The Sourdough School

BREAD COURSES || NUTRITION TRAINING || DIGESTION ANALYSIS || PERSONALISED BREAD

Learn to bake, eat, and share the healthiest bread in the world. Discover how to bake as Lifestyle Medicine from the walled gardens of Dr Vanessa Kimbell’s beautiful Victorian home in rural Northamptonshire in the UK, where we train healthcare professionals, teach bakers, and support individuals to bake personalised bread using nutrigenetics and gut health assessments.

+44(0)7813308301
[email protected]
Follow on Instagram
  • Facebook
  • Instagram
  • Pinterest
  • Twitter

Student Login

Book a consultation

Navigation
  • courses
    • Book a Call
    • 12 week Bread Delivery Gut Reset Course
    • 1 Day Practitioner BALM Training Day
    • 3 Day Bake for Heath Workshops
    • 6 Day Reset Retreat
    • Annual Tuscan Retreat
    • The Diploma
  • Personalisation
    • Bread & Health Assessments
    • Personalising Bread
    • Personalising Bread Using Nutrigenetics
    • Priority Access: Join the Waiting List
  • About
    • About The Sourdough School
    • Contact Us & FAQ
    • General FAQ’s about The School
    • Request a Callback
    • Where to stay & more
    • Reviews
    • The Team
    • A Social Enterprise
    • Contributors & Guest Tutors
    • What Our Students Say
    • Login
  • Our Approach
    • Baking as Lifestyle Medicine (BALM)
    • Prove it – The Case Studies
    • 12 Week Student Support Pack
    • Bread as Preventative Health
    • Training Bakers & Healthcare Professionals
    • Diversity Bread™
    • BALM & Bread in The Blue Zone
    • Proven: Bread Podcast
  • Admissions
    • Request a callback
  • Shop
    • Our Flour and Ingredients
    • Our Books
    • Equipment
    • Flours From Farmers Directory
    • Add Farmer to the Directory

87 - ‘Production of microbial exopolysaccharides in the sourdough and its effects on the rheological properties of dough’. Food Research International. 41, 948–951

Reference Number: 87

Year: 2008

Authors: Ali Ketabi, Sabihe Soleimanian-Zad, Mahdi Kadivar, Mahmoud Sheikh-Zeinoddin

Link: Link to original paper

Summary

Introduction

Exopolysaccharides (EPS) are exogenous microbial metabolites which are secreted mainly by bacteria and microalgae during growth. In addition to natural polysaccharides present in cereal grains flour and dough, microbial flora is usually involved in production of polysaccharide on sourdough fermentation.

Methods

Total polysaccharides (microbial and flour) were extracted from sourdough and dough samples dehydrated and were added at the rate of 0%, 0.25%, 0.5%, 1%, 1.5%, 2% and 2.5% (w/w flour based) on the dough to investigate its effects on the rheological properties of the dough.

Results

Addition of polysaccharides to the dough increased the water absorption and decreased the dough softening after 20 min. Resistance to extension after 45, 90 and 135 min resting time was decreased by increasing the percentage of the added polysaccharides. Longer fermentation time for each level of polysaccharides led to greater stability. No significant differences were observed in the extensibility of dough. The overall effects of different levels of added polysaccharides resulted in a decrease in resistance to extension ratio of the samples. Energy input decreased in all cases. It seems therefore that addition of polysaccharides may be useful when bread is to be made with stronger flour and longer fermentation time is needed.

 

SIGNIFICANCE OF THIS STUDY

Bacteria in sourdough starters produce complex polysaccharides called exopolysaccharides that play an important role in contributing to the optimum structure of sourdough breads. They are called ‘exo’ polysaccharides because they are released by bacteria into the surrounding during the fermentation process. The study found that longer fermentation times resulted in increased levels of exopolysaccharides which resulted in more texturally stable breads. Both microbial expolysaccharides and plant polysaccharides contribute to the structural layout that is important in creating sourdough bread that is texturally superior to modern fast fermented breads.

 

Take a look at our courses at The Sourdough School

All reasonable care is taken when advising about health aspects of bread, but the information that we share is not intended to take the place of treatment by a qualified medical practitioner. You must seek professional advice if you are in any doubt about any medical condition. Any application of the ideas and information contained on this website is at the reader's sole discretion and risk.

  • Facebook
  • Instagram
  • Pinterest
  • Twitter

Email Sign Up

BANT Member
Lifecode GX

Terms and Conditions | Privacy Policy
Copyright © 2025 Vanessa Kimbell
Call +44 (0)7813308301 | Email [email protected]
Registered in England & Wales: 08412236
Website by Callia Web