WHO Food Additives Series 1972, No. 1


    The evaluations contained in this publication were prepared by the
    Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
    16-24 June 19711

    World Health Organization




    1 Fifteenth Report of the Joint FAO/WHO Expert Committee on Food
    Additives, Wld Hlth Org. techn. Rep. Ser., 1972, No. 488; FAO
    Nutrition Meetings Report Series, 1972, No. 50.

    The monographs contained in the present volume are also issued by the
    Food and Agriculture Organization of the United Nations, Rome, as FAO
    Nutrition Meetings Report Series, No. 50A

    (c) FAO and WHO 1972


    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 68-81 per
    cent. of that of native starch (Turner, 1961; Kruger, 1970).  The
    digestibility of starch acetate (containing 1.98 per cent. acetyl
    groups by pancreatin and porcine mucosal enzymes was found to be 90
    per cent. of that of the unmodified starch (Leegwater, 1971).  Caloric
    value was determined in groups of 10 male rats fed for 4 weeks a diet
    supplemented with graded doses of 0, 1.5 g, 3.0 g, 4.5 g and 6.0 g
    dextrose (equivalent to 0, 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).

    Short-term studies


    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, 2, 2.56 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 acetate (acetylated to 1.36 per
    cent.) was fed for 13 weeks to groups of 10 male and 10 female rats at
    levels of 5, 15 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 caeca were seen at the 15 per cent. and 45 per

    cent. dietary levels.  No histopathological changes due to starch
    acetate were seen (Feron et al., 1967).

    In a further experiment starch acetate (acetylated to 1.98 per cent.)
    was fed to groups of 10 male and 10 female rats for 8 weeks at dietary
    levels of 25 per cent. and 50 per cent.  No effects were noted on
    growth and body-weight.  Water content of faeces and faecal
    production, as measured by dry matter content, showed no consistent
    effects but there was a tendency towards increased faecal dry matter
    at the 50 per cent. dietary level in both sexes.  No diarrhoea was
    observed at any dietary level.  Caecal weight and caecal enlargement
    occurred in a dose-related manner in all treatment groups.  However,
    histological examination revealed no abnormality of the caeca examined
    (de Groot & Spanjers, 1970).


    Twelve volunteers consumed on each of 4 consecutive days 60 g starch
    acetate with 1.98 per cent. acetyl content.  No effect was noted on
    frequency and amount of faeces, faecal water or lactic acid content.
    No other adverse effects were noticed (Pieters et al., 1971).

    Long-term studies


    Groups of 30 male and 30 female weanling rats were fed on diets
    containing 0, 5, 10 and 30 per cent. of starch acetate (acetylated to
    1.98 per cent.) for 2 years.  No significant differences were observed
    with respect to behaviour, general health and mortality.  Growth and
    food consumption were essentially similar to those of the controls.
    Production of faeces during weeks 11 and 12 showed no dose-related
    differences among the various groups.  Haematology, serum chemistry
    and serum enzymes as well as urinalysis showed no effects related to
    the administration of the test material.  Among organ weights only the
    caecal weight of male rats showed a dose-related increase at 10 per
    cent. and higher levels and the caecal weight of female rats was
    increased at the 30 per cent. level compared with controls.  No other
    significant changes were noted which could be ascribed to the test
    substance.  The histological examination is still incomplete (Til et
    al., 1971a).

    Reproduction studies


    A three generation study was performed using 5 males and 10 females
    for the P generation and 10 males and 20 females of the F1b and
    F2b to produce successive generations by mating at week 12 and 20 
    after weaning.  The F3b generation was kept for 3 weeks after 
    weaning and then sacrificed for histopathological study.  The P, 
    F1b and F2b parents were used for determination of 

    implantation sites.  The test material, fed at 10 per cent. of the 
    diet consisted of starch modified with 5 per cent. acetic anhydride 
    (degree of substitutions 0.079). No adverse effects were noted 
    regarding health, behaviour, mortality, body-weights, fertility,
    litter size, resorption quotient, weaning weight of pups or mortality 
    of young.  Caecal weights were increased. Gross pathology of the 
    F3b generation revealed that kidney weights in females differed 
    in a statistically significant way from controls but histopathology 
    is still underway (Til et al., 1971b).

    Special studies

    Groups of 10 male and 10 female rats were given 25 per cent. and 50
    per cent. of starch acetate (acetylated to 1.98 per cent.) in a low
    residue diet for 7 days.  Thereafter 4 per cent. cellulose was added
    for a further 3 days.  Body-weights were slightly reduced in both
    sexes at the 50 per cent. level after 7 days.  Faecal dry matter was
    increased in all test groups but not in a dose-related manner.  Slight
    diarrhoea occurred only at the 50 per cent. level in both sexes and
    this was unaffected by the feeding of additional cellulose in the
    diet.  No loss of hair was noted (de Groot & Spanjers, 1970).


    The feeding studies with rats did not show any deleterious effects.
    The available evidence for the group of modified starches considered
    suggests that caecal enlargement without associated histopathological
    changes is of little toxicological significance.  Several short-term
    studies, a two-year study and a reproduction study in rats are now
    available for evaluation.


    Temporarily not limited.* 

    Further work required by 1973

    Histological report to complete the two-year rat study. 

    Histological report to complete the reproduction study.


    de Groot, A. P. & Spanjers, M. Th. (1970) Report No. R 3096 by
    Centraal Instituut voor Voedingsonderzoek

    Feron, V. J., Til, H. P. & de Groot, A. P. (1961) Report No. R 2329 by
    Centraal Instituut voor Voedingsonderzoek


    * Except for good manufacturing practice.

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

    Leegwater, D. C. (1971) Unpublished report No. R 3431 by Centraal
    Instituut voor Voedingsonderzoek

    Oser, M. (1961) Unpublished report No. 79868 b and c by Food and Drug
    Research Laboratories Inc., submitted by National Starch and Chemical

    Pieters, J. J. L., van Staveren, W. A. & Brinkhuis, B. G. A. M. (1971)
    Unpublished report No. R 3433 by Centraal Instituut voor

    Til, H. P., Spanjers, M. Th., van der Meulen, H. C. & de Groot, A. P.
    (1971a) Report No. R 3363 by Centraal Instituut voor Voedingsonderzoek

    Til, H. P., Spanjers, M. Th., & de Groot, A. P. (1971b) Report No. R
    3403 of Centraal Instituut voor Voedingsonderzoek

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


    See Also:
       Toxicological Abbreviations
       Starch acetate  (FAO Nutrition Meetings Report Series 46a)
       Starch acetate (WHO Food Additives Series 5)
       Starch acetate (WHO Food Additives Series 17)
       STARCH ACETATE (JECFA Evaluation)