Simple enzymatic methods for glycerol analysis in commercial beverages

Abstract

Two enzymatic methods using amperometric and colorimetric detection based on two coupled activities (glyceroquinase and glycerol-3-phosphate oxidase) were compared for the glycerol content determination. The enzymatic conversion of glycerol consumes oxygen, which is measured amperometrically in a Clark-type electrode and correlated with the glycerol concentration. In addition to the enzymatic-colorimetric method, there is a third enzymatic reaction that can be used to form a coloured compound; this method involves the addition of peroxidase, 4-chlorophenol and 4-aminoantipyrine. The enzymatic methods studied showed good linearity in the range of 4 to 60 mmol L71 glycerol with a detection limit of 1 mmol L71. Studies of glycerol recovery in fortified sugar cane liquor showed a recovery of 98 + 2% for the enzymatic-amperometric method and of 96 + 1% for the enzymatic-colorimetric method. These two methods were applied to the determination of glycerol in beverages and good correlations were found between these methods. © 2013 Taylor & Francis.