title: L-glutamate biosensor for estimation of the taste of tomato specimens.
abstract: An amperometric biosensor has been developed for measurement of Umami, or the taste based on the amount of L-glutamate, in tomato foods. The biosensor is based on an enzyme-mediator system in which L-glutamate oxidase is used for biochemical oxidation of L-glutamate and a tetrafulvalene-tetracyanoquinodimethane (TTF-TCNQ) paste, prepared from the mixture of TTF-TCNQ salt, graphite powder, and silicone oil, serves as the mediator. The limit of detection, calculated by use of a four-parameter logistic model, was 0.05 mmol L(-1), and the limit of quantification was 0.15 mmol L(-1). The correlation coefficient (R2) was 0.990 and the relative standard deviation was no more than 1% (n=5). The response time (tau (95)) was 20-50 s, depending on concentration. The repeatability of the sensor was better than 5% (n=10). The sensor developed was stable for more than ten days.
authors.affiliation: Centre for Chemical Sensors and Chemical Information Technology, ETH Technopark, 8005 Zurich, Switzerland.
authors.forename: Rasa
authors.initials: R
authors.lastname: Pauliukaite
authors.forename: Gleb
authors.initials: G
authors.lastname: Zhylyak
authors.forename: Daniel
authors.initials: D
authors.lastname: Citterio
authors.forename: Ursula E
authors.initials: UE
authors.lastname: Spichiger-Keller
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000032:analysis / Q000378:metabolism; D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry; D004566:Electrodes; D005971:Glutamates / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry; D006571:Heterocyclic Compounds / Q000737:chemistry; D018551:Solanum lycopersicum / Q000737:chemistry*; D009570:Nitriles / Q000737:chemistry; D010084:Oxidation-Reduction; D012827:Silicone Oils / Q000737:chemistry; D013649:Taste / Q000502:physiology*; D013997:Time Factors
chemical_list: D005971:Glutamates; D006571:Heterocyclic Compounds; D009570:Nitriles; D012827:Silicone Oils; C013703:tetracyanoquinodimethane; D006108:Graphite; D000594:Amino Acid Oxidoreductases; C023061:L-glutamate oxidase; C063887:tetrathiafulvalene