INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY WORLD HEALTH ORGANIZATIONTOXICOLOGICAL EVALUATION OF SOME FOOD COLOURS, ENZYMES, FLAVOUR, ENHANCERS, THICKENING AGENTS, AND CERTAIN FOOD ADDITIVES

LINK: WHO FOOD ADDITIVES SERIES 6

The evaluations contained in this publication were prepared by the Joint FAO/WHO Expert Committee on Food Additives which met in Rome, 4-13 June 1974¹.

World Health Organization Geneva 1975

¹ Eighteenth Report of the Joint FAO/WHO Expert Committee on Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 557. FAO Nutrition Meetings Report Series, 1974, No. 54.

GLYCEROL ESTERS OF WOOD ROSIN*

BIOLOGICAL DATA

BIOCHEMICAL ASPECTS

No information.

TOXICOLOGICAL STUDIES

Acute toxicity

Substance	Route	LD50 mg/kg bw			References
		Rats	Mice	Guinea-pigs
Pale gum rosin	Oral	7600	4600	4100	Anonymous, 1974
Pale wood rosin	Oral	8400	4100	4100	”  “
Pale tall oil rosin	Oral	7600	4600	4600	”  “

Short-term studies

Rat

(a) Gum Rosin

Groups of 10 male and 10 female rats were fed dietary levels of 0.01, 0.05, 0.2, 1.0 and 5.0% for 90 days. Two similar groups received the stock diet only. No effects were seen upon growth, food intake,

* The natural product rosin is a complex mixture of mutually soluble organic compounds. There are three general methods of producing rosins commercially, these methods (and their products) being: solvent extraction of pure stump wood (wood rosin); tapping of gum from the living tree (gum rosin); separation from tall oil (tall oil rosin). The three rosins, freed of extraneous impurities and refined, differ somewhat quantitatively and in colour but all three may be glycinerated to produce the glycerol ester.

haematology, urinalysis, gross and microscopic histology at levels through 0.2%. At the 5% feeding level all animals died. At 1% the test animals showed an initial lag in weight gain and food consumption during the first two weeks, and liver size was increased at autopsy, no microscopic pathology being seen however (Anonymous, 1960a)

(b) Wood rosin

A study was carried out following a protocol similar to that for gum rosin (see (a) above). Results obtained were similar to those seen for gum rosin (Anonymous, 1960b)

(c) Tall oil rosin

A study was carried out following a protocol similar to that for gum rosin (see (a) above). Results obtained were similar for those seen for gum rosin (Anonymous, 1960c)

(d) Glycerin ester of wood rosin

A study was carried out following a protocol similar to that for gum rosin (see (a) above) using a Hercules product, Ester Gum 8D. No effects were noted upon growth, food intake, haematology, urinalysis, gross and microscopic histology at dietary levels up to and including 1%. At the 5% level depressant effect on growth and food intake was evident and there was a suggestion of increased liver size. No microscopic pathology was seen (Anonymous, 1960d).

Long-term studies

Rat

(a) Gum rosin

Groups of 30 male and 30 female rats were fed dietary levels of 0.05, 0.2 and 1.0% for two years. Two similar control groups received the stock diet only. At the 0.05% and 0.2% feeding levels no effects were seen upon weight gain, food consumption, mortality, haematology and gross and microscopic pathology. At the 1% dietary level some growth depression was noted and at autopsy liver size was increased although no microscopic pathology was noted (Anonymous, 1962d).

(b) Wood rosin

A study was carried out following a protocol similar to that for gum rosin (see (a) above). Results obtained were similar to those seen for gum rosin (Anonymous, 1962e)

(c) Tall oil rosin

A study was carried out following a protocol similar to that for gum rosin (see (a) above). Results obtained were similar to those seen for gum rosin (Anonymous, 1962f).

Dogs

(a) Gum rosin

Groups of three male and three female dogs were fed dietary levels of 0.5 and 1.0 for two years. A control group consisting of six animals of each sex received the basal diet. At the 0.05% level no effects were seen upon weight, food consumption, mortality, haematology, urinalysis, liver and kidney function tests, gross and microscopic histopathology. At the 1% level some increase in liver and kidney size was noted although no pathology was present (Anonymous, 1962a).

(b) Wood rosin

A study was carried out following a protocol similar to that for gum rosin (see (a) above). Results obtained were similar for those seen for gum rosin (Anonymous, 1960b).

(c) Tall oil rosin

A study was carried out following a protocol similar to that for gum rosin (see (a) above). Results obtained were similar to those seen for gum rosin (Anonymous, 1962c).

Comments:

The basic rosins used for production of the glycerol esters are gum rosin, wood rosin and tall oil rosin. Various modifications of these rosins are also used for esterification but not included for evaluation in this monograph. Levels of 0.05%, 0.2%, and 1% in the diet of all basic rosins have been tested adequately in 90 days and two year studies in the rat. The effects noted were essentially growth reduction and increased liver weight without, however, any reported indication of related histopathology. The no-effect level was 0.2%. The two year studies in dogs at dietary levels of 0.05 and 1.0% show  that this species reacts in a manner similarly to the rat. In dogs the effect reported for the 1% level was increased liver weight accompanying pathology. A 90 days’ rat feeding study using a glycerol ester of wood rosin indicates that this ester is qualitatively similar in effect to the parent rosin and suggests a lesser degree of toxicity.

With proper definition of the glycerol ester, the long-term studies with the parent rosins and the cross-over study with the glycerol ester of wood rosin would permit an evaluation.

EVALUATION

It was not possible to arrive at an ADI because of absence of a specification distinguishing glycerol esters of wood rosin from glycerol esters of other rosins.

REFERENCES

Anonymous (1960a) Unpublished report from Industrial BioTest
Laboratories submitted by Hercules Powder Co.

Anonymous (1960b) Unpublished report from Industrial BioTest
Laboratories submitted by Hercules Powder Co.

Anonymous (1960c) Unpublished report from Industrial BioTest
Laboratories submitted by Hercules Powder Co.

Anonymous (1962a) Unpublished report from Industrial BioTest
Laboratories submitted by Hercules Powder Co.

Anonymous (1962b) Unpublished report from Industrial BioTest
Laboratories submitted by Hercules Powder Co.

Anonymous (1962c) Unpublished report from Industrial BioTest
Laboratories submitted by Hercules Powder Co.

Anonymous (1962d) Unpublished report from Industrial BioTest
Laboratories submitted by Hercules Powder Co.

Anonymous (1962e) Unpublished report from Industrial BioTest
Laboratories submitted by Hercules Powder Co.

Anonymous (1962f) Unpublished report from Industrial BioTest
Laboratories submitted by Hercules Powder Co.

Anonymous (1974) Unpublished report submitted by Hercules Powder Co.