The formation and hydrolysis of barley malt gel-protein under different mashing conditions

Saara Pöyri (Corresponding Author), M. Mikola, T. Sontag-Strohm, Anu Kaukovirta-Norja, Silja Home

Research output: Contribution to journalArticleScientificpeer-review

14 Citations (Scopus)

Abstract

The effect of oxidation and proteolysis on the amount of gel-protein aggregate was investigated both in vivo during mashing and in vitro. The oxidation of the free thiol groups of proteins to disulphide bridges during mashing appeared to be a good indicator of the formation of gel-protein aggregate. The pH optimum of the oxidation varied according to the isothermal mashing temperature. The results suggested that the oxidation of the thiol groups maybe a result of some kind of enzymatic activity. In vitro experiments showed that the proteolysis of the gel-protein aggregate was strongest at pH 5.0 and temperature denaturation occurred only at temperatures over 80°C. Mashing experiments on the other hand suggested that the proteolysis of the monomer subunits of gel-protein (i.e. B- and D-hordein) had a stronger effect on the final amount of the gel-protein aggregate than the hydrolysis of the aggregate.
Original languageEnglish
Pages (from-to)261-267
JournalJournal of the Institute of Brewing
Volume108
Issue number2
DOIs
Publication statusPublished - 2002
MoE publication typeA1 Journal article-refereed

Fingerprint

malt
protein aggregates
Hordeum
Hydrolysis
hydrolysis
Gels
barley
gels
proteolysis
oxidation
Proteolysis
Proteins
thiols
Sulfhydryl Compounds
proteins
Temperature
hordein
temperature
Glutens
denaturation

Keywords

  • Gel-protein
  • hordein
  • hydrolysis
  • mashing
  • oxidation
  • proteolysis

Cite this

Pöyri, Saara ; Mikola, M. ; Sontag-Strohm, T. ; Kaukovirta-Norja, Anu ; Home, Silja. / The formation and hydrolysis of barley malt gel-protein under different mashing conditions. In: Journal of the Institute of Brewing. 2002 ; Vol. 108, No. 2. pp. 261-267.
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abstract = "The effect of oxidation and proteolysis on the amount of gel-protein aggregate was investigated both in vivo during mashing and in vitro. The oxidation of the free thiol groups of proteins to disulphide bridges during mashing appeared to be a good indicator of the formation of gel-protein aggregate. The pH optimum of the oxidation varied according to the isothermal mashing temperature. The results suggested that the oxidation of the thiol groups maybe a result of some kind of enzymatic activity. In vitro experiments showed that the proteolysis of the gel-protein aggregate was strongest at pH 5.0 and temperature denaturation occurred only at temperatures over 80°C. Mashing experiments on the other hand suggested that the proteolysis of the monomer subunits of gel-protein (i.e. B- and D-hordein) had a stronger effect on the final amount of the gel-protein aggregate than the hydrolysis of the aggregate.",
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The formation and hydrolysis of barley malt gel-protein under different mashing conditions. / Pöyri, Saara (Corresponding Author); Mikola, M.; Sontag-Strohm, T.; Kaukovirta-Norja, Anu; Home, Silja.

In: Journal of the Institute of Brewing, Vol. 108, No. 2, 2002, p. 261-267.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - The formation and hydrolysis of barley malt gel-protein under different mashing conditions

AU - Pöyri, Saara

AU - Mikola, M.

AU - Sontag-Strohm, T.

AU - Kaukovirta-Norja, Anu

AU - Home, Silja

PY - 2002

Y1 - 2002

N2 - The effect of oxidation and proteolysis on the amount of gel-protein aggregate was investigated both in vivo during mashing and in vitro. The oxidation of the free thiol groups of proteins to disulphide bridges during mashing appeared to be a good indicator of the formation of gel-protein aggregate. The pH optimum of the oxidation varied according to the isothermal mashing temperature. The results suggested that the oxidation of the thiol groups maybe a result of some kind of enzymatic activity. In vitro experiments showed that the proteolysis of the gel-protein aggregate was strongest at pH 5.0 and temperature denaturation occurred only at temperatures over 80°C. Mashing experiments on the other hand suggested that the proteolysis of the monomer subunits of gel-protein (i.e. B- and D-hordein) had a stronger effect on the final amount of the gel-protein aggregate than the hydrolysis of the aggregate.

AB - The effect of oxidation and proteolysis on the amount of gel-protein aggregate was investigated both in vivo during mashing and in vitro. The oxidation of the free thiol groups of proteins to disulphide bridges during mashing appeared to be a good indicator of the formation of gel-protein aggregate. The pH optimum of the oxidation varied according to the isothermal mashing temperature. The results suggested that the oxidation of the thiol groups maybe a result of some kind of enzymatic activity. In vitro experiments showed that the proteolysis of the gel-protein aggregate was strongest at pH 5.0 and temperature denaturation occurred only at temperatures over 80°C. Mashing experiments on the other hand suggested that the proteolysis of the monomer subunits of gel-protein (i.e. B- and D-hordein) had a stronger effect on the final amount of the gel-protein aggregate than the hydrolysis of the aggregate.

KW - Gel-protein

KW - hordein

KW - hydrolysis

KW - mashing

KW - oxidation

KW - proteolysis

U2 - 10.1002/j.2050-0416.2002.tb00550.x

DO - 10.1002/j.2050-0416.2002.tb00550.x

M3 - Article

VL - 108

SP - 261

EP - 267

JO - Journal of the Institute of Brewing

JF - Journal of the Institute of Brewing

SN - 0046-9750

IS - 2

ER -