A reliable and reproducible method for the lipase assay in an AOT/isooctane reversed micellar system: Modification of the copper-soap colorimetric method. (1st September 2015)

• Record Type: Journal Article
• Authors: Kwon, Chang Woo; Park, Kyung-Min; Choi, Seung Jun; Chang, Pahn-Shick
• Is Part Of: Food chemistry. Volume 182(2015)
• Page Start: 236
• Page End: 241
• Publication Date: 2015-09-01
• Subjects: Bis(2-ethylhexyl) sodium sulfosuccinate (AOT) -- Copper-soap colorimetric method -- Lipase assay -- Reverse micelles; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2015.02.145
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: The copper-soap method has limitations for the lipase assay in AOT/isooctane reversed micelles. The visible light absorbing properties of the AOT-copper complex caused the interference. To prevent the interference, we modified copper-soap method by AOT extraction step. Acetonitrile was the most suitable solvent for AOT extraction. Abstract: The copper-soap method, which is based on the absorbance of a fatty acid-copper complex at 715 nm, is a widely used colorimetric assay to determine the lipase activity in reversed micellar system. However, the absorbance of the bis(2-ethylhexyl) sodium sulfosuccinate (AOT)-copper complex prevents the use of an AOT/isooctane reversed micellar system. An extraction step was added to the original procedure to remove AOT and eliminate interference from the AOT-copper complex. Among the solvents tested, acetonitrile was determined to be the most suitable because it allows for the generation of a reproducible calibration curve with oleic acid that is independent of the AOT concentrations. Based on the validation data, the modified method, which does not experience interference from the AOT-copper complex, could be a useful method with enhanced accuracy and reproducibility for the lipase assay.