RESOLUTION OIV-OENO 675D-2022

SPECIFIC MONOGRAPHS FOR PROFISETINIDINS/PROROBITENIDINS

THE GENERAL ASSEMBLY,

IN VIEW OF Article 2, paragraph 2 iv of the Agreement of 3 April 2001 establishing the International Organisation of Vine and Wine,

CONSIDERING the work of the “Specifications of Oenological Products” Expert Group,

CONSIDERING the resolution OIV-OENO 624-2022 “Update to the monograph on oenological tannins” which describes a general monograph,

CONSIDERING the need to set up specific monographs for each family of tannins,

DECIDES, at the proposal of Commission II “Oenology”, to add the monograph COEI-1-PROFIS to the International Oenological Codex:

OENOLOGICAL TANNINS

Specific monograph for oenological tannins containing profisetinidins/prorobitenidins

Profisetinidins/prorobitenidins are a sub-class of condensed (or proanthocyanic) tannins. Tannins from the quebracho and acacia spp. tree are included in this sub-class.

1.      Method for the determination of sub-class affiliations

1.1.      Characterisation by high-performance liquid chromatography (HPLC)

1.1.1.     Principle

This method is designed to verify the presence of characteristic components of condensed tannins of the profisetinidin/prorobitenidin sub-group and measure their total concentration. It is applicable to preparations of oenological tannins that are declared as pure and thus as not containing tannins with small masses from different families or sub-families (or classes).

1.1.2.     Reagents, material and apparatus

1.1.2.1.   Reagents

(+)-catechin, CAS No. 154-23-4

Ultrafiltered water (resistivity: 18.3 MΩ·cm)

Water (HPLC quality)

Methanol (HPLC quality)

Formic acid (HPLC quality)

1.1.2.2.   Materials

100-mL borosilicate-glass flask

Filters with 0.45 μm pore size diameter

Plastic 1-mL syringe

1.1.2.3.   Apparatus

Technical balance with precision of 0.01 g

Analytical balance with precision of 0.1 mg

Class-A volumetric glassware

Mass chromatographic system with spectrometry detection composed of:

• Gradient pump for binary or quaternary mix
• Injector fitted with a loop of 10 μL
• Spectrophotometric detector at 280 nm fixe wavelength
• Column Eclipse Plus C-18 (for example): 2.1 x 100 mm, 1.8 µm particle size
• ESI-SIM (Single Ion Monitoring mode via Electro Spray Ionisation) ionisation source
• Mass spectrometer detector: quadrupole time of flight (Q-TOF)

1.1.3.     Preparation of samples and standards

Samples: weigh approximately 0.5 g of oenological tannins on the analytical balance and make a note of the weight. Dissolve the oenological tannins in 100 mL of ultrafiltered water in a 100-mL borosilicate-glass flask and mix well.

Preparation of standard solutions: put 10 mg of (+)-catechin in solution into 50 mL of ultrafiltered water, corresponding to a 200 mg/L concentration. Then carry out dilutions in ultrafiltered water to obtain 5, 10, 20, 40, 60, 80 and 100 mg/L concentrations.

Solvent A: water (HPLC quality) containing 0.1% of formic acid.

Solvent B: methanol containing 0.1% of formic acid.

1.1.4.     Procedure

The sample solutions and standard solutions are filtered on 0.45 µm (pore size diameter) filters and analysed by chromatography under the following conditions given by way of example:

Injected volume: 10 μL of sample solution or standard solution of (+)-catechin

Detection at 280 nm

Composition of elution gradient: (time, % of solvent A)

0min, 99.0%; 0.5 min, 94.0%; 20 min, 50.0%; 25 min, 0.0%; 32 min, 94.0% and 10 min for equilibrium.

Flow rate: 0.3 mL/min

Quantification and detection of the characteristic components of condensed tannins from the profisetinidin/prorobitenidin sub-group or sub-class according to the ESI-SIM scan and Q-ToF detection (for example).

Table 1: Example chemical formulas and m/z of the different profisetinidins/prorobitenidins (for the quebracho tree)

Compound	Chemical formula	m/z
(+)-catechin	C15H14O6	290.1
(-)-epicatechin	C15H14O6	290.1
Catechin-fisetinidol dimers	C30H26O11	562.1
Catechin-fisetinidol trimers	C45H38O16	834.2
Catechin-fisetinidol tetramers	C60H50O21	1106.3

Table 2: Example chemical formulas and m/z of the different profisetinidins/prorobitenidins (for the acacia tree)

Compound	Chemical formula	m/z
(+)-catechin	C15H14O6	290.1
(-)-epicatechin	C15H14O6	290.1
(-)-epicatechin-3-O-gallate	C22H18O10	442.4
Fisetinidol-gallocatechin dimers	C30H26O12	578.1
Robinetinidol-catechin dimers	C30H26O12	578.1
Chalcan-flavan dimers (gambiriin)	C30H28O12	580.1
Catechine-fisetinidol-robinetinidol or gallocatechin-fisetinidol-fisetinidol trimers	C45H58O17	850.2
Robinetinidol-robinetinidol-catechin or gallocatechin-fisetinidol-robinetinidol trimers	C45H38O17	866.2

Figure 1: Example ESI-SIM scan of quebracho tree