Toxicological evaluation of some food
    additives including anticaking agents,
    antimicrobials, antioxidants, emulsifiers
    and thickening agents


    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


    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.



         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



         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).


    Short-term studies


         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.,

         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.


         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.


         Not possible with the data available.


    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

    See Also:
       Toxicological Abbreviations
       Hydroxypropyl distarch phosphate  (FAO Nutrition Meetings Report Series 46a)
       Hydroxypropyl distarch phosphate (WHO Food Additives Series 1)
       Hydroxypropyl distarch phosphate (WHO Food Additives Series 6)