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