Rapid assay of choline in foods using microwave hydrolysis and a choline biosensor

A fast procedure for the determination of choline in food was developed by coupling a microwave hydrolysis procedure with an O(2)/choline oxidase-based electrochemical biosensor. Time and temperature were varied to select the best conditions for the microwave hydrolysis. Results have been compared with those found by the traditional method, constituted by hydrolysis at 70 degrees C followed by enzymatic-colorimetric assay. Data obtained by the biosensor method correlated well with the enzymatic-colorimetric assay (R(2) = 0.998). Microwave versus traditional hydrolysis gave a good correlation both with the colorimetric and with biosensor procedures with a relative error below 6%. The method is sensitive and selective enough to be used for a wide variety of food items reducing remarkably the analysis time.