VIEW ARTICLE    doi:10.1094/ASBCJ-2010-0411-01

Enhancing the Concentration of 4-Vinylguaiacol in Top-fermented Beers—A Review. Yunqian Cui (1), China-Germany Brewing Technical Service Center, School of Food and Bio-engineering, Shandong Institute of Light Industry, Shandong, China; Xiaohong Cao, College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin, China; Shanshan Li, China-Germany Brewing Technical Service Center, School of Food and Bio-engineering, Shandong Institute of Light Industry, Shandong, China; Leo Thamm, Ganter Brauerei, Freiburg, Germany; and Guangtian Zhou (2), China-Germany Brewing Technical Service Center, School of Food and Bio-engineering, Shandong Institute of Light Industry, Shandong, China. (1) Current address: College of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin, China. (2) Corresponding author. E-mail: <zgt16509@163.com>; Phone: +86-531-88939075; Fax: +86-531-89631191. J. Am. Soc. Brew. Chem. 68(2):77-82, 2010.

Despite being considered undesirable in bottom-fermented beers, 4-vinylguaiacol (4VG) is a well-known aroma compound found in top-fermented beers such as Belgian white (brewed with unmalted wheat), German Weizen, and rauch (brewed with malted wheat). Most of the published reports have investigated the brewing technology used to enhance the concentration of 4VG, but only a few have explored the genetic engineering of yeast strains to increase its content. In fact, expressing the phenylacrylic acid decarboxylase (PAD1) and phenolic acid decarboxylase (PADC) genes is the most efficient way to enhance the concentration of 4VG in top-fermented beers. Accordingly, this review focuses on the cloning and expression of PAD1 and PADC genes and compares the concentrations of 4VG in top-fermented beers brewed with parent and mutant yeasts in laboratory-scale mashing and fermentation experiments. The results indicate that the concentration of 4VG was markedly increased in top-fermented beers brewed with the mutant yeast. Keywords: Genetic engineering, Phenolic acid decarboxylase gene, Phenylacrylic acid decarboxylase gene, Top-fermented beers, 4-Vinylguaiacol

A pesar de ser considerados indeseables en las cervezas de baja fermentación, 4-vinylguaiacol (4VG) es un compuesto aroma muy conocida se encuentra en las cervezas de alta fermentación, tales como blanco belga (elaborada con trigo sin maltear), Alemán Weizen, y rauch (elaborada con trigo malteado). La mayoría de los informes publicados han investigado la tecnología de elaboración utilizados para mejorar la concentración de 4VG, pero sólo unos pocos han explorado la ingeniería genética de cepas de levadura para aumentar su contenido. De hecho, expresando los genes de la decarboxilasa del ácido phenylacrylic (PAD1) y decarboxilasa del ácido fenólico (PADC) es la forma más eficiente de mejorar la concentración de 4VG en cervezas de alta fermentación. Por consiguiente, esta revisión se centra en la clonación y expresión de los genes de PAD1 y PADC y compara las concentraciones de 4VG en cervezas de alta fermentación elaborada con los padres y mutantes levaduras en experimentos a escala de laboratorio de maceración y fermentación. Los resultados indican que la concentración de 4VG se intensificó notablemente en cervezas de alta fermentación elaborada con la levadura mutante. Palabras claves: Cervezas de alta fermentación, Gen de decarboxilasa del ácido fenólico, Gen de decarboxilasa del ácido phenylacrylic, Ingeniería genética, 4-Vinylguaiacol