title: Photoproduction of glyoxylic acid in model wine: Impact of sulfur dioxide, caffeic acid, pH and temperature.
abstract: Glyoxylic acid is a tartaric acid degradation product formed in model wine solutions containing iron and its production is greatly increased by exposure to UV-visible light. In this study, the combined effect of sulfur dioxide, caffeic acid, pH and temperature on the light-induced (⩾300nm) production of glyoxylic acid in model wine containing tartaric acid and iron was investigated using a Box-Behnken experimental design and response surface methodology (RSM). Glyoxylic acid produced in the irradiated model wine was present in free and hydrogen sulfite adduct forms and the measured total, free and percentage free glyoxylic acid values were modeled using RSM. Sulfur dioxide significantly decreased the total amount of glyoxylic acid produced, but could not prevent its production, while caffeic acid showed no significant impact. The interaction between pH and temperature was significant, with low pH values and low temperatures giving rise to higher levels of total glyoxylic acid.
authors.affiliation: National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia. Electronic address: pgrant-preece@csu.edu.au.
authors.forename: Paris
authors.initials: P
authors.lastname: Grant-Preece
authors.affiliation: National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia.
authors.forename: Leigh M
authors.initials: LM
authors.lastname: Schmidtke
authors.affiliation: National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia.
authors.forename: Celia
authors.initials: C
authors.lastname: Barril
authors.affiliation: National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Clark
mesh_terms: D002109:Caffeic Acids / Q000494:pharmacology*; D006038:Glyoxylates / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D008027:Light; D013447:Sulfites; D013458:Sulfur Dioxide / Q000494:pharmacology*; D013644:Tartrates / Q000378:metabolism; D013696:Temperature; D014920:Wine / Q000032:analysis*
chemical_list: D002109:Caffeic Acids; D006038:Glyoxylates; D013447:Sulfites; D013644:Tartrates; D013458:Sulfur Dioxide; C031150:glyoxylic acid; C042345:hydrogen sulfite; C040048:caffeic acid; C029768:tartaric acid
keywords: Caffeic acid (PubChem CID: 689043); Ethanol (PubChem CID: 702); Glyoxylic acid (PubChem CID: 760); Iron (PubChem CID: 23925); Iron(III) tartrate; Photo-Fenton; Photodegradation; Photooxidation; Sulfur dioxide (PubChem CID: 1119); l-Tartaric acid (PubChem CID: 444305); α-Hydroxysulfonate