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.
 CDR KombuchaLab |
 CDR KombuchaLab Junior |
|
|---|---|---|
| Analyses | Kombucha: Alcohol by Volume Total Polyphenols Fermentable Sugars Acetic Acid Gluconic Acid Galacturonic Acid L-Malic Acid Total Lactic Acid Glycerol Yeast Assimilable Nitrogen (YAN) |
Configuration with tailored panel of analyses |
| Simultaneous Sample Analyses | 16 | 3 |
| Multiple Analyses on a Sample |  |
– |
Method
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.
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 (10 packages of 10 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 |
