Investigation of a multienzyme based amperometric biosensor for determination of sucrose in fruit juices

Determination of sucrose content is one of the most important routinely performed tests for quality control in the beverage industry. Thus, it is rather important to have a fast, simple and sensitive method that can be used for determination of sucrose in sweet-drink processing. The biosensor investigated was based on a thin layer enzyme cell in which glucose oxidase, invertase and mutarotase were immobilized on a protein membrane. Hydrogen peroxide as the product of the consecutive enzyme reaction was detected by amperometric technique. The optimum enzyme composition of invertase, mutarotase, and glucose oxidase for immobilisation was found to be 8498, 672, and 120 U using 2.2 mg BSA as protective agent dissolved in 200 μL phosphate buffer solution. To achieve the best measuring technique, changes in several parameters such as pH value, temperature and flow rate were studied. Having found the optimum conditions, the statistical parameters of the analysis were established. The linear range of the determination was between 1.0 × 10−4 and 2.5 × 10−3 mol/L with a correlation coefficient of 0.99. The sucrose content of several fruit juices was determined with this sensor, and the results were compared with an enzymatic reference method. The correlation between the two sucrose determination methods was found to be 0.97.