Amperometric Biosensor for glucose determination in Apple juice. Analysis of interferences

RISTOFF MARÍA E.; SORRIVAS VIVIANA; SAIDMAN SILVANA B.; LOZANO JORGE E.

Antalya / Turkey

Congreso; 1st International Congress on Food Technology; 2010

The Association of Food Technology, IUFoST

AMPEROMETRIC BIOSENSOR FOR GLUCOSE DETERMINATION IN APPLE JUICE.ANALYSIS OF INTERFERENCESM. E. Ristoff (1), V. Sorrivas (2), S. Saidman (3), J. E. Lozano (1)1) Pilot Plant of Chemical Engineering (PLAPIQUI-UNS CONICET) Bahia Blanca, Argentina2) Center for Science and Technology (UAT-CCT) Bahia Blanca, Argentina3) Institute of Electrochemistry and Corrosion, INIEC,National University of the South, Bahia Blanca, ArgentinaResearch on amperometric biosensors attracts lots of current interest becauseof their potential applications in the food industry. The objective of the presentwork was (i) to determine possible interferences of electro-active compoundsfound in apple juice; and (ii), when the interference was identified, eliminate orreduce it by the appropriate method. Carbon paste biosensors were preparedby hand-mixing glucose oxidase, graphite powder, paraffin, and ferrocene asmediator. Assay conditions were pH, 7; enzyme content, 10%; and appliedvoltage, 0.16V. Optimal working conditions were determined. The dispersionof enzyme in graphite was characterized using scanning electron microscopy(SEM, JEOL 6300F). The scanning electron microscopic (SEM) images weretaken of the graphite surface before and after immobilization. Solutionsof fructose, malic acid, sucrose, starch and ascorbic acid where added tothe assayed buffer solution up to a concentration currently found in applejuice. Results indicate that the addition of fructose, malic acid, sucrose andstarch do not interfere under these working conditions. Contrarily, ascorbicacid is a major interferent at the chosen potential. The reduction of ascorbicacid was performed enzymatically by ascorbate oxidase, previous to glucosedetermination.