Abstract:
An enzymatic biosensor has been developed using Xanthine Oxidase (XO enzyme as
sensing material for the determination of antioxidant properties of selected herbal teas. The
enzyme was immobilized in a Kappa-Carrageenan membrane on a carbon paste electrode.
The variables concerning the biosensor preparation such as types of tea, amount of Kappa-
Carrageenan membrane, concentration of tea samples, addition of Xanthine solution and tea
samples, and also addition of supporting electrolytes were studied. The antioxidant
properties of the herbal teas were demonstrated by comparing percentage of inhibition of
selected tea samples using the standard 1, 1-diphenyl-2-picrylhydrazyl DPPH free radical
scavenging potential and with the cyclic voltammogtram using the Dropsens biosensor.
Results show that cyclic voltammetry analysis using the Xanthine Oxidase biosensor
produced significant result in comparison with the free radical scavenging activity using
DPPH. Even though the results using biosensor is less accurate compared to standard
method, but it was fairly acceptable.
