Wine

Anthocyanins are chemical compounds present in the peel of grapes, whose color changes depending on the acidity of the surrounding environment. They are part of the polyphenol group. In addition to significantly influencing color (depending on the variety of grapes), they protect the grapes from sun radiation. Anthocyanins are scarcely soluble in must and water, but very soluble in the alcohol produced during fermentation. The color of the future wine depends therefore on the degree of maturation of the species of wine and the duration of the peel-juice maceration.In addition, the concentration of polyphenols strongly influences the stability of a red wine during ageing. Therefore, in the case of a red wine, it is important to take into account the phenolic maturity of the grapes when choosing the harvest period.

Anthocyanins Extraction on Grapes

CDR WineLab® the reliable, complete and fast system of wine analyses

The method considered to be the reference method for the determination of phenolic maturity (Glories method) is very time-consuming because it requires a long extraction and sample preparation phase. In addition, it is necessary that the analyses be carried out by an operator specialised in laboratory techniques.The CDR WineLab® method for the determination of Anthocyanins in grapes and therefore of phenolic maturity optimizes the Glories method in order to make it even simpler, faster and more accurate.

Features and benefits of CDR WineLab®

Test type: End Point. Time testing: [uni]. Analysis sessions with multiple samples are possible up to a maximum of 16 tests for CDR WineLab®.<h3 style="margin-left:0px;">Sample treatment</h3>Grapes: simplified must extraction method at pH 1 and pH 3.2. Modified Glories method. Operating extraction technique 1.&nbsp;&nbsp;&nbsp;&nbsp;Select a specific row of vines, from which you will collect a total of 200-300 g of grapes from both sides of the vines according to the random system. For better representativeness of the sample, you should always take subsequent samples of grapes from the same selected row of vines. 2.&nbsp;&nbsp;&nbsp;&nbsp;Grind the sample formed by full grapes in the mixer with code *ACF081 for 1 minute. 3.&nbsp;&nbsp;&nbsp;&nbsp;Take two samples, each of 6 g, and place them in the “disposable” cups provided for this purpose. 4.&nbsp;&nbsp;&nbsp;&nbsp;Add 6 mL of solution A with pH 1 to the first sample. 5.&nbsp;&nbsp;&nbsp;&nbsp;Add 6 mL of solution B with pH 3.2 to the second sample. 6.&nbsp;&nbsp;&nbsp;&nbsp;Cover the cups and wait 30 minutes. Manually mix them a couple of times. 7.&nbsp;&nbsp;&nbsp;&nbsp;Centrifuge the suspensions.

Method

The total Anthocyanins present in the wine in must and grapes, in a very acidic environment and through the action of a concentrated SO₂-based reagent, undergo a discoloration that is measured at 520 nm at end point. This discoloration is directly proportional to the concentration in the sample expressed in mg/L.

Test Principle

The calibration curve of CDR WineLab®, obtained using reference methods (Glories method), confirms the excellent linearity of the system over the whole testing range.

Calibration curve

The calibration curve of the CDR WineLab® instrument for the determination of anthocyanins extracted from grapes, carried out with respect to the Glories reference method. R² = 0.9972

Anthocyanins Extraction on Grapes

Features and benefits of CDR WineLab®

Method

Test Principle

Calibration curve

Reagent test Kits

Measuring range

The Analyzer for for process and quality control in winemaking

CDR WineLab®