Wine and must

Alcoholometer. This hydrometer is used in determining the density of aqueous ethyl alcohol solutions the reading in degrees is numerically the same as the percentage of alcohol by volume. The scale known as Tralle gives the percentage by volume. Wine and Must hydrometer relations are given below. 

See also below under Wine and Must Hydrometer. 

Wine and Must Hydrometer. This instrument has three scales. One scale shows readings of 0° to 15° Brix for sugar (see Brix Hydrometer above) another scale from 0° to 15° Tralle is used for sweet wines to indicate the percentage of alcohol by volume and a third scale from 0° to 20° Tralle is used for tart wines to indicate the percentage of alcohol by volume. 

Another study employed a similar RP-HPLC method for the determination of trails- and d.v-rcsvcratrol, catechin, epicatechin, quercetin and rutin in wines and musts. Wine samples were filtered and diluted when necessary and used for analysis without any other pretreatment. Separation was performed in an ODS column (150 X 4 mm i.d. paricle size 5 71m) at ambient temperature. The gradient began with ACN-5 per cent aqueous acetic acid (9 91, v/v) for 0-10 min to 25 75 in 1 min hold for 11 min to 70 30 in 1 min, hold for 5 min. The flow rate was 1 ml/min. Analytes were detected by DAD. Fluorescence detection used 280/315 nm (excitation/emission) for catechin and epicatechin 314/370 nm for fims-resveratrol and 260/370 nm for d.v-rcsvcratrol. Chromatograms of a red wine sample obtained at different... 

Dialysis and ultraflltration have been largely applied to isolate and fractionate food proteins and peptides. To isolate the protein fraction from wine and must samples, different authors used dialysis followed by lyophilization to concentrate the dialyzed samples [106,108,109], Depending on the application, membrane of different material, filtration surface and cut-off, able to fractionate the molecules in function of their molecular size, can be used to remove either proteins and other macromolecules or amino acids and small peptides. 

Amerine, M. A., Ough, C. S., Wine and Must Analysis, Wiley, New York,... 

However, due to the artifacts resulting from oxidation, hydrolysis of esters or ethers, or isomerization of phenolics during pretreatment of wines, as well as due to the low recovery rates of some phenolics, analysis of wine phenolics via direct injection of the filtered wine into the chromatographic column is often selected (80,82-84). For the red wine and musts (80), which were injected directly into the HPLC without sample preparation, a ternary-gradient system was often employed for phenolic compounds. Twenty-two phenolic compounds, including 10 anthocyanins, were analyzed from red wine. The separation of cinnamic acid derivatives (313 nm),... 

Costantini, A., Cersosimo, M., Del Prete, V, Garcia-Moruno, E. (2006). Production of biogenic amines by lactic add bacteria screening by PCR, TLC and HPLC of strains isolated from wine and must. J. Eood Prot., 69, 391-396. 

Other authors reported that no biogenic amine producers were present among naturally occurring O. oeni strains isolated from wine and must (Moreno-Arribas et al. 2003). Constantini et al. (2006) found no 0. oeni among 92 strains able to produce biogenic amines in a broth medium. PCR screening was used by these authors to confirm the absence of the respective decarboxylase genes. 

Herbert, R, Cabrita, M.J., Ratola, N., Laureano, O. Alves, A. (2005). Eree amino adds and biogenic amines in wines and musts from the Alentejo region. Evolution of amines during alcoholic fermentation and relationship with variety, sub-region and vintage. J. Food. Eng., 66, 315-322. 

Determination of Volatile Acidity in Wine and Must (Grape Juice)... 

Determination of L-Malic and L-Lactic Acids in Wines and Musts... 

This method enables the concentrations of glucose and fructose to be determined separately or the sum of their concentrations to be determined in wines and musts. Phosphorylation of glucose and fructose. 

Determination of Free and Total Sulphur Dioxide in Wines and Musts by Dialysis... 

This step involves calibration of the apparatus which will serve as a reference. It consists of analysing the greatest number possible (minimum 50) wines or must samples containing different and accurately known concentrations of each analyte. The concentration points should be uniformly distributed over the probable scale of measure for each analyte. The matrices should mimic as accurately as possible the wines and musts destined for analysis using that particular instrument. For each calibration sample, a measurement is carried out at a maximum number of wavelengths in the infra-red. Multi-linear regression is then carried out on the results which enables the following relationship to be established ... 

For each analyte, 2-10 characteristic wavelengths are selected. The quality of the calibration is then tested using a separate set of reference wine and must samples. 

Determination of Ethanol in Wines and Musts During Fermentation... 

The complexity of matrix effects has another important consequence it is impossible to use synthetic matrices or even samples spiked with the analytes, even for the controls - only natural wines and musts can be applied for this purpose. 

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