The Importance of Free Amino Nitrogen in Wort and Beer
MBAA TQ vol. 42, no. 2, 2005, pp.
113-116 |
VIEW ARTICLE
C. Lekkas (1), G. G. Stewart (1), A. Hill (1), B. Taidi (2), and J. Hodgson
(2). 1. International Centre of Brewing and Distilling (ICBD), Heriot-Watt
University, Riccarton, Edinburgh, EH14 4AS, U.K. 2. Scottish Courage Ltd.,
Technical Centre, 160 Canongate, Edinburgh, EH8 8DD, U.K.
Abstract
Supplementation of wort (15�P containing 30% very-high-maltose [VHM] syrup)
was carried out with five times the natural wort concentration of L-lysine or
L-methionine. Control lager fermentations reached target specific gravity (sp
gr) within 96 h, while wort supplemented with either methionine or lysine
resulted in fermentations that achieved completion within 103 and 48 h,
respectively. The vicinal diketone (VDK) concentration in the fermented wort
with added lysine was greater compared with that generated at the end of control
fermentations. The VDK levels present at the end of fermentations with
supplemented methionine were lower than the levels at the end of the control
fermentations.
Keywords: amino acids, ammonia, fermentation performance, free amino
nitrogen, vicinal diketones, wort supplementations
S�ntesis
Se le a�adi� L-methionina y L-lisina a cinco veces la concentraci�n
normal, a un mosto de 15�P que ten�a 30% de un jarabe VHM (de muy alto
contenido de maltosa). La fermentaci�n (baja) de un control sin los aditivos
alcanz� el Ea deseado en 96 h, mientras que el mosto adicionado de methionina o
lisina tardaron 103 h y 48 h, respectivamente. La concentraci�n de diketonas
vicinales (VDK) en el mosto fermentado con lisina fue mayor que la del mosto de
control, mientras que la con methionina fue menor que la del control.
Palabras claves: amino �cidos, amonio, desempe�o de fermentaci�n,
amino nitr�geno libre, diketones vicinales, suplementos para mosto
