title: Circular dichroism and infrared spectroscopic characterization of secondary structure components of protein Z during mashing and boiling processes.
abstract: In beer brewing, protein Z is hypothesized to stabilize beer foam. However, few investigations have revealed the relationship between conformational alterations to protein Z during the brewing process and beer foam. In this report, protein Z from sweet wort was isolated during mashing and boiling processes. Circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) were used to monitor the structural characteristics of protein Z. The results showed that the α-helix and β-sheet content decreased, whereas the content of β-turn and random coil increased. The complex environment rich in polysaccharides may facilitate conformational alterations and modifications to protein Z. Additionally, the formation of extended structural features to protein Z provides access to reactive amino acid side chains that can undergo modifications and the exposure of hydrophobic core regions of the protein. Analyzing structural transformations should provide a deeper understanding of the mechanism of protein Z on maintaining beer foam.
authors.affiliation: State Key Laboratory of Food Science and Technology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Lab of Brewing Science and Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Han
authors.affiliation: State Key Laboratory of Food Science and Technology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Lab of Brewing Science and Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
authors.forename: Jinjing
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Food Science and Technology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Lab of Brewing Science and Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
authors.forename: Yongxian
authors.initials: Y
authors.lastname: Li
authors.affiliation: Lab of Brewing Science and Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Hang
authors.affiliation: Cargill Malt, McGinty Road West, MS 135, Wayzata, MN 55391, USA.
authors.forename: Xiangsheng
authors.initials: X
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Food Science and Technology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China; Lab of Brewing Science and Technology, School of Biotechnology, Jiangnan University, Wuxi 214122, China. Electronic address: liqi@jiangnan.edu.cn.
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D001515:Beer; D001798:Blood Proteins / Q000737:chemistry*; D002942:Circular Dichroism; D005524:Food Technology; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
chemical_list: D000596:Amino Acids; D001798:Blood Proteins; C026080:plasma protein Z
keywords: CD; FTIR; Mashing and boiling processes; Protein Z; Secondary structure