INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY

    WORLD HEALTH ORGANIZATION



    TOXICOLOGICAL EVALUATION OF SOME
    FOOD COLOURS, EMULSIFIERS, STABILIZERS,
    ANTI-CAKING AGENTS AND CERTAIN
    OTHER SUBSTANCES



    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.


    STARCH ACETATE

    Biological Data

    Esterification is achieved by using either acetic anhydride (up to 8
    per cent.) or vinyl acetate (up to 7.5 per cent.). A maximum of 2.5
    per cent. acetyl groups is introduced corresponding to a maximum
    degree of substitution of 0.1.

    Biochemical aspects

    The digestibility of acetylated starches was measured by the
    biochemical oxygen demand of incubated samples. As the acetyl contents
    increased so the BOD values decreased and, in parallel, the
    digestibility. Starch acetates containing 2.5 per cent. acetyl groups
    are only 93.7 per cent. as digestible as native starch (Turner, 1961).
    Digestibility by fungal amyloglucosidase was shown to be 80.5 per
    cent. of that of native starch (Turner, 1961). Caloric values were
    determined in groups of 10 male rats fed 4 weeks on a diet
    supplemented with graded doses of 0, 1.5 g, 3.0 g, 4.5 g and 6.0 g
    dextrose (equivalent to O, 6, 12, 18 and 24 calories). The dose
    response curve was used to estimate the caloric value of supplements
    of 3 g and 4.5 g of acetylated (1.8 per cent. acetyl) or native
    starch. No significant difference was found between the starch samples
    with regard to caloric value (Oser, 1961).

    Acute toxicity

    None available.

    Short-term studies

    Rat. Groups of 10 male rats were fed for 28 days diets containing 60
    per cent. of various starch acetates (the degree of acetylation varied
    from 0, 1.24 per cent., 2 per cent., 2.56 per cent. to 3.25 per
    cent.). Weight gain was reduced in groups receiving starch acetates
    with more than 2 per cent. acetylation but feed efficiency remained
    unaffected. Diarrhoea occurred at 2 per cent. and higher degrees of
    acetylation and there was noticeable caecal enlargement at the same
    levels. No tissue damage or inflammation were noted in association
    with the diarrhoea (Turner, 1961). In another experiment potato starch
    acetates (acetylated to 1.36 per cent.) was fed for 13 weeks to groups
    of 10 male and 10 female rats at levels of 5 per cent., 15 per cent.
    and 45 per cent. of the diet. The 5 per cent. level was fed for only 4
    weeks. No animal died. Growth rates and haematological findings were
    not significantly affected. The relative weights of liver, kidney,
    adrenal, pituitary and thyroid showed some significant differences
    compared with controls, being generally lower except for male
    thyroids. Male caecal weights were higher than controls and distended
    caecal were seen at the 15 per cent. and 45 per cent. dietary levels.
    No other histopathological changes due to starch acetate were seen
    (Feron et al., 1967).

    Long-term studies

    None available

    Comments

    Commercial acetylation processes introduce considerable modifications
    in the starch molecule. An increasing degree of acetylation reduces
    in vitro enzymatic digestibility and leads to diarrhoea and caecal
    enlargement when the product is fed at high dietary levels. The
    short-term study in rats was inadequately designed. However, a
    no-effect level for the study can be derived. In view of the
    comparatively large modification in the starch molecule it would be
    desirable to carry out life-span studies in one species and metabolic
    studies in man.

    EVALUATION

    Level causing no toxicological effects in the rat

    Five per cent. (= 50 000 ppm) in the diet equivalent to 2500 mg/kg
    body weight/day

    Estimate of acceptable daily intake for man

    Temporary acceptance                    mg/kg body weight 

                                                  0-12.5

    Further work required by June 1972

    Adequate 90-day studies in 2 species (one a non-rodent mammal).

    REFERENCES

    Feron, V.J., Til, H. P. and de Groot, A. P., (1967) Report No. R2329
    by Centraal Instituut voor voedingsondrzoek (TNO)

    Oser, M., (1961), Unpublished report No. 79868b & c by Food and Drug
    Research Laboratories Inc., 20 April 1961. Submitted by National
    Starch and Chem. Corp.

    Turner, A. W., (1961) Unpublished report to Avebe, 17 October 1961.
    Submitted by Assoc. Amidonneries de Mais.
    

    See Also:
       Toxicological Abbreviations
       Starch acetate (WHO Food Additives Series 1)
       Starch acetate (WHO Food Additives Series 5)
       Starch acetate (WHO Food Additives Series 17)
       STARCH ACETATE (JECFA Evaluation)