Document Detail

Amperometric determination of L-lactate based on entrapment of lactate oxidase on a transducer surface with a semi-permeable membrane using a SIRE technology based biosensor. Application: tomato paste and baby food.
MedLine Citation:
PMID:  12033805     Owner:  NLM     Status:  MEDLINE    
Determination of dissolved L-lactate in tomato paste and baby food samples using a SIRE-based (sensors based on injection of the recognition element) biosensor is reported. The measuring principle is based on the use of a small amount of enzyme, which is injected into an internal delivery flow system and held in direct spatial contact with the amperometric transducer by the use of a semipermeable membrane. Measurements are based upon the reversible enzymatic conversion of L-lactate to pyruvate and hydrogen peroxide by lactate oxidase. Differential measurements are performed in which the samples are measured in the presence and absence of enzyme allowing for control over matrix interferences present in crude samples. The linear range investigated for the determination of L-lactate in tomato paste and baby food was 0-0.1 mM using a lactate oxidase concentration of 22 U/mL. Samples were diluted with buffer prior to biosensor measurements. The L-lactate concentrations of the tomato paste and baby food were determined to be 1.02 +/- 0.02 mM and 2.51 +/- 0.10 mM, respectively, using the standard addition method. The repeatability for tomato paste and baby food measurements was 2.5% (RSD, n = 15) and 4.0% (RSD, n = 15) and the reproducibility was 13.0% (RSD, n = 45) and 3.0% (RSD, n = 45), respectively. The concentration of dissolved L-lactate can be used as a measure of freshness in the food industry. All biosensor measurements were compared with measurements from an established spectrophotometric assay (Boehringer Mannheim). It was found that the biosensor had good correlation with the spectrophotometric method. The biosensor gave 12% higher values for the tomato paste measurements and 2.5% higher values for the baby food measurements. However, a distinct advantage of the biosensor is that it can perform L-lactate measurements within 3 minutes, whereas the spectrophotometric assay requires a 35-minute measurement time.
Kirstin Kriz; Linda Kraft; Margareta Krook; Dario Kriz
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of agricultural and food chemistry     Volume:  50     ISSN:  0021-8561     ISO Abbreviation:  J. Agric. Food Chem.     Publication Date:  2002 Jun 
Date Detail:
Created Date:  2002-05-29     Completed Date:  2002-07-12     Revised Date:  2006-04-17    
Medline Journal Info:
Nlm Unique ID:  0374755     Medline TA:  J Agric Food Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3419-24     Citation Subset:  IM    
Chemel AB, Research Park IDEON, SE-223 70 Lund, Sweden.
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MeSH Terms
Biosensing Techniques*
Enzymes, Immobilized*
Food Industry / standards
Fruit / chemistry
Infant Food / analysis*
Lactic Acid / analysis*
Lycopersicon esculentum / chemistry*
Membranes, Artificial
Mixed Function Oxygenases*
Quality Control
Reproducibility of Results
Reg. No./Substance:
0/Enzymes, Immobilized; 0/Membranes, Artificial; 50-21-5/Lactic Acid; EC 1.-/Mixed Function Oxygenases; EC 2-monooxygenase

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