WHO FOOD Toxicological evaluation ADDITIVES of certain food SERIES 32 additives and contaminants Prepared by THE FORTY-FIRST MEETING OF THE JOINT FAO/WHO EXPERT COMMITTEE ON FOOD ADDITIVES (JECFA) IPCS International Programme on Chemical Safety World Health Organization Toxicological evaluation WHO FOOD of certain food ADDITIVES additives and contaminants SERIES: 32 Prepared by The forty-first meeting of the Joint FAO/WHO Expert Committee on Food Additives (JECFA) World Health Organization, Geneva, 1993 IPCS - International Programme on Chemical Safety The International Programme on Chemical Safety (IPCS) is a joint venture of the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization. The main objective of the IPCS is to carry out and disseminate evaluations of the effects of chemicals on human health and the quality of the environment. Supporting activities include the development of epidemiological, experimental laboratory, and risk-assessment methods that can enable production of internationally comparable results, and the development of manpower in the field of toxicology. Other activities carried out by the IPCS include the development of know-how for coping with chemical accidents, coordination of laboratory testing and epidemiological studies, and promotion of research on the mechanisms of the biological action of chemicals. ISBN 92 4 166032 5 CONTENTS - Introduction Preface v Monograph Format vii Antioxidants Gallates 3 Flavouring Substances benzyl acetate 27 2-Ethyl-1-hexanol 35 a.-Methylbenzyl alcohol 57 Flavour Enhancers Disodium 5'- guanylate and disodium 5'-inosinate 67 Food Colours Carotenes from natural sources (algal and vegetable) 87 Sweetening Agents Maltitol and maltitol syrup 101 Saccharin and its salts 105 Thickening Agents Konjac flour 137 Processed Eucheuma seaweed 155 Propylene glycol alginate 159 Miscellaneous Substances B-Cyclodextrin 173 Sodium iron EDTA 195 Sucrose acetate isobutyrate 223 Urea 253 Contaminant Chloropropanols 267 Annexes Annex 1 289 Annex 2 295 Annex 3 297 Annex 4 299 Annex 5 303 v PREFACE The monographs contained in this volume were prepared by the forty first Joint FAO/WHO Expert Committee on Food Additives (JECFA), which met in Geneva, Switzerland, from 9 to 18 February 1993. These monographs summarize the safety data on selected food additives and contaminants reviewed by the Committee. The data reviewed in these monographs form the basis for acceptable daily intakes (ADis) established by the Committee. The forty-first report of JECFA will be published by the World Health Organization in the WHO Technical Report Series. The participants in the meeting are listed in Annex 3 of the present publication and a summary of the conclusions of the Committee is included as Annex 4. Specifications established at the forty-first meeting of JECFA will be published in the FAO Food and Nutrition Paper series. These toxicological monographs should be read in conjunction with the specifications and the report. Reports and other documents resulting from previous meetings of the Joint FAO/WHO Expert Committee on Food Additives are listed in Annex 1. JECFA serves as a scientific advisory body to FAO, WHO, their Member States, and the Codex Alimentarius Commission, primarily through the Codex Committee on Food Additives and Contaminants and the Codex Committee on Residues of Veterinary Drugs in Foods, regarding the safety of food additives, residues of veterinary drugs, naturally occurring toxicants, and contaminants in food. Committees serve this function by preparing reports of their meetings and publishing specifications or residues monographs and toxicological monographs, such as those contained in this volume, on substances that they have considered. Many proprietary unpublished reports are referenced in this volume. These were voluntarily submitted to the Committee, generally by producers of the food additives under review, and in many cases these reports represent the only safety data available on these substances. The working papers used by the Committee to develop the monographs in this volume were developed by Temporary Advisers based on all the data that had been submitted, and all these studies were available to the Committee as it made its evaluations and finalized the monographs. From 1972 to 1975 the toxicology monographs prepared by Joint FAO/WHO Expert Committees on Food Additives were published in the WHO Food Additives Series; between 1975 and 1985 this series was available in the form of unpublished WHO documents provided by the Organization upon request. WHO Food Additives Series Volume No. 20, prepared by the twenty-ninth Committee in 1985, through WHO Food Additives Series Volume No. 24, prepared by the thirty third Committee in 1988, were published by the Cambridge University Press. Beginning with WHO Food Additives Series No. 25, prepared by the thirty-fourth Committee, WHO has produced these volumes as priced documents. The preparation and editing of the monographs included in this volume have been made possible through the technical and financial contributions of the Participating Institutions of the International Programme on Chemical Safety (IPCS), which support the activities of JECFA. IPCS is a joint venture of the United Nations Environment Programme, the International Labour Organisation, and the World Health Organization, which is the executing agency. One of the main vi objectives of the IPCS is to carry out and disseminate evaluations of the effects of chemicals on human health and the quality of the environment. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of the organizations participating in the IPCS concerning the legal status of any country, territory, city, or area or its authorities, nor concerning the delimitation of its frontiers or boundaries. The mention of specific companies or of certain manufacturers' products implies neither that they are endorsed nor recommended by those organizations in preference to others of a similar nature that are not mentioned. Any comments or new informatiop. on the biological or toxicological data on the compounds reported in this document should be addressed to: Joint WHO Secretary of the Joint FAO/WHO Expert Committee on Food Additives, International Programme on Chemical Safety, World Health Organization, A venue Appia, 1211 Geneva 27, Switzerland. MONOGRAPH FORMAT Note: Monographs in this document generally follow the format presented below. All monographs may not, however, require the use of each heading, and in some monographs the format has been modified to better present data about several substances. 1. EXPLANATION 2. BIOLOGICAL DATA 2.1 Biochemical aspects 2.1.1 Absorption, distribution and excretion. 2.1.2 Biotransformation 2.1.3 Effects on enzymes and other biochemical parameters 2.2 Toxicological studies 2.2.1 Acute toxicity studies 2.2.2 Short-term toxicity studies 2.2.2.1-2.2.2.X Species tested 2.2.3 Long-term/carcinogenicity studies 2.2.4 Reproduction studies 2.2.5-2.2.X Special studies 2.3 Observations in humans 3. COMMENTS 4. EVALUATION 5. REFERENCES ANTIOXIDANTS GALLATES (PROPYL, OCTYL AND DODECYL) First draft prepared by Dr G.J.A. Speijers and Mrs M.E. van Apeldoorn National Institute of Public Health and Environmental Protection Laboratory for Toxicology Bilthoven, The Netherlands 1. EXPLANATION Propyl, octyl and dodecyl gallates have been evaluated for acceptable daily intake at the third, sixth, eighth, tenth, fifteenth, sixteenth, seventeenth, twentieth, twenty-fourth, and thirtieth meetings of the Committee (Annex 1, references 3, 6, 8, 13, 26, 30, 32, 41, 53 and 73). At the twenty-fourth meeting a group ADI of 0-0.2 mg/kg bw was established, based on the supposed similarity in the biotransformation of these compounds. The Committee used a higher than normal safety factor (250) because of concern for adverse effects shown in reproduction studies. The gallates were again reviewed by the Committee at its thirtieth meeting. Due to lack of adequate data, an ADI was not established for octyl or dodecyl gallate, and more information on the hydrolysis and the biotransformation (including lactating animals) of the different gallates was required. For propyl gallate an ADI of 0-2.5 mg/kg bw was established. Since the last evaluation, additional data have become available. These new data included four-week and 90-day toxicity studies in rats with propyl gallate and in vitro studies on the hydrolysis of the gallates in different tissues. These data are summarized and discussed in this monograph, which also includes all data from previously published monographs. Because this monograph covers the data on propyl, octyl and dodecyl gallates separately, a modified form of the general monograph format has been used. PROPYL GALLATE 2. BIOLOGICAL DATA 2 .1 Biochemical aspects 2.1.1 Absorption, distribution and excretion. No information available. PROPYL, OCTYL AND DODECYL GALLATES 4 2 .1. 2 Biotransformation The available evidence indicates that the gallate esters are hydrolyzed in the body to gallic acid. Most of the gallic acid is converted into 4-0-methyl gallic acid. Free gallic acid or a conjugated derivative of 4-0-methyl gallic acid is excreted in the urine. Conjugation of the 4-0-methyl gallic acid with glucuronic acid was demonstrated (Booth et al., 1959). Detailed metabolic pathways for propyl gallate have been described (Dacre, 1960). In vitro incubations with propyl, octyl and dodecyl gallate were performed using homogenates of liver, mucosa of the small intestine, and contents of caecum/colon as a source of intestinal microflora. The various homogenates were incubated at 37° C with the individual gallate esters. At various time points up to 24 hours, samples were taken and analysed by HPLC in order to determine the concentration of gallic acid and residual ester. From the time-course of gallic acid formation, as well as the disappearance of the specific esters, the rllte of hydrolysis of the three esters was calculated. All test substances were extensively metabolized by the homogenate of the intestinal mucosa, which was demonstrated by the appearance of peaks in the chromatograms. Furthermore, the caecum and colon contents also showed a high metabolic capacity, especially towards propyl gallate. The amount of gallic acid detected in the incubations was always much smaller than the total decrease of the amount of ester. It seems likely that apart from hydrolysis of the ester bond, other biotransformation routes (oxidation and/ or conjugation) are of major importance for all three gallate esters. The three homogenates show quantitatively different structure-activity relationships for the three esters. Homogenates of liver and of contents of caecum and colon metabolize propyl gallate most extensively, followed by octyl or dodecyl gallate. Homogenate of the mucosa of the small intestine shows the highest rates with octyl gallate, lower rates with dodecyl gallate and propyl gallate. For this homogenate, the rate of formation of gallic acid is inversely related to the chain length of the ester (de Bie & van Ommen, 1992). 2.1.3 Effects on enzymes and other biochemical parameters Propyl gallate inhibited liver mixed function oxidase (MFO) and demethylase activity when added at concentrations of 50 to 500 ~-tM to liver microsomal preparations obtained from male Sprague-Dawley rats. Specifically, the compound inhibited benzpyrene hydroxylase activity and demethylase activity with ethyl morphine, aminopyrene or benzphetamine as substrate. No induction ofMFO activity was noted when propyl gallate was injected intraperitoneally at 300 mg/kg bw 24 hours prior to sacrifice and assay. The microsomes from the treated animals