Automated Olive Oil Malondialdehyde Determination by Flow Injection
Measurement of malondialdehyde is based on the reaction with 2-thiobarbituric acid (TBA). This reaction is not specific so the term usually used is 2-thiobarbituric acid reacting substances (TBARS). Olive oil samples are injected in a 2.0 x 10-2 M TBA stream and acidified by merging with a 0.10 M CCl3COOH in n-propanol stream. The resulting reaction mixture is diverted to an incubation coil. All ten incubation coils that are immersed in a water-bath at 95 oC are loaded in 5 min. Then, the flow is stopped for 25 minutes. After sample incubation, the reaction mixture is cooled by passing through an ice-bath and the reaction products are measured in the spectrophotometer. The developed method achieves an analysis rate of 20 samples per hour, while samples are incubated for 30 min. The proposed method compares well with a manual method (relative difference 0-6.2% for the analysis of 30 olive oil samples). Click to see the advantages of the method.
Questions and comments to author: Dr C.A. Georgiou, cag@aua.gr Phone: +3010-5294248, fax: +3010-5294265 Chemistry Laboratory, Agricultural University of Athens, Greece