ETHYL LACTATE
Explanation
This substance was evaluated for acceptable daily intake for man
(ADI) by the Joint FAO/WHO Expert Committee on Food Additives in 1967
and 1979 (see Annex I, Refs. 14 and 51). Toxicological monographs were
issued in 1967 and 1979 (see Annex I, Refs. 15 and 52).
Since the previous evaluation, additional data have become
available and are summarized and discussed in the following monograph.
The previously issued monographs have been expanded and are
reproduced in their entirety below.
BIOLOGICAL DATA
BIOCHEMICAL ASPECTS
Substantial evidence has accumulated that simple esters readily
undergo enzymatic hydrolysis into their component acids and alcohols
(FEMA, 1974; Longland et al., 1977; Grundschober, 1977). It can be
presumed that ethyl lactate is readily hydrolysed in the body to ethyl
alcohol and lactic acid, both of which are common food constituents
(Fassett, 1963).
Aqueous solutions of ethyl-L-lactate, containing 1 mg of
ester/ml, were incubated at 37° in a 0.05 N phosphate buffer, pH 7.5,
with or without pancreatin or a porcine small intestinal mucosa
preparation. The chemical hydrolysis of ethyl-L-lactate was found to
be less than 2% during 2 h; with pancreatin less than 7% was
hydrolysed in 1 h and 7-9% in 2 h; with the intestinal mucosa
preparation these figures were 48-56% and 73-86%, respectively
(Leegwater and van Straten, 1979). Thus it is likely that ethyl
lactate is readily hydrolysed in the body to ethyl alcohol and L(+)
lactic acid, both of which are common food constituents.
The metabolic fate of ethyl alcohol is well-known (FEMA, 1974)
and lactic acid is, of course, a normal and essential intermediate in
human metabolism (Oser, 1965). The metabolism of lactic acid has been
studied extensively, both in humans and in other mammals (Informatics,
Inc., 1975; FEMA, 1977).
TOXICOLOGICAL STUDIES
Acute toxicity
None available.
Short-term studies
Rat
Ethyl lactate was reportedly a good energy source and enhanced
growth in a group of eight male weanling rats fed a diet containing 5%
of this ester (approximately equivalent to 5 g/kg bw) over a period of
12 days. One of eight animals died during the course of the experiment
(there was no indication of the cause of death). No adverse effects
were observed in the surviving animals (Yoshida et al., 1971).
Long-term studies
None available.
Comments
Previously it was concluded that this substance was probably
hydrolysed in vivo to lactic acid and ethyl alcohol. Data have
become available on in vitro hydrolysis. The temporary allocation of
ethyl alcohol to the group ADI "not specified" for lactic acid has
been extended.
EVALUATION
Estimate of temporary acceptable daily intake for man
Group ADI for lactic acid: "ADI not specified".*,**
FURTHER WORK OR INFORMATION
Required by 1982
An in vivo hydrolysis study.
* 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.
** Temporary.
REFERENCES
Fassett, D.W. In: Patty, F. A., ed., Industrial hygiene and
toxicology, second edition, Interscience, New York and
London, 1963
FEMA. Scientific literature review of aliphatic primary alcohols,
aldehydes, esters, and acids in flavor usage, published by the
National Information Services under Contract with the Food and
Drug Administration, 1974
FEMA. Scientific literature review of propylene glycol, glycerol and
related substances in flavor usage, published by the National
Information Services under Contract with the Food and Drug
Administration, 1977
Grundschober, F. Toxicological assessment of flavouring esters,
Toxicology, 8, 387-390, 1977
Informatics, Inc. Scientific literature reviews on generally
recognized as safe (GRAS) food ingredients. Lactic acid, US Food
and Drug Administration, Washington, D.C., 1975
Leegwater, D. C. & van Straten, S. In vitro study on the hydrolysis
of ethyl-L-lactate by pancreatin and an intestinal mucosa
preparation. Unpublished report from TNO, Zeist, submitted to the
World Health Organization by C.V. Chemie Combinatie Amsterdam
C.C.A. Gorchem, The Netherlands, 1979
Longland, R. C., Shilling, W. H. & Gangolli, S. D. The hydrolysis of
flavouring esters by artificial gastrointestinal juices and rat
tissue preparations, Toxicology. 8, 197-204, 1977
Oser, B. L. Physiological chemistry, McGraw-Hill Book Company, 1965
Yoshida, M., Ikumo, H. & Suzuki, O. Evaluation of available energy of
aliphatic chemicals by rats: an application of bioassay of energy
to monogastric animal, Agr. Biol. Chem., 35(8), 1208-1215,
1971