A review of the methods for the most common parameters determined in wine-namely, ethanol, sulfur dioxide, reducing sugars, polyphenols, organic acids, total and volatile acidity, iron, soluble solids, pH, and color-reported in the last 10 years is presented here. The definition of the given parameter, official and usual methods in wineries appear at the beginning of each section, followed by the methods reported in the last decade divided into discontinuous and continuous methods, the latter also are grouped in nonchromatographic and chromatographic methods because of the typical characteristics of each subgroup. A critical comparison between continuous and discontinuous methods for the given parameter ends each section. Tables summarizing the features of the methods and a conclusions section may help users to select the most appropriate method and also to know the state-of-the-art of analytical methods in this area.
Keywords Parameters, Official methods, Usual methods, Non chromatographic methods, Chromatographic methodsWine is a product with a very complex composition. Among the large number of substances found in wine, many are at very low concentrations even though they play a main role in wine characteristics, evolution, and/or quality. A complete analysis of wine is a time-consuming process, but it yields the necessary information for both elaboration of a quality product and conservation under proper conditions. Usually, the number of parameters to be analyzed is simplified as a function of the aim, the commonest being either to know the evolution of the process or to fulfill food laws. The more detailed the analysis is, the better knowledge of the wine is achieved, but a compromise between time and information requirements must be established in order to guarantee a given quality with minimum cost. Therefore, only a few parameters are periodically checked. Between them, the most common are: soluble solids, reducing sugars, alcoholic degree, pH, total and volatile acidity, sulfur dioxide, color, polyphenol index, iron, and organic acids.Most analytical methods for monitoring wine composition recognized by the international community as official methods of analysis are manual methods with high robustness and precision, even though more recent methods may be based on modern automated instrumental techniques. Nevertheless, the manual methods are slow, tedious, and require a high level of human participation. Thus, their application is a balance between the number of parameters required for monitoring wine production, frequency of analysis, and cost of human and material resources. The new faster methods, which usually have the appropriate sensitivity, selectivity, and precision, can circumvent the problem created by the large number of samples to be analyzed in order to guarantee proper monitoring of wine production. In the last 10 years, rapid and high sample throughput methods of analysis have been developed. It is interesting to know the features of these new methods-mainly in terms of accuracy and preci...
