Effects of Raised Temperatures During Steeping and Germination on Proteolysis During Malting

Abstract

Raising the temperature from 16°C to 20°C or 25°C for prolonged periods during steeping or germination reduces HWE and TSN and slows down wort separation in laboratory mashes. When the higher temperatures are applied only during the last steep or the first two days of germination the initial rate of modification is accelerated, as is the development of a-amylase and endopeptidase. After four or five days germination the levels of enzyme activity are substantially lower than in the control malt. However, some barleys give malts with acceptable standard analyses after 4 rather than 5 days of germination.

Modification of the Methods for the Extraction of Carboxypeptidase and Proteinase Activities from Sorghum Malts

“…It is equally remarkable that the proteinase enzyme activity increases in all the malt varieties were moderate or not as pronounced as in the carboxypeptidase enzyme. Although several-fold increases in proteinase activity were reported during sorghum germination 3,21,26,37 and barley germination 6,7,10,30,31,33 , our results are in consonance with the moderate increase reported earlier by Evans and Taylor 19,20 .…”

An accelerated malting procedure - influences on malt quality and cost savings by reduced energy consumption and malting losses

“…Steeping at temperatures up to 25°C compared with 15°C, germinating at 20-24°C instead of 16°C and withering at 30-37.5°C compared with 60°C were shown to result in a faster cytolytic modification. Also other authors found an enhanced cell wall degradation when steeping (22,26) and germinating at higher temperatures (10,21,32) and at lower withering temperatures (41,42,68). The found optimal parameters combined in the accelerated malting programmes succeeded sufficiently in the shorter process.…”

“…Proteolytic modification is said to be reduced at higher germination temperatures resulting in lower free amino nitrogen (FAN) and soluble nitrogen content and thus decreased Kolbach indices, which can be insufficient for adequate yeast nutrition and foam stability in the final beer (12,16,21,28,29). In addition, Baxter and coworkers (13,26) and Reeves et al (25) observed an impaired filterability of mashes produced from warm steeped and germinated malt. On the other hand, a generally improved cytolytic modification could be observed when applying increased steeping and germination temperatures, as shown by several authors (10,12,21,22,(26)(27)(28)(29)31,34).…”

“…In addition, Baxter and coworkers (13,26) and Reeves et al (25) observed an impaired filterability of mashes produced from warm steeped and germinated malt. On the other hand, a generally improved cytolytic modification could be observed when applying increased steeping and germination temperatures, as shown by several authors (10,12,21,22,(26)(27)(28)(29)31,34). Sommer (10) evaluated the results of Schilfarth et al (32) and Weith (21) regarding the influence of increased germination temperature for accelerating cytolytic modification with regard to economic efficiency.…”

A temperatura no desenvolvimento da atividade das enzimas (1-3, 1-4)- β-glucanases e degradação de β-glucanos durante a malteação

“…Após o efeito indutor inicial, observar-se-ia uma queda na atividade das ß-glucanases, amilases e proteases, antes da finalização do processo, resultando em baixa produção de extrato e nitrogênio solúvel, enquanto a viscosidade permaneceria alta (BAXTER & O FARRELL, 1980;BRIGGS, 1998). Como explicado anteriormente, até completar três dias de germinação, foi adicionada água aos grãos de cevada em quantidade suficiente para que atingissem umidade em torno de 46% e o efeito da temperatura utilizada durante a germinação também foi observado durante esse procedimento.…”