Covalent Protein-Polyphenol Bonding as Initial Steps of Haze Formation in Beer
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Covalent Protein-Polyphenol Bonding as Initial Steps of Haze Formation in Beer. / Jongberg, Sisse; Andersen, Mogens L.; Lund, Marianne N.
In: Journal of the American Society of Brewing Chemists, Vol. 78, No. 2, 2020, p. 153-164.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Covalent Protein-Polyphenol Bonding as Initial Steps of Haze Formation in Beer
AU - Jongberg, Sisse
AU - Andersen, Mogens L.
AU - Lund, Marianne N.
PY - 2020
Y1 - 2020
N2 - Beer subjected to forced aging by five (Medium) or ten (High) heat/chill cycles (60 °C 48 h/0 °C 24 h) showed increased turbidity from 5.4 ± 0.4 EBC units without forced aging to 12.9 ± 0.7 and 48 ± 2 EBC units for Medium and High forced aged beers, respectively. The particle size diameter increased from 100–200 nm to 10–30 µm. The colloidal changes were associated with modifications of the low molecular weight fraction (∼1 kDa), which were found to increase in the soluble part of the beer as identified by size exclusion chromatography. Polyphenol analyses by liquid chromatography and mass spectrometry showed significant losses of gallic acid, hydroxyphenyllactic acid, salicylic acid, chlorogenic acid, vanillic acid, epicatechin, pyrocatechuic acid, ferulic acid, and luteolin during the forced aging, indicating that these phenolic compounds took part in the colloidal changes, proposedly upon polymerization into tannins. Gel electrophoresis coupled with staining by nitroblue tetrazolium indicated polyphenol modification of all proteins and especially LTP1 (lipid transfer protein 1). It is proposed that the di- and tri-hydroxyl phenolic compounds upon oxidation to quinones react with protein nucleophiles of especially LTP1 to generate the initial covalent bonds, which eventually leads to larger insoluble permanent haze particles.
AB - Beer subjected to forced aging by five (Medium) or ten (High) heat/chill cycles (60 °C 48 h/0 °C 24 h) showed increased turbidity from 5.4 ± 0.4 EBC units without forced aging to 12.9 ± 0.7 and 48 ± 2 EBC units for Medium and High forced aged beers, respectively. The particle size diameter increased from 100–200 nm to 10–30 µm. The colloidal changes were associated with modifications of the low molecular weight fraction (∼1 kDa), which were found to increase in the soluble part of the beer as identified by size exclusion chromatography. Polyphenol analyses by liquid chromatography and mass spectrometry showed significant losses of gallic acid, hydroxyphenyllactic acid, salicylic acid, chlorogenic acid, vanillic acid, epicatechin, pyrocatechuic acid, ferulic acid, and luteolin during the forced aging, indicating that these phenolic compounds took part in the colloidal changes, proposedly upon polymerization into tannins. Gel electrophoresis coupled with staining by nitroblue tetrazolium indicated polyphenol modification of all proteins and especially LTP1 (lipid transfer protein 1). It is proposed that the di- and tri-hydroxyl phenolic compounds upon oxidation to quinones react with protein nucleophiles of especially LTP1 to generate the initial covalent bonds, which eventually leads to larger insoluble permanent haze particles.
KW - Beer
KW - covalent bonds
KW - forced aging
KW - haze
KW - protein-polyphenol interactions
U2 - 10.1080/03610470.2019.1705045
DO - 10.1080/03610470.2019.1705045
M3 - Journal article
AN - SCOPUS:85078430391
VL - 78
SP - 153
EP - 164
JO - Journal of the American Society of Brewing Chemists
JF - Journal of the American Society of Brewing Chemists
SN - 0361-0470
IS - 2
ER -
ID: 235854169