Safety evaluation of certain food additives - ipcs inchem

FURAN-SUBSTITUTED ALIPHATIC HYDROCARBONS 489
Hydrolysis may occur prior to gastrointestinal absorption. Concentrations
of 27 μl isoamyl furylpropanoate/l (128 μmol/l) and 40 μl ethyl furylpropionate/l
(238 μmol/l) were reported to be completely hydrolysed within 2 h by pancreatin
(Grundschober, 1977). A report that the glycine conjugate of furoic acid
(furoylglycine) was the major metabolite in the urine of rats given a 20 mg oral dose
of furfuryl diacetate is evidence that the acetal ester of furfural was hydrolysed to
acetic acid and furfural, which, in turn, was subsequently oxidized to furoic acid (Paul
et al., 1949). At the same dose level, furfuryl propionate (No. 740) was hydrolysed
to propionic acid and furfuryl alcohol, which was subsequently oxidized to furoic
acid; the methyl ester of 3-furylacrylic acid was hydrolysed to methanol and
furylacrylic acid, which was subsequently oxidized and cleaved to yield furoic acid.
It is anticipated that furfuryl and furoate esters will be hydrolysed to the parent
alcohol and acid, respectively. The parent alcohol, aldehyde and acid are expected
to participate in common pathways of metabolism and excretion.
The hydrolysis of isoamyl 3-(2-furyl)propionate (i.e. isoamyl 3-(2-furan)propionate,
No. 1515) was determined in the duodenal lumen and in the portal blood
of male Dunkin-Hartley guinea-pigs. In an in vitro ester stability study, more than
98% of isoamyl 3-(2-furyl)propionate was hydrolysed within 1 min of incubation at
37 °C in guinea-pig blood, and no free ester was detected after 5 min. Following
injection of 30, 50 and 70 mg/l solutions of isoamyl-3-(2-furyl)propionate in saline
into the duodenal lumen just distal to an occluding ligature at 5 ml/kg body weight
(bw) and 6 ml/min, portal blood samples revealed that no free ester was detected
at 2 or 5 min. Additionally, free ester was not detected in the lumen at the end of
30 min (Pelling et al., 1980). The half-lives (t½) based on loss of the parent ester by
hydrolysis of furfuryl acetate, furfuryl propionate, furfuryl butyrate and furfuryl
isopentanoate when incubated in artificial pancreatic fluid containing pancreatin
were