Determination of Yeast Assimilable Nitrogen (YAN) in Must

Yeast Assimilable Nitrogen (YAN) is a fundamental parameter to manage correctly the alcoholic fermentation. It is constituted by two components: the inorganic nitrogen present in must as ammonium ion (NH4+) and organic nitrogen constituted by a-amino nitrogen of amino acids.

The CDR WineLab® analytical method for the analysis in wine and must:

  • it is much easier than the method of the formol number generally used and it can be done in autonomous way in winery in real time without using toxic substances and with a simple photometric reading.
  • it allows the determination of the two nitrogen parameters separately, giving the possibility of making any corrections in a way more accurate than the analysis with formol number;
  • The result is not influenced by the presence of proline and hydroxy-proline, amino acids present in must, and not assimilated by yeasts.

Inorganic nitrogen (ammonium) is determined with the enzymatic way whereas organic nitrogen is determined with the o-phthalaldehyde method.

Method

Test Principle

Organic Nitrogen

Chemical reaction involved in the determination of organic nitrogen in the must

The a-amino nitrogen reacts, in presence of N-acetyl-L-cysteine, with the o-phthalaldehyde to form a isoindolic derivative. The difference in absorbance, measured at 366 nm (end-point) is correlated with the amount of organic nitrogen expressed as mg/L of Nitrogen.

 

Inorganic Nitrogen

Chemical reaction involved in the determination of inorganic nitrogen in the must

The ammonium reacts by enzimatic path-way with NADH and α-ketoglutarate to give NAD+ and glutamate. The decrease in absorbance of the solution of NADH, measured at 366 nm (end-point), is proportional to the amount of ammonium nitrogen in the sample.

Calibration Curve

Organic Nitrogen

The calibration curve of CDR WineLab® for the analysis of Yeast Assimilable Nitrogen Organic in must, obtained using reference methods, confirms the excellent linearity of the system over the whole testing range.

Correlation curve with the reference method for the determination of inorganic nitrogen in the must. R² = 0.9972

Inorganic Nitrogen

The calibration curve of WineLab for the inorganic nitrogen analysis, obtained using reference methods, confirms the excellent linearity of the system over the whole testing range.

Correlation curve with the reference method for the determination of inorganic nitrogen in the must. R² = 0.969

 

Reagent test Kits

Measuring range

AnalysesMeasuring rangeResolutionRepeatability

Analyzers for process and quality control in winemaking

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CDR WineLab®

  •  Complete analysis panel, supplied already configured
  • Up to 16 determinations simultaneously
  • Possibility of carrying out analyses of the same sample
  • Integrated printer
  • Full connections (LAN - USB - Bluetooth barcode/QR code reader)
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CDR WineLab® Junior

  • Partial analysis panel, supplied configured with 3 analyses of your choice, implementable
  • Up to 3 determinations simultaneously
  • Wireless connection to external printer
  • USB connections
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