Propanoic Acid Analysis by Acetone Extraction from Bread
2018
Hwang, J.H., Semyung University, Jecheon, Republic of Korea | Shin, D.Y., Filltech Aerosol, Republic of Korea | Oh, C.H., Semyung University, Jecheon, Republic of Korea
The preservative propanoate, such as calcium and sodium propanoate, extends the shelf-life of bread by inhibiting the growth of bread molds quite effectively. Korean regulations on the maximum use level of propanoic acid in bread (2.5 g/kg) is a simple horizontal regulation, not like the European Economic Community, where the vertical regulation to specific bread is also applied. The conventional propanoic acid analysis method consists of onerous pretreatment processes, such as distillation, solvent extraction, etc. In this study, the direct extraction of propanoic acid from bread by acetone (with 1% acetic acid) was evaluated by comparing it with the conventional acidified water extraction followed by diethyl ether partition method. The acetone (with 1% acetic acid) extraction method recovered 110∼117% of propanoic acid from a bread sample spiked with sodium or calcium propanoate. The salt form of propanoate might have dissolved in the intrinsic water in bread, and transformed to the protonated form during the extraction step with the (acidified) acetone. The propanoic acid amounts detected in eight imported breads were within the maximum use level in Korea. The detected level of concentrations (464~2,016 mg/kg) estimated to be varied by the amount ratio of dough (treated with propanoate salts) in the bread. No propanoate was found in four bread samples (as labeled) produced domestically. This simple analysis method could be done within an hour (using GC-FID). The newly developed propanoate analysis method for bread could be used for QA/QC in processing factories and for monitoring the level of exposure for consumers.
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