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.



         These emulsifiers have been evaluated for acceptable daily intake
    by the Joint FAO/WHO Expert Committee on Food Additives (see Annex 1,
    Ref. No. 13) in 1966.

         The previously published monograph has been revised and is
    reproduced in its entirety below.



         The long-chain fatty acids in triglycerides may be replaced with
    one or more acetic acid groups to produce mono- or diacetins
    (acetoglycerides) which are resistant to changes in consistency, heat
    damage and oxidative rancidity (Alfin-Slater et al., 1958; Ambrose &
    Robbins, 1956b). Lipolytic studies in rats showed the presence of
    large amounts of free fatty acids but only traces of free acetic acid
    in the lipids isolated from the stomach after feeding acetoglycerides.
    Ligation of the pylorus indicated a more rapid absorption of the
    acetic acid moiety by the stomach wall than of glycerol and monoacetin
    (Hertnig et al., 1956). Absorption of acetoolein or acetostearin,
    given as 20% of the diet, was studied in groups of 10 adult male rats.
    Acetooleins were better absorbed than acetostearins. Faecal lipid
    estimations showed much greater absorption (i.e. lowest excretion) in
    rats of unsaturated acetoglycerides (acetooleins) than of saturated
    acetoglycerides (acetostearins) (Ambrose & Robbins, 1956b).

         The digestibility coefficients of acetoglycerides fed as 20%
    of the diet to rats varied between 94 and 99% depending on the
    composition of the mixture administered (Ambrose & Robbins, 1956b).
    In another study, groups of 10 male weanling rats were fed diets
    containing 0 or 30% of two different acetostearins for 20 weeks.
    Tissue cholesterol levels (plasma, liver, adrenal) for the 30% level
    were similar to those in rats on a fat-free calorie-restricted diet
    (Coleman et al., 1963).


    Acute toxicity

    Animal     Route     LD50 mg/kg bw         Reference

    Rat        oral            4 000           Ambrose & Robbins, 1956a

         No toxic symptoms were seen in rats after single doses of
    4000 mg/kg bw of acetostearin or acetoolein. Daily i.v. injection of
    80-100 mg acetostearin into rabbits for 15 days caused no apparent ill
    effects and viscera showed no pathological changes. Acetostearin
    cleared completely from the blood plasma within 15 to 30 minutes
    (Ambrose & Robbins, 1956a; Alfin-Slater et al., 1958).

    Short-term studies


         Groups of 10 male weanling rats received diets containing 25% of
    either stearin, olein, diacetostearin or diacetoolein, and additional
    groups received 50% olein or diacetoolein for eight weeks or 15%
    acetoolein for 12 weeks. There was no difference between test and
    control groups with regard to body weight gain, food consumption or
    food efficiency, except for the groups receiving stearins. Only in the
    groups receiving diacetostearin was the coefficient of utilization
    markedly higher. Results of examination of blood and urine were normal
    (Mattson et al., 1956). Studies for seven months on groups of five
    male and 10 female rats using 10% acetostearin in the diet with
    additional supplements of Vitamin E showed improved reproduction
    performance (as measured by litter numbers and pups per litter in four
    successive matings) compared with controls or animals on acetostearin
    alone (Ambrose et al., 1958b).

    Long-term studies


         Six groups of five weanling male rats each were fed diets
    containing 0, 0.25, 0.5, 1, 2 and 4% acetostearin and another four
    groups of rats were fed diets containing 0, 0.25, 0.5 and 1.0%
    acetoolein for 57 weeks. Body weight gain, food intake and mortality
    did not differ from those of the controls. Measurement of relative
    weights of major organs revealed decreased testicular weights at all
    levels of acetoolein and with the 0.25% and 0.5% levels of
    acetostearin. Microscopic examination showed no difference from
    controls except for testicular hypoplasia and suppression of

    spermatogenesis of a variable degrees in all test groups (Ambrose &
    Robbins, 1956a).

         In another experiment, three acetostearins and two acetooleins
    were fed to groups of 10 male and 10 female rats each at 0, 5, 10 and
    20% of their diet. Parental generation animals on 20% acetoglyceride
    were sacrificed after 57 weeks, 86 weeks and 101 weeks. Mortality rate
    was not increased at any dose level up to 57 weeks, but some increase
    occurred in all test groups compared with controls after 86 weeks.
    Body weight gain was slightly depressed at the 20% level. Examination
    of major organs showed consistently reduced testicular weight at the
    20% level of all three acetostearins and at the 5% and 10% levels of
    two acetostearins. Significant liver enlargement was also observed at
    the 20% level of acetostearins but liver glycogen was unaffected. Food
    utilization was decreased by acetostearin more than by acetoolein
    depending on dose. A variety of pathological changes were observed
    with individual acetoglycerides at varying dietary levels, but these
    changes were attributed to imbalance of the test diet with respect to
    vitamin E and essential fatty acids. Fatty tissue changes reminiscent
    of sclerema adiposum neonatorum (foci of foreign body reactions)
    especially near the gut were seen with all acetostearins at 20% level
    but none in the other groups (Ambrose et al., 1958a).


         Acetoglycerides are readily hydrolyzed in the gastrointestinal
    tract and dealt with in the body in a manner similar to other
    glycerides. The digestibility studies are only of limited value since
    the inclusion of materials of this sort in an adequate quantity of
    lipid fat, occurring naturally in the diet, ensures satisfactory
    absorption. Dietary loads of a food additive in excess of 10% are of
    little value in the assessment of safety-in-use as many irrelevant
    effects may occur, such as observed with high dose levels of
    acetostearins. (For example, testicular atrophy due to an increased
    requirement for vitamin E, and foreign body reaction in adipose tissue
    due to overloading with saturated fatty acids.) Evaluation is based on
    the biochemical and metabolic studies because the breakdown products
    are normal dietary constituents.


    Estimate of acceptable daily intake for man

         Not limited.*1,2


    *1   See relevant paragraph in the 17th Report, pp. 10-11.
    *2   As sum of glycerol esters of fatty acids and acetic, citric,
    lactic and tartaric acids, provided that the total food additive
    intake of tartaric acid does not exceed 30 mg/kg.


    Alfin-Slater, R. B. et al. (1958) J. Amer. Oil Chem. Soc., 35, 122

    Ambrose, A. M. & Robbins, D. J. (1956a) J. Amer. Pharm. Ass. Sci.
         Ed., 45, 482

    Ambrose, A. M. & Robbins, D. J. (1956b) J. Nutr., 58, 113

    Ambrose, A. M., Robbins, D. J. & Cox, A. J., jr (1958a) Food Res., 23,

    Ambrose, A. M., Robbins, D. J. & De Eds, F. (1958b) Food Res., 23, 550

    Coleman, R. D., Gayle, L. A. & Alfin-Slater, R. B. (1963) J. Amer. Oil
         Chem. Soc., 40, 737

    Hertnig, D. C. et al. (1956) Fed. Proc., 15, 556

    Mattson, F. H. et al. (1956) J. Nutr., 59, 277

    See Also:
       Toxicological Abbreviations