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.

    DISTARCH GLYCEROL

    Explanation

         Treatment with epichlorhydrin under alkaline conditions up to 0.3%
    tends to produce cross-linking at a rate of one glycerol diether
    linkage per 220 - glycopyranose units.

    BIOLOGICAL DATA

    BIOCHEMICAL ASPECTS

         Much evidence in the literature points to etherified starches
    being somewhat resistant to enzymic degradation. Probably small
    fragments containing the ether linkage will remain and will not be
    absorbed readily. Any material absorbed is likely to be excreted by
    the kidney. Ne direct experimental evidence exists for this particular
    hypothesis (French, 1960). The metabolic fate of methyl-glucose is
    cited as collateral evidence. Although methylglucose is absorbed by
    rats (Sols, 1956) no demethylation is believed to occur (Csáky &
    Wilson, 1956) and excretion is essentially quantitative (Csáky &
    Glenn, 1957). The in vitro digestibility by amyloglucosidase of
    distarch glycerol (0.3% epichlorhydrin) was shown to be 98.3% of that
    of unmodified starch (Kruger, 1970). The caloric values of two
    starches treated at levels of 0.07% and 0.50% epichlorhydrin were
    estimated in groups of 10 weanling male rats by comparing the weight
    gain obtained after feeding for 28 days a basal diet supplemented with
    3 g of each starch against a dose-response curve obtained by feeding
    daily sucrose supplements of 0, 1.5 g, 3 g, 4.5 g and 6 g equivalent
    to approximately 0, 6, 12, 18 and 24 calories. Distarch glycerols were
    only slightly lower in caloric value than unmodified starch, the
    differences not being significant (Oser, 1961).

    TOXICOLOGICAL STUDIES

    Short-term studies

    Rat

         Three groups of 10 male and 10 female rats were fed for 90 days
    unmodified starch or starch treated with 0.07% or 0.50% epichlorhydrin
    at 71% of their diet. Growth rate, appearance, behaviour and food
    intake were similar in all three groups. Haematological investigations
    showed no abnormalities related to the feeding of modified starches.
    Non-protein nitrogen blood levels and blood sugar levels remained
    normal in all groups. The weights of all major organs were normal and
    no abnormal gross or histopathological changes related to treatment
    were seen (Oser, 1961).

    Long-term studies

         None available.

    Comments:

         The feeding studies with rats show that the modified starch is
    well utilized. The available evidence for the group of modified
    starches considered indicate that caecal enlargement without
    associated histopathological changes is without toxicological
    significance. The short-term rat study shows no adverse effects at the
    high dietary level used. No long-term study on this modified starch is
    available and collateral evidence from the long-term and reproduction
    studies with hydroxypropyl distarch glycerol, a more highly modified
    starch, indicates that the glycerol linkage is causing no adverse
    effects.

    EVALUATION

    Estimate of acceptable daily intake for man

         Not limited.*

    REFERENCES

    Csáky, T. Z. & Glenn, J. E. (1957) Amer. J. Physiol., 188. 159

    Csáky, T. Z. & Wilson, J. E. (1956) Biochim. Biophys. Acta., 22, 185

    French, D. (1960) Unpublished report

    Kruger, L. (1970) Unpublished reports Nos 405 & 406 submitted by
         National Starch and Chemical Corporation

    Oser, B. L. (1961) Unpublished report of Food and Drug Research
         Laboratories Inc., submitted by National Starch and Chemical
         Corporation

    Sols, A. (1956) Rev. esp. Fisiol., 12, 17

              

    *    See relevant paragraph in the seventeenth report, pages 10-11

    See Also:
       Toxicological Abbreviations
       Distarch glycerol  (FAO Nutrition Meetings Report Series 46a)
       Distarch glycerol (WHO Food Additives Series 1)
       DISTARCH GLYCEROL (JECFA Evaluation)