feed efficiency in males in the 25%
modified starch group. Haematologic, biochemical and urine analysis
were within normal limits. At autopsy, absolute and relative organ
weight of test and control animals were comparable with exception of
the caecum. Caecum plus contents showed a treatment-co-related
response, however, in the case of the empty caeca, significant
increase in weight was only observed in males on the 25% diet.
Histological studies showed that about 40% of the rats in the test
groups had calcerous deposits within the renal pelvis and/or pelvic
epithelium (5% group, 18/30, 10% group, 20/30, 25% group, 22/30). No
other compound-related changes were observed with the exception of a
slight thinning of the caecum, which were cytologically normal (Food &
Drug Research Laboratories, Inc., 1973).
Long-term studies
None available.
Comments:
Data from caloric utilization studies are available. The most
significant effect observed in one short-term study in rats was the
presence of calcareous deposits in the renal pelvis of test animals.
This effect may be related to the composition of the basal diet. A
second short-term rat study is in progress.
EVALUATION
Not possible with the data available.
REFERENCES
Food & Drug Research Laboratories Inc. (1973) Unpublished report
submitted to Corn Refiners Association, Inc.
Porter, M. W. (1971) Unpublished report submitted to WHO by A. E.
Staley Manufacturing Co.
Prier, R. T. (1961) Unpublished report of Wisconsin Alumni Research
Foundation No. 1031347/8, submitted by Stein, Hall & Co., Inc.
Til, H. P. et al. (1973) Unpublished report No. R 4082 by Centraal
Instituut voor Voedingsonderzoek TNO