The symbiotic culture of acetic and yeast bacteria immersed in the sweetened tea infusion triggers an alcoholic fermentation. This fermentation can be favoured by the presence of assimilable nitrogen (organic and inorganic) which can be added before fermentation starts. The quantity of assimilable nitrogen can also be controlled during the fermentation process itself in order to guarantee a complete evolution of the fermentation avoiding undesired organoleptic deviations in the finished product.
CDR KombuchaLab: Instruments for the determination of YAN 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 Fermentable Sugars Total Lactic Acid Acetic Acid Yeast Assimilable Nitrogen (YAN) Gluconic Acid Total Polyphenols |
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 4 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 KombuchaLab instrument, carried out using the known concentration of isoleucine for the organic nitrogen and ammonium chloride for inorganic nitrogen, confirmed an excellent linearity of the system over the entire measurement range.
Test Principle
Organic nitrogen (α – amino nitrogen) and inorganic nitrogen (ammonium ion) are determined separately. In the presence of ammonium and NADH the glutamate dehydrogenase (Gl-DH) reacts with α-keto glutarate to form L-glutamic acid and NAD+. The decrease in absorbance, measured at 366 nm (end-point), of the NADH solution is proportional to the quantity of Inorganic Nitrogen present in the sample expressed in mg of N/L. The Organic Nitrogen (α-amino) reacts in the presence of N-acetyl-L-cysteine with the o-phthalaldehyde forming an isoindolic derivative. The difference in absorbance, measured at 366 nm (end-point) is correlated with the quantity of organic nitrogen expressed in mg of N/L.
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. *300430: 10 tests Organic Nitrogen (*300440) + 10 test Inorganic Nitrogen (*300445)
Code. *300430: 100 tests (10 packages of Code. *300430)
The reagents have a shelf-life of 6 months
Processing Sample
For precise and repeatable analysis, the sample must be degassed with the appropriate ultrasound 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 |
|---|---|---|---|
| Inorganic Nitrogen | 30 – 300 mg/L | 1 mg/L | 5 mg/L |
| Organic Nitrogen | 30 – 300 mg/L | 1 mg/L | 5 mg/L |
