Toxicological evaluation of some food colours, thickening
    agents, and certain other substancse


    The evaluations contained in this publication were prepared
    by the Joint FAO/WHO Expert Committee on Food Additives which
    met in Geneva, 14-23 April 19751

    World Health Organization, Geneva 1975

    1 Nineteenth Report of the Joint FAO/WHO Expert Committee on Food
    Additives, Wld Hlth Org. techn. Rep. Ser., 1975, No. 576;
    FAO Nutrition Meetings Report Series, 1975, No. 55.

    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. 55A

    ISBN 92 4 166008 2

    (C) FAO and WHO 1975




         Numerous studies have shown that triacetin is rapidly hydrolysed
    in vitro by all tissues of the organism including the gastro-
    intestinal tract (Bach & Metais, 1970). This property has been
    utilized for the estimation of tissue esterase concentrations by
    employing triacetin as enzyme substrate (Gomori, 1945; Archibald,
    1946) and has been confirmed in studies comparing lipase and esterase
    activities, the latter acting far more rapidly and especially the
    shorter the fatty acid chain length (Desnuelle, 1961; Desnuelle &
    Savary, 1963; Entressaugles et al., 1961; Greenberger et al., 1966;
    Isselbacher, 1966; Sampugna et al., 1967). Tissue esterases are active
    in combination with acetokinase of Lipman (acetyl CoA synthetase) at
    the cellular level especially in hepatic and cardiac tissue. Triacetin
    is more rapidly absorbed from the gastro-intestinal tract in three
    hours than the other fats tested (Deuel & Hallman, 1940). Triacetin
    has been shown to be a source of liver glycogen (Deuel et al., 1937)
    and when fed in amounts equal in caloric value to 15% glucose it was
    utilized as efficiently as was glucose (McManus et al., 1943). The
    rate of hydrolysis by pancreatic lipase in vitro is increased by
    surface active agents (Nishida, 1957).


    Acute toxicity

    Species     Route           LD50             Reference
                           mg/kg body weight

    Mouse       S.c.           2 670             Spector, 1956
                I.p.           1 400-1 700       Gast, 1963

    Rat         S.c.           3 250             Spector, 1956


         Although no formal short and long-term studies are available, it
    is reasonable to conclude that triacetin is metabolized like other
    fats in food and to take this into account for evaluation as well as
    its ready hydrolysis by non-specific tissue esterases.


    Estimate of acceptable daily intake for man

         Acceptable daily intake not specified.*


    Archibald, R. M. (1946) The determination of lipase activity,
         J. biol. Chem., 165, 443

    Bach, A. & Metais, P. (1970) Graisses à chaînes nes courtes et
         moyennes: aspects physiologiques, biochimiques, nutritionnels et
         thérapeutiques, Ann. Nutr. Alim., 24, 75-144

    Desnuelle, P. (1961) Pancreatic lipase, Advanc. enzymol., 23, 129

    Desnuelle, P. & Savary, P. (1963) Specificities of lipases, J. Lip.
         Res., 4, 369-384

    Deuel, H. J., jr, Butts, J. S., Blunden, H., Cutler, C. H. & Knott, L.
         (1937) Studies on ketosis. IX. Glycogen formation from various
         purified and natural fats, J. biol. Chem., 117, 119

    Deuel, J. H., jr & Hallman, L. (1940) The rate of absorption of
         synthetic triglycerides in the rat, J. Nutr., 20, 227-232

    Entressaugles, B., Pasero, L., Savary, P., Sarda, L. & Desnuelle, P.
         (1961) The influence of the nature of the acid substituents in
         glycerides upon the rate of hydrolysis by pancreatic lipase,
         Bull. Soc. Chim. biol., 43, 581-591

    Gast, J. H. (1963) Some toxicity studies with triacetin, Fed. Proc.,
         22, 368

    Gomori, G. (1945) The microtechnical demonstration of sites of lipase
         activity, Proc. Soc. Exp. Biol. Med., 58, 362


    *    The statement "ADI not specified" means that, on the basis of the
    available data (toxicological, biochemical, and other), the total
    daily intake of the substance arising from its use or uses at the
    levels necessary to achieve the desired effect and from its acceptable
    background in food, does not, in the opinion of the Committee,
    represent a hazard to health. For this reason, and for the reasons
    stated in individual evaluations, the establishment of an acceptable
    daily intake (ADI) in mg/kg bw is not deemed necessary.

    Greenberger, N.J., Rodgers, J. B. & Isselbacher, K. J. (1966)
         Absorption of medium and long chain triglycerides: factors
         influencing their hydrolysis and transport, J. Clin. Invest.,
         45, 217-227

    McManus, T. B., Bender, C. B. & Garrett, O. F. (1943) A comparison of
         acetic acid fed in form of triacetin with glucose as a nutrient
         in feeds, J. Dairy Sci., 26, 13-23

    Nishida, M. (1957) Hydrolysis of solubilized esters in pancreatic
         lipase. IV. Yakugaku Zasshi, 77, 1141-1145

    Sampugna, J., Quinn, J. G., Pitas, R. E., Carpenter, D. L. & Jensen,
         R. G. (1967) Digestion of butyrate glycerides by pancreatic
         lipase, Lipids, 2, 397-402

    Spector, W. (1956) Handbook of Toxicology. Acute toxicities, Vol. 1,

    See Also:
       Toxicological Abbreviations
       Triacetin (ICSC)
       TRIACETIN (JECFA Evaluation)