Effects of Pulses of Higher Temperature on the Development of Enzyme Activity During Malting
F. Toffoli 1, A. Gianinetti 1, 2, A. Cavallero 1, F. Finocchiaro 1 and A. M. Stanca 1
1 Experimental Institute for Cereal Research, Section of Fiorenzuola, s.s. S. Protaso, 302, 29017 Fiorenzuola (PC), Italy.
2 Corresponding author. E-mail: agianinetti@tin.it
J. Inst. Brew. 109(4), 337-341, 2003 | VIEW ARTICLE
ABSTRACT
The increase of temperature at the beginning, in the middle and at the end of malting has been evaluated in terms of quality parameters (malting losses, index of acrospire development, friability, HWE, viscosity, SNR) and enzyme (β-glucanase and α - amylase) development, in a good quality malting barley (Otis) and a higher protein-higher β-glucan content barley used for feed (Extra). A shift from 15 to 20°C at the beginning of malting was shown to increase acrospire development, friability, HWE and SNR and to reduce viscosity, without significantly affecting malting losses. This effect was related to higher β-glucanase and α - amylase activities within each variety. However, the same enzyme activities were not directly related to a better malting quality when the two genotypes were compared. This confirms previous indications that diversity in malting performance between genotypes cannot simply be traced back to differences in enzyme activities; but, indeed, it suggests that, for a defined barley lot, changes in the levels of enzyme activities following different malting procedures may have a direct effect on malt quality.
Key words:
α - Amylase activity, β-glucanase activity, malting
temperature, quality parameters.
Publication no. G-2003-1309-180 ©2003 The Institute & Guild of Brewing