Mobilisation of Endospermal Reserves During the Germination of Barley

Abstract

The metabolism of the germinating barley seed is a complicated physiological process. From the point of view of industrial malting, the syntheses of amylolytic and proteolytic enzymes as well as the degra dation of endospermal structures are extremely important. In order to control his process the maltster needs to have a good understanding of these processes as well as of the regulatory mechanisms which control them. When a good malting barley is allowed to germinate under traditional conditions for the time needed, a good malt can be produced without this scientific background. The present day brewing industry, however, has to work with barleys which are not of the traditional malting type and further more accelerated processes are an economic necessity. Under these circumstances, the maltster needs all scientific help he can get. Biochemical and physiological research on germination provides him with the tools he needs for process control and optimisation.

The Effect of Barley Adjuncts on Free Amino Nitrogen Contents in Wort

“…It has been widely reported that cysteine and metallo proteinases, the same proteinases indicated for barley adjunct wort from our research, had a high correlation to wort FAN levels in all-malt wort 7,8,10,12,13,23 . These similar consequences from two different production processes seem to conflict at first sight.…”

“…Thirteen different commercial malts from North America and Europe and two malt samples produced in our laboratory were used for wort FAN and proteinase activity analysis (Table I, No. [1][2][3][4][5][6][7][8][9][10][11][12][13][14]20). Four different malting grade barleys were used for wort FAN analysis (Table I, No.…”

Effect of steeping conditions on the amylolytic development of some Nigerian improved sorghum cultivars

“…This means that among other factors that infl uence amylase production by sorghum during malting is the grain genetic property which was evident in the mean α-amylase activity values obtained for all the sorghum cultivars (Table 2). β-Amylase activity: β-Amylase, the sarccharifying malt-enzyme is an exo-enzyme and attack the amylose chain from the non-reducing end liberating β-maltose which has the free hydroxyl group in β-confi guration (Enari and Sopanen 1986). The low level of β-amylase in sorghum is an important physiological difference between sorghum malt and barley malt.…”

Barley and Malt Proteins and Proteinases: II. The Purification and Characterisation of Five Malt Endoproteases, Using the Highly Degradable Barley Protein Fraction (HDBPF) Substrate

“…The importance of these enzymes follows from the fact that the grain has no storage capacity for free amino acids 7,17,20 . During initial embryo development, the grain must provide all the amino acids for the synthesis of hydrolytic enzymes and other essential nitrogenous compounds for sustaining and the continuation of germination 7 . Furthermore, the proteinases facilitate the breakdown of the cell walls and the freeing of starch granules and the release and activation of ␤-amylase 8,21 .…”

“…Endoproteinases are considered to be the key limiting proteolytic activity enzymes amongst the proteinases 7,23 .…”