title: Haze activity of different barley trypsin inhibitors of the chloroform/methanol type (BTI-CMe).
abstract: Our previous study found that the critical protein in SE (silica eluted) proteins is BTI-CMe, and assumed that SE-ve malt for brewing may improve the haze stability in beer. In this study, we investigated the difference in gene sequence and corresponding amino acid sequence of BTI-CMe between SE+ve and SE-ve types. The results showed that there were 7 amino acid differences between Yerong (SE-ve) and Franklin (SE+ve). Two types BTI-CMe were expressed in vitro and purified successfully. By adding the purified BTI-CMe into commercial beer, we found that both original turbidity and alcohol chill haze degree of beer were increased. BTI-CMe of SE-ve haplotype showed a lower level of haze formation in beer than SE+ve haplotype. Response surface methodology (RSM) was conducted to determine the relationship between BTI-CMe and tannic acid, and their effects on haze formation. It was found that (1) higher content of BTI-CMe and/or tannic acid in beer would give rise to higher turbidity; (2) there was a significant interaction between BTI-CMe and tannic acid; (3) haze activity disparity of BTI-CMe between two types was significantly and positively correlated with the tannic acid concentration.
authors.affiliation: Agronomy Department, Zhejiang University, Hangzhou 310029, People's Republic of China.
authors.forename: Lingzhen
authors.initials: L
authors.lastname: Ye
authors.affiliation: Agronomy Department, Zhejiang University, Hangzhou 310029, People's Republic of China.
authors.forename: Lu
authors.initials: L
authors.lastname: Huang
authors.affiliation: Agronomy Department, Zhejiang University, Hangzhou 310029, People's Republic of China.
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Agronomy Department, Zhejiang University, Hangzhou 310029, People's Republic of China.
authors.forename: Dezhi
authors.initials: D
authors.lastname: Wu
authors.affiliation: Agronomy Department, Zhejiang University, Hangzhou 310029, People's Republic of China.
authors.forename: Hongliang
authors.initials: H
authors.lastname: Hu
authors.affiliation: Department of Agriculture and Food, Western Australia, 3 Baron-Hay Court, South Perth, Australia.
authors.forename: Chengdao
authors.initials: C
authors.lastname: Li
authors.affiliation: Agronomy Department, Zhejiang University, Hangzhou 310029, People's Republic of China. Electronic address: zhanggp@zju.edu.cn.
authors.forename: Guoping
authors.initials: G
authors.lastname: Zhang
mesh_terms: D002725:Chloroform / Q000737:chemistry*; D001467:Hordeum / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D014361:Trypsin Inhibitors; D002725:Chloroform; D000432:Methanol
keywords: Beer; Haplotypes; Haze; Prokaryotic expression; Response surface methodology (RSM)