Enzymic method for the spectrophotometric determination of benzoic acid in soy sauce and pickles

A simple spectrophotometric method for the determination of benzoic acid is described. Benzoic acid is measured enzymically through its reaction with benzoate 4-hydroxylase coupled with NADPH and O 2 . The entire enzymic procedure required 20 min to complete. The method greatly simplifies the procedure for benzoic acid determination and permits the routine inspection of a number of samples with very little laboratory equipment. The method was compared with HPLC and satisfactory agreement was achieved.