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
PROPYLENE GLYCOL ESTERS OF FATTY ACIDS
Chemical description Mixtures of propylene glycol mono- and
di-esters of fatty acids of food fats.
Structural formula
CH3-CH-OR
'
CH2-OR
Where R or R' represents the fatty acid
moiety and R or R' is hydrogen in the
mono-esters.
Definition Propylene glycol esters of fatty acids
are mixtures of the esters of these
fatty acids with propylene glycol.
They are mainly the mono-esters with
some di-esters and the commercial
products will contain mono- and
diglycerides when fats are used for
transesterification with propylene
glycol.
Description Propylene glycol esters are white to
yellowish white beads, or flakes having
a bland odour and taste.
Uses As emulsifier.
The content of propylene glycol in the
commercial products must be indicated on
the label.
Biological Data
Biochemical aspects
Pancreatic lipase hydrolysed 70 per cent. of propylene glycol
monostearate in vitro at 40° in 15 hours (Balls & Matlack, 1938).
Similarly, steapsin hydrolysed 70 per cent. of propylene glycol
distearate (PGDS) in vitro at 30° in 18 hours (Long et al., 1958).
The absorption, metabolism and hydrolysis of PGDS was studied in rats
using isotopically labelled compounds, and found to be similar to
those of the glyceryl stearate esters (Long at al., 1958a; 1958b).
Acute toxicity
No data are available.
Short-term studies
Rat. Six 21-day old rats were fed for 40 days a diet containing
60 per cent. propylene glycol ester. The animals showed no adverse
effect on body-weight gain. On histological examination of the kidneys
no lesions were observed (Lepkovsky et al., 1935).
Long-term studies
No data are available.
Comments
There is evidence that the propylene glycol esters of fatty acids
are hydrolyzed to propylene and fatty acids. Evaluation is based
on the content of propylene glycol, for which an acceptable daily
intake has been established (FAO/WHO, 1964).
Evaluation
Estimate of acceptable daily intakes for man
mg/kg body-weight1
Unconditional acceptance 0-20
Conditional acceptance 20-60
REFERENCES
Balls, A. J. & Matlack, M. B. (1938) Biochem. J., 123, 679
FAO/WHO (1964) FAO Nutrition Meetings Report Series No. 35;
Wld Hlth Org. tech. Rep. Ser ., 281
Lepkovsky, S., Ouer, R.A. & Evans, H.M. (1935) Biochem. J., 108,
431
Long, C. L., Zeitlin, B. R. & Thiesen, R. jr (1958a) Arch.
Biochem.,77, 440
Long, C. L., Domingues, F.J., Studer, V., Lowry, J. R., Zeitlin, B.R.,
Baldwin, R. R. & Thiesen, R. jr (1958b) Arch. Biochem., 77, 428
1 Calculated as propylene glycol; see the Seventh Report of the Joint
FAO/WHO Expert Committee on Food Additives (FAO/WHO, 1964).