FAO Nutrition Meetings
    Resort Series No. 44A
    WHO/Food Add./68.33


    Geneva, 21-28 August 1967

    The Eleventh Report of the Joint FAO/WHO Expert Committee on Food
    Additives is published as FAO Nutrition Meetings Report Series,
    1967, No. 44; Wld Hlth Org. techn. Rep. Ser., 1968, 383. This
    Report contains general considerations, including the principles
    adopted for the evaluation, and a summary of the results of the
    evaluations of a number of food additives. Additional information,
    such as biological data and a toxicological evaluation, considered at
    that meeting, is to be found in this document.

    Food and Agriculture Organization of the United Nations
    World Health Organization


    Chemical name                 gamma-Undecalactone

    Empirical formula             C11H20O2

    Structural formula            CH3(CH2)6CHCH2CH2
                                           '    '
                                           O -- C = O

    Molecular weight              184.28

    Definition                    Gamma-Undecalactone contains not less
                                  than 97 per cent. C11H20O2.

    Description                   A colourless to yellow liquid having a
                                  strong fruity odour suggestive of peach,
                                  particularly upon dilution.

    Biological Data

    Biochemical aspects

         This lactose was found to be fairly resistant to ring-opening in
    in vitro experiments using pancreatin or whole rat liver
    homogenates. Only 30-70 per cent. was hydrolysed (Oser, 1967).

    Acute toxicity


    Animal      Route       LD50               Reference

    Rat         oral        18 500             Jenner et al., 1964

    Feeding 13-115 mg per animal of gamma-undecalactone to rats for 5-9
    days was said to produce fatty infiltration of liver parenchymal cells
    (Shillinger, 1950).

    Short-term studies

         Rat. In a 12-week feeding study on 15 males and 15 females,
    using mixed compounds, slight growth and food efficiency depression
    was noted at the 42.7 mg/kg/day level (Oser, 1967). Groups of 15 males
    and 15 females were fed the lactose in their diet at 0 or 15.5
    mg/kg/day for 90 days. No adverse effects were noted (Oser, 1967).

    Long-term studies

         Rat. Groups of 20 males and 20 females were fed diets
    containing 0, 0.1 and 0.5 per cent. undecalactone for 2 years. No
    adverse effects were observed (Baer & Griepentrog, 1967).


         The long-term study in rats compensates for the scanty
    information on the metabolic fate of this compound and the evaluation
    is based on this. Nevertheless, metabolic studies are desirable as
    only one species has been investigated. Further studies in other
    species are also desirable.


    Level causing no toxicological effect

         Rat. 0.5 per cent. (= 5000 ppm) in the diet, equivalent to 250
    mg/kg body-weight/day.

    Estimate of acceptable daily intake for man

                                         mg/kg body-weight

         Unconditional acceptance             0-1.25


    Baer, F. & Griepentrog, F. (1967) Med. Ehrnährung, 8, 344

    Jenner, P. M., Hagan, E. C., Taylor, J. M., Cook, E. L. & Fitzhugh, O.
    G. (1964) Fd Cosmet. Toxicol., 2, 327

    Oser,  B. L., Carson, S. & Oser, M. (1965) Fd Cosmet. Toxicol., 3,

    Oser, B. L. (1967) Unpublished report

    Shillinger, J. I. (1950) Gig. i San., 3, 37

    See Also:
       Toxicological Abbreviations