Toxicological evaluation of some food
    additives including anticaking agents,
    antimicrobials, antioxidants, emulsifiers
    and thickening agents



    WHO FOOD ADDITIVES SERIES NO. 5







    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
    Geneva
    1974

              

    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.


    LACTIC AND FATTY ACID ESTERS OF GLYCEROL

    Explanation

         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.

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

    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 hydrolyzed 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-C14 in 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 14CO2 found in expired air. GLP was metabolized by
    the dog similarly to the rat, some 50% of the administered dose
    appearing as expired 14CO2 over 48 hours (McKennis et al., 1958).

    TOXICOLOGICAL STUDIES

    Acute toxicity

         Two groups of six male rats each were given GLP suspended in
    water by intubation in doses of 8.65 g and 5.75 g/kg bw 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 hydrolyzed in the
    gastrointestinal tract to lactic acid, glycerol and fatty acids. The
    evidence with labelled lactic acid moiety shows that its metabolism in
    the rat is not significantly different from thai of free lactic acid.

         Evaluation is based on the biochemical and metabolic studies.

    EVALUATION

    Estimate of acceptable daily intake for man

         Not limited.*

              

    *    See relevant paragraph in the seventeenth report, pages 10-11.

         As the 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.

         For lactoglycerides containing the DL-(±)-racemate on the
    D-(-)-isomer, the limitation stated for this form should be taken
    into account.

    REFERENCES

    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. et al. (1958) Proc. Soc. exp. Biol., 97, 498

    Treon, J. F. et al. (1962) J. Agric. Food Chem., 10, 111

    See Also:
       Toxicological Abbreviations
       LACTIC AND FATTY ACID ESTERS OF GLYCEROL (JECFA Evaluation)