Organoleptic polyphenols

Black tea taste is primarily a function of the polyphenols, caffeine, and aroma components. Astringency, an important characteristic of the organoleptic sensation, has been described as consisting of a tangy and a nontangy component.95... 

Wine and beer industry Polyphenols can alter color and flavor of products such as wines. There are many aggressive ways of removing polyphenolic compounds, such as using polyvinylpolypyrrolidone (PVPP) or sulfur dioxide. However, polyphenol removal should be selective to avoid the undesirable alteration of the wine s organoleptic characteristics. For this reason, one option is to use laccases that polymerize the polyphenolic compounds during the wine-making process and then to remove these polymers by clarification (Morozova and others 2007). Several papers have reported that laccase is able to remove undesirable polyphenols and produce stable wines with a good flavor. 

Anthocyanins, flavanols and phenolic acids are the main polyphenols of grapes and grape-derived foods, responsible for their major organoleptic properties. Anthocyanins are directly involved in the color of most red fruits including grapes (7) while flavanols are thought to make an important contribution to the astringency and bitterness of plant derived foods (2,3). 

Although the reactions described above have been shown to modify the properties of polyphenols, they are not sufficient to explain the variations observed in the organoleptic properties (taste and color) of red wine. As well, the relationships existing between structure and taste (e.g. astringency, bitterness) of proanthocyanidins and proanthocyanidin-derived molecules remain to be established. Answers to these questions will require the use of different con lementary approaches, including chemical, sensory and statistical analysis. 

It has been now recognised that die phenolic profile of the foods, along with high intakes of the monounsaturated fatty acids, as oleic acid mainly, confers its health-promoting properties to die Mediterranean diet. In fact, olive oil is the main source of unsaturated acids and polyphenols that constitute a complex mixture in olive fruits and in its derived products. In addition, in O. europaea fruits, phenolic profile and content are important factors to consider in order to evaluate virgin olive oil quality. To remain that they are also partly responsible for autoxidation stability and organoleptic characteristics of olive oil. 

Among organoleptic properties used for quality assessments of wines, astringency deserves particular attention. This complex sensation in the mouth occurs after tasting red wines, which are known for their characteristic high concentration of polyphenolic compounds called tannins. Neither the perception of astringency nor its molecular basis is understood fully, but it is accepted... 

The main organoleptic properties (taste and color) of wine are determined by sugars, acids and polyphenol derivatives. This last group of substances includes quite a lot of structurally diverse molecules, their chemical kinship lies in at least two hydroxyl groups coimected to an aromatic ring, and this is also responsible for... 

Except for specific applications, the requirements for routine polyphenol analysis can be adequately met by the application of a number of tests that are rapidly carried out without the need for elaborate instrumentation. It is difficult to determine or to express the results in terms of concentration, so therefore various indices are used that represent either total polyphenols or different groups of polyphenolic compounds. The tests briefly described below are useful in following the progress of a vinification, in making comparisons between different wines, and in seeking to quantify certain organoleptic properties of wines (notably bitterness and astringency). 

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