Sourdough: A tool for the improved flavour, texture and shelf-life of wheat bread: Dissertation

Kati Katina

Research output: ThesisDissertationCollection of Articles

Abstract

The aim of this thesis was to develop means to optimize the biochemical activity of sourdough to achieve improved bread flavour, texture and shelf-life, and to determine how the structure of fresh and aged bread is altered by the use of sourdough. The influence of process conditions of prefermentation on subsequent bread quality is clarified through this thesis. The importance of an optimised sourdough process in improving the flavour and texture of subsequent bread was demonstrated. The sourdough process had to be optimised in a strain-specific manner to obtain improved flavour and texture. Lactic acid bacteria fermented sourdoughs were more effective in tuning bread quality compared to yeasted preferments if the appropriate conditions were utilised. The ash content of flour and fermentation time were the main factors regulating bread flavour and texture in all of the sourdough types studied. The possibility to improve bread flavour by utilising sourdough with moderate acidity and an enhanced level of amino acids was demonstrated in this study. Bread volume and shelf-life were also improved by sourdough, which was fermented with low ash content flour and with optimised fermentation time. A new type of sourdough was presented: bran sourdough, which could effectively compensate the negative effect of added wheat bran on bread volume and shelf-life in high-fibre baking. An altered microstructure (improved protein network, enhanced swelling of starch and modified degradation of cell wall components) of bran sourdough breads, especially if made with enzymes, was related to improved volume. A reduced staling rate of bran sourdough breads was further explained due to reduced starch retrogradation and a slower loss of molecular mobility. In conclusion, wheat bread flavour and texture were effectively modified using optimised sourdough. Bran sourdough was introduced as a potential tool for the future development of technologically and nutritionally superior raw materials for all cereal foods, such as bread, breakfast and snack products.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • University of Helsinki
Supervisors/Advisors
  • Poutanen, Kaisa, Supervisor
  • Autio, Karin, Supervisor, External person
Award date26 Aug 2005
Place of PublicationEspoo
Publisher
Print ISBNs951-38-6649-1
Electronic ISBNs951-38-6650-5
Publication statusPublished - 2005
MoE publication typeG5 Doctoral dissertation (article)

Fingerprint

sourdough
shelf life
flavor
breads
texture
wheat
bran
sourdough bread
ash content
flour
fermentation
starch
grain foods
retrogradation
breakfast
snacks
cell wall components
wheat bran
baking
microstructure

Keywords

  • sourdough
  • bread
  • flavour
  • texture
  • processing conditions
  • acidity
  • amino acids
  • volatile compounds
  • bran
  • high-fibre baking

Cite this

Katina, K. (2005). Sourdough: A tool for the improved flavour, texture and shelf-life of wheat bread: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Katina, Kati. / Sourdough : A tool for the improved flavour, texture and shelf-life of wheat bread: Dissertation. Espoo : VTT Technical Research Centre of Finland, 2005. 96 p.
@phdthesis{5b83512694274785ad1d5028794e1f71,
title = "Sourdough: A tool for the improved flavour, texture and shelf-life of wheat bread: Dissertation",
abstract = "The aim of this thesis was to develop means to optimize the biochemical activity of sourdough to achieve improved bread flavour, texture and shelf-life, and to determine how the structure of fresh and aged bread is altered by the use of sourdough. The influence of process conditions of prefermentation on subsequent bread quality is clarified through this thesis. The importance of an optimised sourdough process in improving the flavour and texture of subsequent bread was demonstrated. The sourdough process had to be optimised in a strain-specific manner to obtain improved flavour and texture. Lactic acid bacteria fermented sourdoughs were more effective in tuning bread quality compared to yeasted preferments if the appropriate conditions were utilised. The ash content of flour and fermentation time were the main factors regulating bread flavour and texture in all of the sourdough types studied. The possibility to improve bread flavour by utilising sourdough with moderate acidity and an enhanced level of amino acids was demonstrated in this study. Bread volume and shelf-life were also improved by sourdough, which was fermented with low ash content flour and with optimised fermentation time. A new type of sourdough was presented: bran sourdough, which could effectively compensate the negative effect of added wheat bran on bread volume and shelf-life in high-fibre baking. An altered microstructure (improved protein network, enhanced swelling of starch and modified degradation of cell wall components) of bran sourdough breads, especially if made with enzymes, was related to improved volume. A reduced staling rate of bran sourdough breads was further explained due to reduced starch retrogradation and a slower loss of molecular mobility. In conclusion, wheat bread flavour and texture were effectively modified using optimised sourdough. Bran sourdough was introduced as a potential tool for the future development of technologically and nutritionally superior raw materials for all cereal foods, such as bread, breakfast and snack products.",
keywords = "sourdough, bread, flavour, texture, processing conditions, acidity, amino acids, volatile compounds, bran, high-fibre baking",
author = "Kati Katina",
year = "2005",
language = "English",
isbn = "951-38-6649-1",
series = "VTT Publications",
publisher = "VTT Technical Research Centre of Finland",
number = "569",
address = "Finland",
school = "University of Helsinki",

}

Katina, K 2005, 'Sourdough: A tool for the improved flavour, texture and shelf-life of wheat bread: Dissertation', Doctor Degree, University of Helsinki, Espoo.

Sourdough : A tool for the improved flavour, texture and shelf-life of wheat bread: Dissertation. / Katina, Kati.

Espoo : VTT Technical Research Centre of Finland, 2005. 96 p.

Research output: ThesisDissertationCollection of Articles

TY - THES

T1 - Sourdough

T2 - A tool for the improved flavour, texture and shelf-life of wheat bread: Dissertation

AU - Katina, Kati

PY - 2005

Y1 - 2005

N2 - The aim of this thesis was to develop means to optimize the biochemical activity of sourdough to achieve improved bread flavour, texture and shelf-life, and to determine how the structure of fresh and aged bread is altered by the use of sourdough. The influence of process conditions of prefermentation on subsequent bread quality is clarified through this thesis. The importance of an optimised sourdough process in improving the flavour and texture of subsequent bread was demonstrated. The sourdough process had to be optimised in a strain-specific manner to obtain improved flavour and texture. Lactic acid bacteria fermented sourdoughs were more effective in tuning bread quality compared to yeasted preferments if the appropriate conditions were utilised. The ash content of flour and fermentation time were the main factors regulating bread flavour and texture in all of the sourdough types studied. The possibility to improve bread flavour by utilising sourdough with moderate acidity and an enhanced level of amino acids was demonstrated in this study. Bread volume and shelf-life were also improved by sourdough, which was fermented with low ash content flour and with optimised fermentation time. A new type of sourdough was presented: bran sourdough, which could effectively compensate the negative effect of added wheat bran on bread volume and shelf-life in high-fibre baking. An altered microstructure (improved protein network, enhanced swelling of starch and modified degradation of cell wall components) of bran sourdough breads, especially if made with enzymes, was related to improved volume. A reduced staling rate of bran sourdough breads was further explained due to reduced starch retrogradation and a slower loss of molecular mobility. In conclusion, wheat bread flavour and texture were effectively modified using optimised sourdough. Bran sourdough was introduced as a potential tool for the future development of technologically and nutritionally superior raw materials for all cereal foods, such as bread, breakfast and snack products.

AB - The aim of this thesis was to develop means to optimize the biochemical activity of sourdough to achieve improved bread flavour, texture and shelf-life, and to determine how the structure of fresh and aged bread is altered by the use of sourdough. The influence of process conditions of prefermentation on subsequent bread quality is clarified through this thesis. The importance of an optimised sourdough process in improving the flavour and texture of subsequent bread was demonstrated. The sourdough process had to be optimised in a strain-specific manner to obtain improved flavour and texture. Lactic acid bacteria fermented sourdoughs were more effective in tuning bread quality compared to yeasted preferments if the appropriate conditions were utilised. The ash content of flour and fermentation time were the main factors regulating bread flavour and texture in all of the sourdough types studied. The possibility to improve bread flavour by utilising sourdough with moderate acidity and an enhanced level of amino acids was demonstrated in this study. Bread volume and shelf-life were also improved by sourdough, which was fermented with low ash content flour and with optimised fermentation time. A new type of sourdough was presented: bran sourdough, which could effectively compensate the negative effect of added wheat bran on bread volume and shelf-life in high-fibre baking. An altered microstructure (improved protein network, enhanced swelling of starch and modified degradation of cell wall components) of bran sourdough breads, especially if made with enzymes, was related to improved volume. A reduced staling rate of bran sourdough breads was further explained due to reduced starch retrogradation and a slower loss of molecular mobility. In conclusion, wheat bread flavour and texture were effectively modified using optimised sourdough. Bran sourdough was introduced as a potential tool for the future development of technologically and nutritionally superior raw materials for all cereal foods, such as bread, breakfast and snack products.

KW - sourdough

KW - bread

KW - flavour

KW - texture

KW - processing conditions

KW - acidity

KW - amino acids

KW - volatile compounds

KW - bran

KW - high-fibre baking

M3 - Dissertation

SN - 951-38-6649-1

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Katina K. Sourdough: A tool for the improved flavour, texture and shelf-life of wheat bread: Dissertation. Espoo: VTT Technical Research Centre of Finland, 2005. 96 p.