Lakkaasin ja ksylanaasin vaikutus vehnäjauho- ja gluteenitaikinan rakenteen muodostumiseen

Diplomityö

Emilia Selinheimo

Research output: ThesisMaster's thesisTheses

Abstract

In the literature survey, properties of wheat flour and dough as well as the structure formation of wheat bread were discussed, with special emphasis on rheology. Also the theory and a few measurement methods of the rheology were shortly introduced. Considering the influence of enzymes on breadmaking, a structure formation by an oxidative mechanism was discussed. The enzymes that were viewed more precisely on their effect on the structure formation of wheat bread included lipoxygenase, glucose oxidase, peroxidase, laccase and transglutaminase. In the experimental part of the study, the effect of Aspergillus oryzae and Bacillus subtilis xylanases and Trametes hirsuta and Melanocarpus albomyces laccases, separately and together, on the structure of wheat flour dough and gluten dough were examined. The experiments of added free ferulic acid (FA) were done to clarify the role of FA in dough structure formation. The rheological experiments were performed with Kieffer dough and gluten extensibility rig, when the dough extensibility Ex and the resistance to stretching Rmax, were determined. In a rheology point of view, laccases increased the maximum resistance Rmax of dough and decreased the dough extensibility Ex at Rmax, whereas xylanases decreased the Rmax of dough and increased the Ex at Rmax in flour and gluten doughs. Considering the protein-AX fraction, hardening by laccases and softening by xylanases were weaker in gluten doughs, which was presumably due to the lower AX content in gluten. Like xylanases, the added free FA softened the flour dough structure, as well. As a function of dough resting time, the structure of laccase treated doughs was observed to soften. The softening effect was strengthened as a function of laccase activity. The reason for the softening phenomenon was probably the laccase-mediated depolymerization of crosslinked arabinoxylan network, resulting from mobile FA radicals. Combined laccase and xylanase experiments led to doughs of higher Rmax, with no remarkable change in Ex. The effect of laccase seemed to be predominant, especially at low xylanase dosages, but when xylanase was added to flour dough at high concentration, the hardening effect of laccase on dough was decreased. Presumably, when the AX fraction was hydrolyzed effectively by xylanase, laccase was not able to create a strong AX network. Similar decrease in laccase-mediated hardening in doughs was not seen, when performing the combined laccase and xylanase test with gluten, which was presumably due to low AX content of gluten. The results indicated the critical role of feruloylated arabinoxylan fraction in laccase-catalyzed structure formation both in flour and gluten, although in gluten doughs, protein fraction might have also been affected.
Original languageEnglish
QualificationMaster Degree
Awarding Institution
  • Helsinki University of Technology
Place of PublicationEspoo
Publisher
Publication statusPublished - 2004
MoE publication typeG2 Master's thesis, polytechnic Master's thesis

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dough
laccase
xylanases
gluten
ferulic acid
extensibility
flour
rheology
arabinoxylan
wheat flour
Coriolus hirsutus
breadmaking
glucose oxidase
wheat
Aspergillus oryzae
depolymerization
protein-glutamine gamma-glutamyltransferase
lipoxygenase
enzymes
Bacillus subtilis

Cite this

Selinheimo, Emilia. / Lakkaasin ja ksylanaasin vaikutus vehnäjauho- ja gluteenitaikinan rakenteen muodostumiseen : Diplomityö. Espoo : Helsinki University of Technology, 2004. 100 p.
@phdthesis{c4cff82eeaea4a778240b4a7f93e7e51,
title = "Lakkaasin ja ksylanaasin vaikutus vehn{\"a}jauho- ja gluteenitaikinan rakenteen muodostumiseen: Diplomity{\"o}",
abstract = "In the literature survey, properties of wheat flour and dough as well as the structure formation of wheat bread were discussed, with special emphasis on rheology. Also the theory and a few measurement methods of the rheology were shortly introduced. Considering the influence of enzymes on breadmaking, a structure formation by an oxidative mechanism was discussed. The enzymes that were viewed more precisely on their effect on the structure formation of wheat bread included lipoxygenase, glucose oxidase, peroxidase, laccase and transglutaminase. In the experimental part of the study, the effect of Aspergillus oryzae and Bacillus subtilis xylanases and Trametes hirsuta and Melanocarpus albomyces laccases, separately and together, on the structure of wheat flour dough and gluten dough were examined. The experiments of added free ferulic acid (FA) were done to clarify the role of FA in dough structure formation. The rheological experiments were performed with Kieffer dough and gluten extensibility rig, when the dough extensibility Ex and the resistance to stretching Rmax, were determined. In a rheology point of view, laccases increased the maximum resistance Rmax of dough and decreased the dough extensibility Ex at Rmax, whereas xylanases decreased the Rmax of dough and increased the Ex at Rmax in flour and gluten doughs. Considering the protein-AX fraction, hardening by laccases and softening by xylanases were weaker in gluten doughs, which was presumably due to the lower AX content in gluten. Like xylanases, the added free FA softened the flour dough structure, as well. As a function of dough resting time, the structure of laccase treated doughs was observed to soften. The softening effect was strengthened as a function of laccase activity. The reason for the softening phenomenon was probably the laccase-mediated depolymerization of crosslinked arabinoxylan network, resulting from mobile FA radicals. Combined laccase and xylanase experiments led to doughs of higher Rmax, with no remarkable change in Ex. The effect of laccase seemed to be predominant, especially at low xylanase dosages, but when xylanase was added to flour dough at high concentration, the hardening effect of laccase on dough was decreased. Presumably, when the AX fraction was hydrolyzed effectively by xylanase, laccase was not able to create a strong AX network. Similar decrease in laccase-mediated hardening in doughs was not seen, when performing the combined laccase and xylanase test with gluten, which was presumably due to low AX content of gluten. The results indicated the critical role of feruloylated arabinoxylan fraction in laccase-catalyzed structure formation both in flour and gluten, although in gluten doughs, protein fraction might have also been affected.",
author = "Emilia Selinheimo",
note = "CA: BEL diplomity{\"o} Helsinki University of Technology. Department of Chemical Technology",
year = "2004",
language = "English",
publisher = "Helsinki University of Technology",
address = "Finland",
school = "Helsinki University of Technology",

}

Selinheimo, E 2004, 'Lakkaasin ja ksylanaasin vaikutus vehnäjauho- ja gluteenitaikinan rakenteen muodostumiseen: Diplomityö', Master Degree, Helsinki University of Technology, Espoo.

Lakkaasin ja ksylanaasin vaikutus vehnäjauho- ja gluteenitaikinan rakenteen muodostumiseen : Diplomityö. / Selinheimo, Emilia.

Espoo : Helsinki University of Technology, 2004. 100 p.

Research output: ThesisMaster's thesisTheses

TY - THES

T1 - Lakkaasin ja ksylanaasin vaikutus vehnäjauho- ja gluteenitaikinan rakenteen muodostumiseen

T2 - Diplomityö

AU - Selinheimo, Emilia

N1 - CA: BEL diplomityö Helsinki University of Technology. Department of Chemical Technology

PY - 2004

Y1 - 2004

N2 - In the literature survey, properties of wheat flour and dough as well as the structure formation of wheat bread were discussed, with special emphasis on rheology. Also the theory and a few measurement methods of the rheology were shortly introduced. Considering the influence of enzymes on breadmaking, a structure formation by an oxidative mechanism was discussed. The enzymes that were viewed more precisely on their effect on the structure formation of wheat bread included lipoxygenase, glucose oxidase, peroxidase, laccase and transglutaminase. In the experimental part of the study, the effect of Aspergillus oryzae and Bacillus subtilis xylanases and Trametes hirsuta and Melanocarpus albomyces laccases, separately and together, on the structure of wheat flour dough and gluten dough were examined. The experiments of added free ferulic acid (FA) were done to clarify the role of FA in dough structure formation. The rheological experiments were performed with Kieffer dough and gluten extensibility rig, when the dough extensibility Ex and the resistance to stretching Rmax, were determined. In a rheology point of view, laccases increased the maximum resistance Rmax of dough and decreased the dough extensibility Ex at Rmax, whereas xylanases decreased the Rmax of dough and increased the Ex at Rmax in flour and gluten doughs. Considering the protein-AX fraction, hardening by laccases and softening by xylanases were weaker in gluten doughs, which was presumably due to the lower AX content in gluten. Like xylanases, the added free FA softened the flour dough structure, as well. As a function of dough resting time, the structure of laccase treated doughs was observed to soften. The softening effect was strengthened as a function of laccase activity. The reason for the softening phenomenon was probably the laccase-mediated depolymerization of crosslinked arabinoxylan network, resulting from mobile FA radicals. Combined laccase and xylanase experiments led to doughs of higher Rmax, with no remarkable change in Ex. The effect of laccase seemed to be predominant, especially at low xylanase dosages, but when xylanase was added to flour dough at high concentration, the hardening effect of laccase on dough was decreased. Presumably, when the AX fraction was hydrolyzed effectively by xylanase, laccase was not able to create a strong AX network. Similar decrease in laccase-mediated hardening in doughs was not seen, when performing the combined laccase and xylanase test with gluten, which was presumably due to low AX content of gluten. The results indicated the critical role of feruloylated arabinoxylan fraction in laccase-catalyzed structure formation both in flour and gluten, although in gluten doughs, protein fraction might have also been affected.

AB - In the literature survey, properties of wheat flour and dough as well as the structure formation of wheat bread were discussed, with special emphasis on rheology. Also the theory and a few measurement methods of the rheology were shortly introduced. Considering the influence of enzymes on breadmaking, a structure formation by an oxidative mechanism was discussed. The enzymes that were viewed more precisely on their effect on the structure formation of wheat bread included lipoxygenase, glucose oxidase, peroxidase, laccase and transglutaminase. In the experimental part of the study, the effect of Aspergillus oryzae and Bacillus subtilis xylanases and Trametes hirsuta and Melanocarpus albomyces laccases, separately and together, on the structure of wheat flour dough and gluten dough were examined. The experiments of added free ferulic acid (FA) were done to clarify the role of FA in dough structure formation. The rheological experiments were performed with Kieffer dough and gluten extensibility rig, when the dough extensibility Ex and the resistance to stretching Rmax, were determined. In a rheology point of view, laccases increased the maximum resistance Rmax of dough and decreased the dough extensibility Ex at Rmax, whereas xylanases decreased the Rmax of dough and increased the Ex at Rmax in flour and gluten doughs. Considering the protein-AX fraction, hardening by laccases and softening by xylanases were weaker in gluten doughs, which was presumably due to the lower AX content in gluten. Like xylanases, the added free FA softened the flour dough structure, as well. As a function of dough resting time, the structure of laccase treated doughs was observed to soften. The softening effect was strengthened as a function of laccase activity. The reason for the softening phenomenon was probably the laccase-mediated depolymerization of crosslinked arabinoxylan network, resulting from mobile FA radicals. Combined laccase and xylanase experiments led to doughs of higher Rmax, with no remarkable change in Ex. The effect of laccase seemed to be predominant, especially at low xylanase dosages, but when xylanase was added to flour dough at high concentration, the hardening effect of laccase on dough was decreased. Presumably, when the AX fraction was hydrolyzed effectively by xylanase, laccase was not able to create a strong AX network. Similar decrease in laccase-mediated hardening in doughs was not seen, when performing the combined laccase and xylanase test with gluten, which was presumably due to low AX content of gluten. The results indicated the critical role of feruloylated arabinoxylan fraction in laccase-catalyzed structure formation both in flour and gluten, although in gluten doughs, protein fraction might have also been affected.

M3 - Master's thesis

PB - Helsinki University of Technology

CY - Espoo

ER -

Selinheimo E. Lakkaasin ja ksylanaasin vaikutus vehnäjauho- ja gluteenitaikinan rakenteen muodostumiseen: Diplomityö. Espoo: Helsinki University of Technology, 2004. 100 p.