title: Degradation of white wine haze proteins by Aspergillopepsin I and II during juice flash pasteurization.
abstract: Bentonite is commonly used to remove grape proteins responsible for haze formation in white wines. Proteases potentially represent an alternative to bentonite, but so far none has shown satisfactory activity under winemaking conditions. A promising candidate is AGP, a mixture of Aspergillopepsins I and II.; a food grade, well characterized and inexpensive protease, active at wine pH and at high temperatures (60-80°C). AGP was added to two clarified grape juices with and without heat treatments (75°C, 1min) prior to fermentation. AGP showed some activity at fermentation temperatures (≈20% total protein reduction compared to control wine) and excellent activity when combined with juice heating (≈90% total protein reduction). The more heat stable grape proteins, i.e. those not contributing to wine hazing, were not affected by the treatments and therefore accounted for the remaining 10% of protein still in solution after the treatments. The main physicochemical parameters and sensorial characteristics of wines produced with AGP were not different from controls.
authors.affiliation: The Australian Wine Research Institute, P.O. Box 197, Glen Osmond (Adelaide), SA 5064, Australia. matteo.marangon@awri.com.au
authors.forename: Matteo
authors.initials: M
authors.lastname: Marangon
authors.forename: Steven C
authors.initials: SC
authors.lastname: Van Sluyter
authors.forename: Ella M C
authors.initials: EM
authors.lastname: Robinson
authors.forename: Richard A
authors.initials: RA
authors.lastname: Muhlack
authors.forename: Helen E
authors.initials: HE
authors.lastname: Holt
authors.forename: Paul A
authors.initials: PA
authors.lastname: Haynes
authors.forename: Peter W
authors.initials: PW
authors.lastname: Godden
authors.forename: Paul A
authors.initials: PA
authors.lastname: Smith
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Waters
mesh_terms: D016282:Aspartic Acid Endopeptidases / Q000737:chemistry*; D006801:Humans; D061352:Pasteurization; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D013649:Taste; D027843:Vitis / Q000737:chemistry* / Q000378:metabolism / Q000382:microbiology; D014920:Wine / Q000032:analysis* / Q000382:microbiology; D015003:Yeasts / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D016282:Aspartic Acid Endopeptidases; C029094:aspergillopepsin I; C022442:aspergillopepsin II