FAO Nutrition Meetings
    Report Series No. 40A,B,C
    WHO/Food Add./67.29




    TOXICOLOGICAL EVALUATION OF SOME
    ANTIMICROBIALS, ANTIOXIDANTS, EMULSIFIERS,
    STABILIZERS, FLOUR-TREATMENT AGENTS, ACIDS AND BASES





    The content of this document is the result of the deliberations of the
    Joint FAO/WHO Expert Committee on Food Additives which met at Rome,
    13-20 December, 19651 Geneva, 11-18 October, 19662




                   

    1 Ninth Report of the Joint FAO/WHO Expert Committee on Food
    Additives, FAO Nutrition Meetings Report Series, 1966 No. 40; 
    Wld Hlth Org. techn. Rep. Ser., 1966, 339

    2 Tenth Report of the Joint FAO/WHO Expert Committee on Food
    Additives, FAO Nutrition Meetings Report Series, 1967, in press; 


    Food and Agriculture Organization of the United Nations
    World Health Organization
    1967


    LACTIC ACID AND FATTY ACID ESTERS OF GLYCEROL

    Synonyms                     Lactated mono- and diglycerides; Lactic
                                 acid esters of mono- and diglycerides

    Chemical description         The product consists of mixed glycerol
                                 esters of lactic acid and fatty acids.

    Structural formula           A major component is:

                                 CH2-OR
                                 '
                                 CH-OR'
                                 '
                                 CH2-OR"

                                 Where at least one of R, R' or R"
                                 represent the lactic acid moiety, the
                                 remainder may represent the fatty acid
                                 moiety or hydrogen.

    Description                  Lactated mono- and diglycerides are waxy
                                 solids of variable consistency.

    Uses                         As emulsifier.

    Biological Data

    Biochemical aspects

         Lactoglycerides consist of various esters; in commercial products
    the glycerol lactopalmitate and stearate are the predominant
    components. Almost all toxicological work has been carried out on
    glycerol lactopalmitate (GLP).

         Study of glycerol lactopalmitate (GLP) hydrolysis in the presence
    of hog pancreatic lipase revealed rapid disruption of the ester
    linkage, yielding glycerol, lactic acid and palmitic acid as sole
    reaction products (Treon et al., 1962).

         In another study, no deleterious effect was shown by additional
    GLP or the theoretical intermediate compound glycerol monolactate on
    the in vitro hydrolysis of olive oil by lipase. Hydrolysis, in fact,
    proceeded more, rapidly as shown by enhanced liberation of carboxylic
    acid. On the other hand, glycerol monolactate hydrolysed spontaneously
    and rapidly without enzyme intervention (McKennis et al., 1958).

         14C-labelled GLP (at the lactate-2-C, site) was fed to dogs by
    intubation and the appearance of labelled lactic acid in thoracic duct
    lymph and blood was studied.  Normal levels were found and the
    presence of lactate-2-C14in these fluids showed digestion and

    absorption of GLP to have occurred. The lactate-2-C14 disappeared
    rapidly from lymph and blood. 14C-labelled GLP (at the glycerol-1,3-C
    sites) was metabolized by rats to the same extent as glycerol-1,3-C14
    as shown by the amount of 14C0 2 found in expired air. GLP was
    metabolized by the dog similarly to the rat, some 50 per cent. of the
    administered dose appearing as expired 14CO2 over 48 hours (McKennis
    et al., 1958).

    Acute toxicity

         Two groups of 6 male rats each ware given GLP suspended in water
    by intubation in doses of 8.65 g and 5.75 g/kg body-weight
    respectively. All animals survived without systemic effects other than
    those attributable to mechanical distension. Gross appearance of major
    organs was found to be normal after 14 days (Gongwer, 1959).

    Short-term studies

         Rat. A number of experiments using small numbers of animals
    were done and revealed no toxic effects (Kaunitz, 1958).

    Long-term studies

         Rat. A number of experiments using small numbers of animals
    were done and revealed no toxic effects (Fye & Katz, 1953).

    Comments

         The metabolic studies indicate that the lactic acid and fatty
    acid esters of glycerol are completely hydrolysed in the
    gastrointestinal tract to lactic acid, glycerol and fatty acids. The
    evidence with labelled lactic acid shows that the metabolism of bound
    lactic acid in the rat is not significantly different from that of
    free lactic acid.

         Evaluation is based on the biochemical and metabolic studies. The
    use of this additive is limited by the content of D(-)-lactic acid,
    for which an acceptable daily intake has been established (FAO/WHO,
    1966).

    Evaluation

    Estimate of acceptable daily intake for man

    See mixed tartaric and acetic and fatty acid esters of glycerol, p.
    96.

    REFERENCES

    FAO/WHO (1966) FAO Nutrition Meetings Report Series No. 40; 
    Wld Hlth Org. techn. Rep. Ser.,339, p. 20

    Fye, D. J. & Katz, H. C. (1953) Unpublished report to WHO

    Gongwer, L. E. (1959) Unpublished report to WHO

    Kaunitz, H. (1958) Unpublished report to WHO

    McKennis, H, Turnbull, L. B, Haag, H. R. & Larson, P. S. (1958) 
    Proc. Soc. exp. Biol., 97, 498

    Treon, J. F., Brin, M., Domingues, F. J., Smullin, C. F, Lowry, J. R.
    & Helmick, M. (1962) J. Agric. Food Chem., 10, 111
    

    See Also:
       Toxicological Abbreviations