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Structural Changes of Malt Proteins During Boiling
Department of Food Science and Technology, South China University of Technology, Guangzhou 510640, P.R. China
Guangzhou Zhujiang Brewery Group Company, Guangzhou 510315, P.R. China
* Author to whom correspondence should be addressed.
Received: 23 December 2008; in revised form: 3 March 2009 / Accepted: 4 March 2009 / Published: 9 March 2009
Abstract: Changes in the physicochemical properties and structure of proteins derived from two malt varieties (Baudin and Guangmai) during wort boiling were investigated by differential scanning calorimetry, SDS-PAGE, two-dimensional electrophoresis, gel filtration chromatography and circular dichroism spectroscopy. The results showed that both protein content and amino acid composition changed only slightly during boiling, and that boiling might cause a gradual unfolding of protein structures, as indicated by the decrease in surface hydrophobicity and free sulfhydryl content and enthalpy value, as well as reduced α-helix contents and markedly increased random coil contents. It was also found that major component of both worts was a boiling-resistant protein with a molecular mass of 40 kDa, and that according to the two-dimensional electrophoresis and SE-HPLC analyses, a small amount of soluble aggregates might be formed via hydrophobic interactions. It was thus concluded that changes of protein structure caused by boiling that might influence beer quality are largely independent of malt variety.
Keywords: Malt variety; Structure; Wort boiling; Protein unfolding; Two-dimensional electrophoresis
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MDPI and ACS Style
Jin, B.; Li, L.; Liu, G.-Q.; Li, B.; Zhu, Y.-K.; Liao, L.-N. Structural Changes of Malt Proteins During Boiling. Molecules 2009, 14, 1081-1097.
Jin B, Li L, Liu G-Q, Li B, Zhu Y-K, Liao L-N. Structural Changes of Malt Proteins During Boiling. Molecules. 2009; 14(3):1081-1097.
Jin, Bei; Li, Lin; Liu, Guo-Qin; Li, Bing; Zhu, Yu-Kui; Liao, Liao-Ning. 2009. "Structural Changes of Malt Proteins During Boiling." Molecules 14, no. 3: 1081-1097.