Ben Witchell | Plumpton College (original) (raw)

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Papers by Ben Witchell

Research paper thumbnail of Interaction of sulphur dioxide with polyphenols, iron and copper and the effect on oxidation

This study was undertaken to observe the oxidation of polyphenols in different model wine conditi... more This study was undertaken to observe the oxidation of polyphenols in different model wine conditions. Six model wines were kept saturated in oxygen and observed over time for polyphenol depletion, SO 2 reaction and acetaldehyde production. The main model wines (CAT and EPI) contained either the polyphenol (+)-catechin or (-)-epicatechin, SO 2 (100 mg/l), iron (5 mg/l) and copper (0.3 mg/l). The NOMET, NOPOL and NOSO2 model wines were identical except for the absence of metals, polyphenol or sulphur dioxide respectively. The BSA model wine contained benzenesulphinic acid instead of SO 2 . (+)-Catechin and (-)-epicatechin oxidation was observed in CAT and EPI with small amounts of acetaldehyde being produced. Most of the polyphenol was recycled to its constituent form by SO 2 . A comparison with NOSO2, which reacted slowly, demonstrated that the presence of SO 2 accelerated the oxidation of (+)-catechin. In NOMET, the reaction of polyphenols and SO 2 was virtually non-existent and an insignificant amount of acetaldehyde was produced.

Research paper thumbnail of Interaction of sulphur dioxide with polyphenols, iron and copper and the effect on oxidation

This study was undertaken to observe the oxidation of polyphenols in different model wine conditi... more This study was undertaken to observe the oxidation of polyphenols in different model wine conditions. Six model wines were kept saturated in oxygen and observed over time for polyphenol depletion, SO 2 reaction and acetaldehyde production. The main model wines (CAT and EPI) contained either the polyphenol (+)-catechin or (-)-epicatechin, SO 2 (100 mg/l), iron (5 mg/l) and copper (0.3 mg/l). The NOMET, NOPOL and NOSO2 model wines were identical except for the absence of metals, polyphenol or sulphur dioxide respectively. The BSA model wine contained benzenesulphinic acid instead of SO 2 . (+)-Catechin and (-)-epicatechin oxidation was observed in CAT and EPI with small amounts of acetaldehyde being produced. Most of the polyphenol was recycled to its constituent form by SO 2 . A comparison with NOSO2, which reacted slowly, demonstrated that the presence of SO 2 accelerated the oxidation of (+)-catechin. In NOMET, the reaction of polyphenols and SO 2 was virtually non-existent and an insignificant amount of acetaldehyde was produced.

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