VIEW ARTICLE    DOI: 10.1094/ASBCJ-64-0166

Identification of the Major Proteins in Beer Foam by Mass Spectrometry Following Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis. Junguang Hao, The Key Laboratory of Industrial Biotechnology, Ministry of Education, Southern Yangtze University, Wuxi, Jiangsu, People’s Republic of China and Research Center of Tsingtao Brewery Group, Qingdao, Shandong, People’s Republic of China; Qi Li (1), The Key Laboratory of Industrial Biotechnology, Ministry of Education, Southern Yangtze University, Wuxi, Jiangsu, People’s Republic of China; Jianjun Dong and Junhong Yu, Research Center of Tsingtao Brewery Group, Qingdao, Shandong, People’s Republic of China; Guoxian Gu, The Key Laboratory of Industrial Biotechnology, Ministry of Education, Southern Yangtze University, Wuxi, Jiangsu, People’s Republic of China; Wei Fan, Research Center of Tsingtao Brewery Group, Qingdao, Shandong, People’s Republic of China; and Jian Chen, The Key Laboratory of Industrial Biotechnology, Ministry of Education, Southern Yangtze University, Wuxi, Jiangsu, People’s Republic of China. (1) Corresponding author: Phone: +86.510.5805219; Fax: +86.510.5805219; E-mail: <liqi@sytu.edu.cn> J. Am. Soc. Brew. Chem. 64(3):166-174, 2006. Accepted November 9, 2005.

Previously unknown beer and beer foam proteins of barley origin were identified by tandem mass spectrometry (MS) sequencing after in-gel tryptic digestion. Coomassie blue stained sodium dodecyl sulfate-polyacrylamide gel electrophoresis 40-kDa and 7- to 17-kDa bands were excised for these analyses. In total, there were 30 proteins detected, 21 proteins found in beer, and 24 proteins found in beer foam including the common 15 proteins in beer and 2× foam. Most originated from the bar­ley albumins and were resistant to enzymes during brewing. There were also two hordein-related proteins. The proteins identified enlarge and update the list of proteins related to foam, usually confined to protein Z4, lipid transfer protein 1 (LTP1), and some hordein-derived proteins.

Previamente las proteínas desconocidas de cerveza y espuma de cerveza con origen de cebada fueron identificadas por secuencias de espectrometría de masa en tándem después de una digestión triptica en gel. Bandas de 40-kDa y 7- a 17-kDa de electroforesis en gel polia­crilamida con dodecil sulfato de sodio manchado con azul coomassie fueron suprimidas para este análisis. En total, 30 proteínas fueron detectadas, 21 proteínas fueron encontradas en cerveza, y 24 proteínas fueron encontradas en espuma de cerveza incluyendo las 15 proteínas comunes de cerveza y espuma 2×. La mayoría origino de albúminas de cebada y fueron resistentes a enzimas durante la elaboración de cerveza. También hubo dos proteínas hordeína relacionadas. Las proteínas identi­ficadas agrandan y ponen al día la lista de proteínas relacionadas con la espuma, usualmente confinadas a la proteína Z4, la proteína 1 (LTP1) de transferencia lípida, y unas proteínas hordeína derivadas.