Grape rapid methods

Aaron R.T., Davis R.C., Hamdy M.K. and Toledo R.T. Continuous alcohol/malolactic fermentation of grape must in a bioreactor system using immobilized cells. Journal of Rapid Methods and Automation in Microbiology 12 (2) (2004) 127-148. 

Schneider, A., Gerbi, V. and Redoglia, M. (1987) A rapid HPLC method for separation and determination of major acids in grape musts and wines, Am. J. Enol. Vitic., 38(2), 151-155. 

Flamini, R., Dalla Vedova, A., De Rosso, M. and Panighel, A. (2007) A New Sensitive and Selective Method for Analysis of Ochratoxin A in Grape and Wine by direct liquid chromatography/surface activated chemical ionization-tandem mass spectrometry, Rapid Commun. Mass Spectrom. 21(22), 3737-3742. 

A method of ion chromatography with conductivity detection of ions after eluent suppression for analysis of phosphites (phosphonate ion), was developed (Glenn et al., 1990 Ouimette and Coffe, 1988). It is rapid and relatively simple and shows recoveries are higher than 95% and a detection limit in grapes of 0.5-1.0 ppm is reported. 

The FIA-CL methods were developed for measurement of quenching effects of grape seed extracts and polyphenols to ROS. Rapid and precise measurement for OH and O2 could be achieved by the proposed methods (2 or 3 injections/min). 

Figure 8.3. The SACI/MS2 and MS3 fragmentation patterns of OTA and ZAN [M+H]+ ions. (Reprinted from Rapid Communications in Mass Spectrometry 21, Flamini et al., A new sensitive and selective method for analysis of och-ratoxin A in grape and wine by direct liquid chromatography/surface activated chemical ionization-tandem mass spectrometry, p. 3738, Copyright 2007, with permission from John Wiley Sons, Ltd.)...

In the treatment of the vineyard, the active ingredients are deposited on the grape surface. In multiresidue methods, after grinding the sample is homogenized in representative aliquots and 50-100 g are analyzed. With the dissolution of pesticides in the acidic must (pH 3.0-3.7), some active ingredients, such as captan and folpet, may rapidly degrade. Consequently, the timeframe from grinding to extraction... 

Navarro, S., Barha, A., Navarro, G., Vela, N., and Oliva, J., Multiresidue method for the rapid determination — in grapes, must and wine — of fungicides frequently used on vineyards, J. Chromatogr. A, 882, 221-229, 2000. 

The principle of the method consists of rapidly extracting the anthocyanins from the skins, gently at first and then under more extreme conditions, where the diffusion barriers are broken down. Acidity is used as a vector to facilitate extraction. In addition, it is recommended that the grapes should be roughly crushed and the resulting flesh diluted by half. Crushing the seeds also results in partial extraction of their tannins, which is necessary to assess the characteristics of the grapes. The solutions are aqueous, pH 1 (HCl n/10) and pH 3.2 (solution with 5 g/1 tartaric acid neutralized by 1/3). 

Total SulfuT Dioxide After Alkali Treatment The fact that neutral sodium sulfite does not combine with carbonyl compounds and that the hydroxysulfonic acid compounds are rapidly decomposed on treatment with alkali was used by Ripper (1892) as the basis for the determination of total sulfur dioxide in wine by direct iodine titration. In his method, 50 ml. of wine were pipetted into a 200-ml. flask containing 25 ml. of 1 iV KOH. The mixture was shaken and allowed to stand for 10 to 15 minutes. Then 10 ml. of dilute sulfuric acid (1 + 3) were added, and the solution titrated rapidly with 0.02 N iodine solution to a starch end point which persisted for some time. This method was used as the ofiicial direct titration method for wine in the first edition (1919) of the A.O.A.C. Methods of Analysis in the third (1930) edition it was extended to white grape juice, wine, and similar products (1N NaOH or KOH was used and the solution during standing for 15 minutes was occasionally agitated) hut it was dropped from the fourth (1935) and succeeding editions. Ripper compared his method with the Haas distillation method on ten wines whose SO2 content varied from 42 to 1488 mg. per liter and found the difference between the two to vary from 0 to 5 mg. 

Another nutrient important for yeast is the presence of oxygen. Without some initial oxygen, fermentation can slow because Oj is needed for sterol synthesis (Section 1.4.2). Owing to the activity of grape oxidases (Section 7.5.1), the oxygen content of unsulfited musts can rapidly decrease. Aeration or pumping-over musts are methods employed by winemakers to supply additional oxygen to a deficient must, and addition of SO2 at crush can help limit the activity of oxidases. 

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