Oxidation of polyphenol

Wildenradt, H. L. and Singleton, V. L. (1974). Production of aldehydes as a result of oxidation of polyphenolic compounds and its relation to wine aging. Am.. Enol. Viticult. 25, 119-126. 

Wildenradt, H. L., Singleton V. L. (1974). Production of aldehydes as a result of oxidation of polyphenolic compounds and its relation to wine aging. J. Agric. Food Chem., 25, 119-126. Wroblewski, K., Muhandiram, R., Chakrabartty, A., Bennick, A. (2001). The molecular interaction of human salivary histatins with polyphenolic compounds. Eur. J. Biochem., 268, 4384-4397. 

Clarification of the must in winemaking is made by treatments with silica gel, filtration, centrifugation, or by the use of enzymes. During filtration and centrifugation, oxidation of polyphenols may occur loss of protective colloids occurring with enzymes can promote precipitation of potassium bitartrate affecting the tartaric acid, pH and total acidity data. For determination of organic acids either in skins or in the... 

Browning, a classical symptom of plant disease, has been recognized as being caused by the oxidation of polyphenols. However, this often was considered a passive process in which phenols were allowed to mix with oxidases released from compartmentalization during breakdown of tissues by pathogens. Studies of Verticillium wilt, bacterial blight, and boll rots indicate that phenols and even the oxidases involved in browning may be formed as part of the active defense (62, 65, 88, 91). 

Withering is the key process for the formation of white tea color, and PPO and POD are needed for color development of white tea. However, the best condition for white tea is the slight and slow oxidation of polyphenols under a temperature of less than 30°C. 

Fig. 6.25. Diagram of the various hypothetical channels for the oxidation of polyphenols in the presence of traces of oxygen channel A, formation of a free radical in C2 channel B, formation of an aryloxy free radical (de Freitas,...

Cobalt (II) complexes with Schiff base ligands are well known to activate dioxygen (16-18) and are frequently used to catalyze the oxidation of organic substrates (19) and to mimick mono and dioxygenases (20). This suggests that the Co-catalyzed oxidation of polyphenols could be a good alternative to the incineration of wastewaters rich in polyphenols. Moreover, the toxicity of Co(II) is much lower than that of other metal ions usually employed as oxidation catalysts. 

Integrated UF and EMR system for the treatment of OMW, with oxidation of polyphenols and quinones and their adsorption on chitosan, (adapted fromTurano et al., 2002 and Calabro et al., 2009b). COD, chemical oxygen demand. 

Use of sulphur dioxide. In addition to antimicrobial activity, another use of SO2 in the production of wine is to protect against enzymic oxidation of polyphenolic compounds in the must before fermentation. It also prevents chemical oxidation in the juice and wine during processing and maturation. As the extent of enzymic oxidation is related to the extent of damage to the berries, ideally SO2 should be added when the berry is damaged and the juice is first exposed to air. 

Jinap Selamat M, Bakar J, Saari N (2002) Oxidation of polyphenols in unfermented and partly fermented cocoa beans by cocoa polyphenol oxidase and tyrosinase. J Sci Food Agric 82 559-566... 

The oxidation of tincture of guaiac by hydrogen peroxide to give a blue color is one of the most sensitive tests for the presence of peroxidase. This reaction was discovered in 1855. In subsequent years the distinctive nature of the enzyme was established and preparations were purified on the basis of oxidation of polyphenols. The assay most commonly used determines the Purpurogallinzahl (PZ), or purpurogallin number. This assay involves incubation of the enzyme under arbitrarily defined conditions with pyrogallol and H2O2 (I). At a specified time the reaction is... 

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