β-Glucans in malting and brewing

Dissertation

Silja Home

Research output: ThesisDissertationCollection of Articles

Abstract

β-Glucans are the main components of barley cell walls. The cellular structure of barley endosperm must be enzymatically degraded during the germination process before the starch can be released and hydrolyzed in mashing. In the present study a selection procedure emphasizing the structural properties of the barley grain and the degradation of β-glucans during malting was developed. The milling energy of barley or acid extract viscosity were useful analytical methods for the selection of barley lines in preliminary screening. A small scale micromalting with subsequent determination of milling energy of malt predicted the modification rate and was recommended for the selection phase. In the final evaluation the major emphasis must be placed on the homogenity of cell wall degradation. The quality of barley is affected by the weather conditions during the growing season. The addition of fungal cellulase together with gibberellic acid in malting, a method called 'enzymatic abrasion', was used to adjust the quality of malt. This resulted in accelerated malt modification, improved β-glucan degradation and marked improvement in beer filtration. Mash separation or beer filtration problems are occasionally encountered in the brewing process. These may be caused by the uneven quality of malt or by the use of unmalted barley as an adjunct. Mashing-in at 48°C was most optimal for the activity of endogenous β-glucanase in malt. By extending the time at the mashing-in temperature it was possible to promote β-glucan degradation. Attention must also be paid to the mash tun design. Efficient stirring and heating led to increased release of β-glucans. Two other mashing variables, mash thickness and grist coarseness, also affected the β-glucan content in wort. The addition of a fungal cellulase preparation either in mashing or in fermentation provided an efficient means of improving beer filterability. The advantage of using the external enzyme in mashing is that it is inactivated during boiling. The increased cost of the manyfold amount of enzyme needed compared with the addition in fermentation can probably be covered by increased brewhouse yield and improved lautering. A novel solution to beer filtration problems is the use of glucanolytic brewer's yeast. However, general acceptance of the use of genetically modified yeasts still requires some time.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Helsinki University of Technology
Award date2 Jun 1993
Place of PublicationEspoo
Publisher
Print ISBNs951-38-4380-7
Publication statusPublished - 1993
MoE publication typeG5 Doctoral dissertation (article)

Fingerprint

malting
mashing
brewing
glucans
malt
barley
beers
mash
degradation
endo-1,4-beta-glucanase
filterability
fermentation
cell walls
brewers yeast
wort (brewing)
cell structures
energy
enzymes
boiling
gibberellic acid

Keywords

  • ß-glucans
  • barley
  • breeding
  • malting
  • mashing
  • brewing
  • yeasts
  • enzymes
  • cellulase

Cite this

Home, S. (1993). β-Glucans in malting and brewing: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Home, Silja. / β-Glucans in malting and brewing : Dissertation. Espoo : VTT Technical Research Centre of Finland, 1993. 96 p.
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abstract = "β-Glucans are the main components of barley cell walls. The cellular structure of barley endosperm must be enzymatically degraded during the germination process before the starch can be released and hydrolyzed in mashing. In the present study a selection procedure emphasizing the structural properties of the barley grain and the degradation of β-glucans during malting was developed. The milling energy of barley or acid extract viscosity were useful analytical methods for the selection of barley lines in preliminary screening. A small scale micromalting with subsequent determination of milling energy of malt predicted the modification rate and was recommended for the selection phase. In the final evaluation the major emphasis must be placed on the homogenity of cell wall degradation. The quality of barley is affected by the weather conditions during the growing season. The addition of fungal cellulase together with gibberellic acid in malting, a method called 'enzymatic abrasion', was used to adjust the quality of malt. This resulted in accelerated malt modification, improved β-glucan degradation and marked improvement in beer filtration. Mash separation or beer filtration problems are occasionally encountered in the brewing process. These may be caused by the uneven quality of malt or by the use of unmalted barley as an adjunct. Mashing-in at 48°C was most optimal for the activity of endogenous β-glucanase in malt. By extending the time at the mashing-in temperature it was possible to promote β-glucan degradation. Attention must also be paid to the mash tun design. Efficient stirring and heating led to increased release of β-glucans. Two other mashing variables, mash thickness and grist coarseness, also affected the β-glucan content in wort. The addition of a fungal cellulase preparation either in mashing or in fermentation provided an efficient means of improving beer filterability. The advantage of using the external enzyme in mashing is that it is inactivated during boiling. The increased cost of the manyfold amount of enzyme needed compared with the addition in fermentation can probably be covered by increased brewhouse yield and improved lautering. A novel solution to beer filtration problems is the use of glucanolytic brewer's yeast. However, general acceptance of the use of genetically modified yeasts still requires some time.",
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author = "Silja Home",
note = "Project code: BIO8200",
year = "1993",
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isbn = "951-38-4380-7",
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Home, S 1993, 'β-Glucans in malting and brewing: Dissertation', Doctor Degree, Helsinki University of Technology, Espoo.

β-Glucans in malting and brewing : Dissertation. / Home, Silja.

Espoo : VTT Technical Research Centre of Finland, 1993. 96 p.

Research output: ThesisDissertationCollection of Articles

TY - THES

T1 - β-Glucans in malting and brewing

T2 - Dissertation

AU - Home, Silja

N1 - Project code: BIO8200

PY - 1993

Y1 - 1993

N2 - β-Glucans are the main components of barley cell walls. The cellular structure of barley endosperm must be enzymatically degraded during the germination process before the starch can be released and hydrolyzed in mashing. In the present study a selection procedure emphasizing the structural properties of the barley grain and the degradation of β-glucans during malting was developed. The milling energy of barley or acid extract viscosity were useful analytical methods for the selection of barley lines in preliminary screening. A small scale micromalting with subsequent determination of milling energy of malt predicted the modification rate and was recommended for the selection phase. In the final evaluation the major emphasis must be placed on the homogenity of cell wall degradation. The quality of barley is affected by the weather conditions during the growing season. The addition of fungal cellulase together with gibberellic acid in malting, a method called 'enzymatic abrasion', was used to adjust the quality of malt. This resulted in accelerated malt modification, improved β-glucan degradation and marked improvement in beer filtration. Mash separation or beer filtration problems are occasionally encountered in the brewing process. These may be caused by the uneven quality of malt or by the use of unmalted barley as an adjunct. Mashing-in at 48°C was most optimal for the activity of endogenous β-glucanase in malt. By extending the time at the mashing-in temperature it was possible to promote β-glucan degradation. Attention must also be paid to the mash tun design. Efficient stirring and heating led to increased release of β-glucans. Two other mashing variables, mash thickness and grist coarseness, also affected the β-glucan content in wort. The addition of a fungal cellulase preparation either in mashing or in fermentation provided an efficient means of improving beer filterability. The advantage of using the external enzyme in mashing is that it is inactivated during boiling. The increased cost of the manyfold amount of enzyme needed compared with the addition in fermentation can probably be covered by increased brewhouse yield and improved lautering. A novel solution to beer filtration problems is the use of glucanolytic brewer's yeast. However, general acceptance of the use of genetically modified yeasts still requires some time.

AB - β-Glucans are the main components of barley cell walls. The cellular structure of barley endosperm must be enzymatically degraded during the germination process before the starch can be released and hydrolyzed in mashing. In the present study a selection procedure emphasizing the structural properties of the barley grain and the degradation of β-glucans during malting was developed. The milling energy of barley or acid extract viscosity were useful analytical methods for the selection of barley lines in preliminary screening. A small scale micromalting with subsequent determination of milling energy of malt predicted the modification rate and was recommended for the selection phase. In the final evaluation the major emphasis must be placed on the homogenity of cell wall degradation. The quality of barley is affected by the weather conditions during the growing season. The addition of fungal cellulase together with gibberellic acid in malting, a method called 'enzymatic abrasion', was used to adjust the quality of malt. This resulted in accelerated malt modification, improved β-glucan degradation and marked improvement in beer filtration. Mash separation or beer filtration problems are occasionally encountered in the brewing process. These may be caused by the uneven quality of malt or by the use of unmalted barley as an adjunct. Mashing-in at 48°C was most optimal for the activity of endogenous β-glucanase in malt. By extending the time at the mashing-in temperature it was possible to promote β-glucan degradation. Attention must also be paid to the mash tun design. Efficient stirring and heating led to increased release of β-glucans. Two other mashing variables, mash thickness and grist coarseness, also affected the β-glucan content in wort. The addition of a fungal cellulase preparation either in mashing or in fermentation provided an efficient means of improving beer filterability. The advantage of using the external enzyme in mashing is that it is inactivated during boiling. The increased cost of the manyfold amount of enzyme needed compared with the addition in fermentation can probably be covered by increased brewhouse yield and improved lautering. A novel solution to beer filtration problems is the use of glucanolytic brewer's yeast. However, general acceptance of the use of genetically modified yeasts still requires some time.

KW - ß-glucans

KW - barley

KW - breeding

KW - malting

KW - mashing

KW - brewing

KW - yeasts

KW - enzymes

KW - cellulase

M3 - Dissertation

SN - 951-38-4380-7

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Home S. β-Glucans in malting and brewing: Dissertation. Espoo: VTT Technical Research Centre of Finland, 1993. 96 p.