FAO Nutrition Meetings Report Series 
    No. 46A WHO/FOOD ADD/70.36

    The content of this document is the result of the deliberations of the
    Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
    27 May - 4 June 19691

    Food and Agriculture Organization of the United Nations

    World Health Organization

    1 Thirteenth report of the Joint FAO/WHO Expert Committee on Food
    Additives, FAO Nutrition Meetings Report Series, in press;
    Wld Hlth Org. techn.  Rep. Ser., in press.

    DISTARCH PHOSPHATE (prepared using sodium trimetaphosphate)

    Biological Data

    Native starches are known to contain phosphoric acid esters equivalent
    to 0.004 per cent. P and some potato starches up to 0.1 per cent.
    Distarch phosphate is made by the use of sodium trimetaphosphate which
    cross-links starch chains at an approximate rate of one phosphate link
    per 620 glucopyranose units. The amounts of phosphate introduced are
    at the most 0.04 per cent. P (Graefe, 1964).

    Biochemical aspects

    In vitro digestion of a distarch phosphate using trimetaphosphate by
    salivary, pancreatic and intestinal amylase was measured by the
    production rate of reducing sugar. No deleterious effect was shown on
    enzymic depolymerisation (Rosner, 1960).

    Caloric value and digestibility of a distarch phosphate using
    trimetaphosphate were tested in groups of 10 rats fed for seven days
    on 4g basal diet with either 0.9 g or 3.6 g starch supplement by
    observing the gain in body weight and the organ weights of liver,
    kidney, heart and spleen after the feeding period. No significant
    differences were noted between the modified and the unmodified
    starches (Hixson, 1960). Distarch phosphate using trimetaphosphate of
    undisclosed treatment was fed to groups of male and female rats on 5 g
    diets as 1 g or 2 g supplements over 21 days. Weight gains were
    comparable for modified and unmodified starches tested. Animals
    appeared normal at autopsy (Whistler & Belfort, 1961).

    Acute toxicity


    Animal         Route          LD50                Reference
                             mg/kg body weight

    Mouse, female  oral          >24 000              Hodge, 1954
                                 >19 000              Hodge, 1956

    Rat, female    oral          >20 000              Hedge, 1954
                                 >35 000              Hodge, 1956

    Guinea-pig     oral          > 8 800              Hodge, 1954
                                 >18 000              Hedge, 1956

    Rabbit         oral          > 7 000              Hodge, 1954
                                 >10 000              Hodge, 1956

    Cat            oral          > 6 800              Hedge, 1954
                                 > 9 000              Hodge, 1956

    Only small numbers of animals were used but no deaths occurred from
    the quantities administered. Livers and kidneys of guinea-pigs,
    rabbits and cats showed no histological abnormalities related to the
    administration of the modified starch (Hodge, 1954; Hodge, 1956).

    Short-term studies

    None available.

    Long-term studies

    None available.


    The toxicological information shows that cross-linking by means of
    trimetaphosphate does not affect the digestibility or caloric value to
    any significant extent. Moreover the actual extent of phosphate
    cross-linkage is very small. No short or long-term studies are
    available. The metabolic behaviour of the moieties containing the
    phosphate groups has not been studied. Despite the scanty available
    toxicological information this modified starch may be included in the
    evaluation of the highly modified phosphated distarch phosphates,
    being a preliminary stage in the manufacture of the latter. Adequate
    metabolic studies preferably in man, and 90-day studies in two
    species, one a non-rodent mammal, are required.


    See phosphated distarch phosphate.


    Graefe, G. (1964) "Die Stärke" 16, 158

    Hixson, 0. F. (1960) Unpublished report H-1004 by Rosner-Hixson
    Laboratories 3rd February 1960

    Hodge, H. C. (1954) Unpublished report from University of Rochester,
    Division of Pharmacology & Toxicology, 8th October 1954

    Hodge, H.C. (1956) Unpublished report from University of Rochester,
    Division of Pharmacology & Toxicology, 26th May 1956

    Rosner, L. (1960) Unpublished report H-1004-1 by Rosner-Hixson
    Laboratories, 4th March 1960

    Whistler, R. L. & Belfont, A. M. (1961) Science, 133, 1599

    See Also:
       Toxicological Abbreviations