69. Circular dichroism and infrared spectroscopic characterization of secondary structure components of protein Z during mashing and boiling processes

Linjiang Zhu (1), Yupeng Han (1), Qi Li (1), Jinjing Wang (1); (1) Jiangnan University, Wu xi, China

Technical Session 20: Mashing, Boiling, & Wort
Wednesday, August 17  •  8:15–9:30 a.m.
Plaza Building, Concourse Level, Governor’s Square 14

In beer brewing, protein Z was supposed to be beneficial to beer foam. Few investigations have revealed the relationships between conformational alteration of protein Z and beer foam. In this work, protein Z was purified and identified during mashing and boiling processes. Circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) were used to monitor the structural characteristics. The results showed that the contents of alpha-helices and beta-sheets of protein Z decreased and the contents of beta-turns and random coils increased. The complex environment rich in polysaccharides might lead to the conformational alteration and modifications. Meanwhile, the extended structural features of protein Z provided more amino acid residues for modifications and exposed more intra-hydrophobic regions. Analyzing the structural transformations of protein Z provides a deeper understanding of the mechanism of protein Z in maintaining beer foam.

Linjiang Zhu received a Ph.D. degree in microbiology from the Institute of Microbiology, Chinese Academy of Sciences in Beijing, China. He began work in Jiangnan University in August 2012 as a lecturer. He is also a researcher in the Laboratory of Brewing Sciences and Technology of Jiangnan University. His research interests include brewing technology and traditionally fermented foods.