Studies on Analysis of Food Additives (XIIX)

Determination Method of Propionic Acid in Bread by Liquid Column Chromatography with Thermal Detector

Abstract

Propionic acid, which is admitted as a preservative of bread, was separated by steam distillation and determined by liquid column chromatography.
The conditions of liquid column chromatography were as follows:
Apparatus JLC. A Type (Nihon Denshi)
Fixed phase Dowex 1-X8
Eluent 0.1N HCl
Flow rate of eluent 0.6ml/min
Column: for separation 0.8×50cm (40°C)
for detection 0.8×8cm (35°C)
Detector Thermal detector
Sensitivity ±1/100°C or ±3/1000°C (Signal×3)
Chart speed 60mm/hr
The recovery ratio was about 90% in the case of addition experiment to bread, but when propionic acid was previously added before baking, the recovery ratio decreased to about 70%.
It was clarified that the low recovery ratio was not due to the consumption of propionic acid by yeast, but the volatilisation of propionic acid while baking.
The minimum limit concentration of detectable propionic acid was 25ppm.