University of North Florida
Browse the Citations

Contact Info

Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Website: @unf

View Stuart Chalk's profile on LinkedIn


Classification: Food -> soy sauce

Citations 5

"Enzymatic Determinations With Rotating Bioreactors: Determination Of Glutamate In Food Products"
Anal. Chim. Acta 1998 Volume 369, Issue 1-2 Pages 147-155
Chitra Janarthanan and Horacio A. Mottola*

Abstract: The benefits of using rotating bioreactors for online or inline determination in food analyzes are illustrated with the determination of L-glutamate. Two enzymatic approaches have been implemented and samples used to illustrate the approaches included: beef and chicken bouillon cubes, soy sauce, chicken broth, seasoning salt, fruit and vegetable juices, and skim milk. One of the methods uses glutamate dehydrogenase (EC in the main enzymatic reaction and diaphorase (EC in the indicator reaction, which involves NADH and hexacyanoferrate(III). The monitored species, amperometrically detected at a platinum-ring electrode, is the hexacyanoferrate(II) produced by the indicator reaction. The second method utilizes a single enzyme, glutamate oxidase (EC, and amperometric monitoring of a product of the enzymatic reaction, H2O2, also at a platinum-ring electrode. Interference by ascorbate present in some samples is eliminated by inline use of a packed reactor containing ascorbate oxidase (EC The relative merits of both systems when using continuous-flow/stopped-flow/continuous-flow processing are discussed.
Glutamate Amperometry Electrode Interferences Immobilized enzyme Stopped-flow Manifold comparison

"Flow Injection Analysis Of Potassium Using An All-solid-state Potassium-selective Electrode As A Detector"
Talanta 1998 Volume 46, Issue 6 Pages 1293-1297
Shinichi Komaba, Junko Arakawa, Michiko Seyama, Tetsuya Osaka*, Ikuo Satoh and Sadako Nakamura

Abstract: The concentration. of potassium was determined by a combination of flow injection analysis (FIA) with an all-solid-state potassium sensor detection. The all-solid-state potassium-selective electrode possessing long-term potential stability was fabricated by coating an electroactive polypyrrole/poly(4-styrenesulfonate) film electrode with a plasticized poly(vinyl chloride) membrane containing valinomycin. The simple FIA system developed in this lab. demonstrated sensitivity identical to that in the batch system and achieved considerably rapid assay (150 samples h-1). Analyses of soy sauce and control serum samples by this FIA system yielded results in good agreement with those obtained by conventional measurements.
Potassium Electrode Electrode Method comparison Apparatus Detector Reference material

"Approach For Conductometric Flow-injection Analysis Of Salt Content In Food"
Nippon Shokuhin Kagaku Kogaku Kaishi 1985 Volume 33, Issue 1 Pages 61-66
Kiyoshi MATSUMOTO, Koh-ichi ISHIDA, Yutaka OSAJIMA

Abstract: The four-electrode cell system described earlier (Agric. Biol. Chem., 1984, 48, 2211) was applied to enable a.c. conductometric measurement of NaCl in foods (cf. Okayama et al., Anal. Abstr., 1981, 40, 6F40) in a flow-injection system. Because the samples of soy and Worcestershire sauce had high (12 to 22%) salt content, further sample dilution in a preliminary mixing coil was required. For injections of aqueous 15% NaCl, the coefficient of variation (n = 10) was 0.22%. Up to 70 samples h-1 could be analyzed and simple detergent cleaning of the system was effective.
Sucrose Conductometry Surfactant

"Application Of Conductometric Flow Injection Analysis To The Salt Contents In Soy Sauce And Worcester Sauce"
Nippon Shokuhin Kagaku Kogaku Kaishi 1986 Volume 33, Issue 6 Pages 450-455
Kiyoshi MATSUMOTO, Koh-ichi ISHIDA, Yutaka OSAJIMA

Abstract: Soy sauce and Worcestershire sauce were diluted with water (1:885 and 1:154, respectively) and NaCl was determined conductometrically. There was no interference from amino-acids or Na benzoate in soy sauce or from acetic acid in Worcestershire sauce. Seventy samples could be analyzed in 1 h. Results agreed well with those by potentiometric argentimetry.
Chloride Conductometry Potentiometry Interferences Method comparison

"Determination Of L-glutamate In Various Commercial Soy Sauce Products Using Flow Injection Analysis With A Modified Electrode"
World J. Microbiol. Biotechnol. 1998 Volume 14, Issue 4 Pages 543-549
Udomsopagit, M. Suphantharika, W. Künnecke, U. Bilitewski and A. Bhumiratana

Abstract: A flow injection analysis (FIA) system with a modified electrode has been developed and optimized for determination of L-glutamate using L-glutamate oxidase (GLOD) (EC GLOD was immobilized on controlled-pore glass using glutaraldehyde. The optimal potential applied on the working electrode was +700 mV against a platinum (Pt) reference electrode. The optimal pH and flow rate of the carrier buffer were 7.4 and 1.5 mL/min, respectively. A modified electrode was integrated into the FIA system in order to eliminate electroactive interference and it was used to determine L-glutamate in 39 samples of Thai commercial soy sauce products. The results obtained were compared with those obtained from enzymatic assay using glutamate dehydrogenase and those from a chromatography assay using an amino acid analyzer. Good correlations were observed amongst these methods. The results indicated that use of an FIA system with a modified electrode was able to eliminate electroactive interference and was applicable to the determination of L-glutamate in food samples. The modified FIA was faster and simpler than the more common methods of enzymatic and chromatography anal.
l-Glutamate Electrode Immobilized enzyme Controlled pore glass Interferences Method comparison