Improvement of distillation and extraction conditions for analysis of propionic acid in bakery products

Abstract

Propionates including propionic acid, sodium propionate and calcium propionate have been permitted in Korea to prevent rope and growth of mold in bakery products. Steam distillation, ion exchange chromatography and successive gas chromatography have been taken as an official method to analyze propionic acid in foods. Recovery of propionate in bakery products has been reported as 50-60%, which is relatively low. In this study, less effective ion exchange chromatography was omitted. Better recovery of propionic acid was achieved by adjusting distillation conditions using 20% of phosphoric acid and 300 mL distillate volume. Well defined extraction conditions with salt resulted in 80-90% of propionic acid recovery in bakery products. The improved analytical method gave consistent recovery (80-90%) of propionic acid when various bakery products were analyzed.