Macrowine 2021
IVES 9 IVES Conference Series 9 Identification of caffeic acid as a major component of Moscatel wine protein sediment

Identification of caffeic acid as a major component of Moscatel wine protein sediment


Proteins play a significant role in the colloidal stability and clarity of white wines [1]. However, under conditions of high temperatures during storage or transportation, the proteins themselves can self-aggregate into light-dispersing particles causing the so-called protein haze [2]. Formation of these unattractive precipitates in bottled wine is a common defect of commercial wines, making them unacceptable for sale [3]. Previous studies identified the presence of phenolic compounds in the natural precipitate of white wine [4], contributing to the hypothesis that these compounds could be involved in the mechanism of protein haze formation. The objective of this study was to isolate and identify the compounds contained in induced wine protein haze precipitate after alkaline hydrolysis. The heat-induced protein precipitate from five liters of white Moscatel of Alexandria wine was subjected to alkaline hydrolysis in 2 M NaOH, 10 mM EDTA and 1% (w/v) L-ascorbic acid following a protocol described elsewhere [5] with some modifications. The alkaline hydrolyzed sample was subjected to liquid-liquid extraction with ethyl acetate and evaporated to dryness. The extract was further fractionated using reversed phase-high performance liquid chromatography-diode array detector (RP-HPLC-DAD). The major compound present was found to be caffeic acid amongst other minor, unidentified compounds. Caffeic acid was identified by UV-vis spectra and the structure validated by 1H nuclear magnetic resonance (NMR). This work corroborates the observation that phenolic compounds, and caffeic acid in particular, may participate in wine protein haze formation since it is the major compound nonprotein compound present in Moscatel wine protein sediment.

References: [1] F.X. Sauvage, B. Bach, M. Moutounet, and A. Vernhet, Food Chemistry, 2010, 118, 26-34. [2] E.J. Waters, W. Wallace, and P.J. Williams, Journal of Agricultural and Food Chemistry, 1992, 40, 1514-1519. [3] G. Tabilo-Munizaga, T.A. Gordon, R. Villalobos-Carvajal, L. Moreno-Osorio, F.N. Salazar, M. Perez-Won, and S. Acuna, Food Chemistry , 2014, 155, 214-220. [4] M. Esteruelas, N. Kontoudakis, M. Gil, M.F. Fort, J.M. Canals, and F. Zamora, Food Research International, 2011, 44, 77-83. [5] Nardini, M., E. Cirillo, F. Natella, and C. Scaccini, Journal of Agricultural and Food Chemistry, 2002, 50, 5735-5741.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster


Ricardo Chagas*, Ana Lourenço, Luísa Carvalho, Ricardo Ferreira, Sara Monteiro


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IVES Conference Series | Macrowine | Macrowine 2016


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