Determination of the Gluconic acid in Kombucha

CDR KombuchaLab: the kombucha analysis system to optimize the production process obtaining results in real time.

During fermentation the symbiotic culture of bacteria and yeasts promotes the formation of various organic acids. Of these, gluconic acid plays has a significant impact on the organoleptic level. It is therefore essential to monitor it not only during the fermentation process of the tea but also, and above all, in the finished product in combination with acetic acid.

CDR KombuchaLab: Instruments for the determination of gluconic acid in Kombucha

The instruments are supplied pre-calibrated and ready to use.
The results are expressed according to the reference method.
The methods are simple: there is no need for an equipped laboratory or for specialist personnel.

  CDRKombuchaLab for analysis on Kombucha on pruction line
CDR KombuchaLab
CDRKombuchaLab Junior for analysis on Kombucha on pruction lineCDR KombuchaLab Junior
Analyses Kombucha:
Alcohol by Volume
Total Polyphenols
Fermentable Sugars
Acetic Acid
Total Acidity
Gluconic Acid
Galacturonic Acid
L-Malic Acid
Total Lactic Acid
Yeast Assimilable Nitrogen (YAN)
Configuration with tailored panel of analyses
Simultaneous Sample Analyses 16 3
Multiple Analyses on a Sample si


Test type: End Point.
Time testing: one test 6 minutes
Analysis sessions with multiple samples are possible for up to a maximum of 16 tests for CDR KombuchaLab and 3 tests for CDR KombuchaLab Junior .

Calibration Curve

The calibration curve of the CDR KombuchLab instrument, obtained by comparing the CDR method with the enzymatic method for the determination of gluconic acid, confirmed an excellent linearity of the system over the entire measurement range.

CDR KonbuchaLab Calibration Curve, obtained by comparing the CDR method with the enzymatic method for the determination of acetic acid - R2=0.9959

Test Principle

Gluconic acid is phosphorylated through the action of a suitable enzyme in the presence of ATP. The adduct formed through the action of NAD+ results in the formation of NADH in a 1:1 ratio with the gluconic acid present in the sample. The end point reaction is measured at 366nm and the increase in absorbance is directly proportional to the concentration of gluconic acid.

Reagent test Kits

The reagents are packaged in foil pouches containing 10 tubes useful to perform 10 analyses.

This is the minimum package that allows the use of CDR systems even to those who need to make a few analyses, thus not wasting reagents.

There are also boxes of 100 tests, however, packaged in 10 bags of 10 tubes containing the reagent.

Code *300583: 10 tests

Code *300580: 100 tests

The reagents have a shelf-life of 6 months

Processing Sample

For precise and repeatable analysis, the sample must be degassed with the appropriate ultrasonic bath (code 222062) with the mini-centrifuge (code 222061) to separate the solid particles present in the solution.

Measuring Range

Test Measuring Range Resolution Repeatability
Gluconic Acid [0.1-3 g/L] 0.1 - 3 g/L 0.01 g/L 0.04 g/L
Gluconic Acid [0.05-1.5 g/L] 0.05 - 1.5 g/L 0.01 g/L 0.02 g/L

Reagents developed by CDR S.r.l - Quality System Certified ISO 9001 Ed. 2015 - Certificate n. 9115

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With the CDR system, you can perform your tests in total autonomy

Neither skilled staff nor a dedicated external laboratory is needed to use our systems. CDR FoodLab® optimizes traditional testing methods, making them faster and easier, while guaranteeing accuracy standards in line with the reference methods.

Analytical kit

CDR FoodLab® Analysis Systems use disposable pre-vialed reagents specifically developed by the research laboratories of CDR. The use of pre-vialed reagents and the analytical procedures allow:

  • a sample preparation that is quick and easy, when needed at all;
  • making analytical procedures extremely fast and easy;
  • removing all needs for complex calibration procedures.

Reagents come in aluminum packages containing 10 test tubes each to perform 10 tests (or packages for 100 tests containing 10 single packages of 10 test tubes each).

Just a few steps and results are yielded right away

Just a few steps will suffice to carry out your analysis in a rapid way in total autonomy. The system is composed of both the analyzer based on photometric technology and a kit of low toxicity, pre-vialed reagents, developed by CDR.

CDR FoodLab® is cost-effective because it does not require the use of expensive equipment and does not entail maintenance, assistance or calibration costs.
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