Improvement of fonio dough properties through starch modification by sourdough fermentation

Abstract

Fonio is a West African millet with potential for gluten-free products. Sourdough fermentation improves fonio bread quality. To determine the cause, the effects of sourdough fermentation on the dough quality and starch characteristics of two white and two black fonio types and a white sorghum type were investigated. Sourdough fermentation substantially improved the dough consistency making it more similar to bread wheat flour, as measured by the Mixolab. Sourdough fermentation also increased pasting viscosity, an indication of effects on starch. SEM indicated that sourdough fermentation caused some slight swelling and starch leaching from the fonio starch granules. This was confirmed by an increase in damaged starch. It also caused a substantial reduction in starch gel firmness. Principal component analysis clearly separated fermented and unfermented fonio flours. Damaged starch was associated with fermented fonio, as were Mixolab parameters related to dough stability. Sourdough fermentation thus improves fonio dough and bread quality by bringing about slight changes in the starch granules, which probably increase water absorption and hence improve dough strength and gas holding.

Improvement of maize bread quality through modification of dough rheological properties by lactic acid bacteria fermentation

“…This suggests that lactic acid produced by lactic acid bacteria during sourdough fermentation of maize dough had an effect on the glycosidic bonds in the starch granule, hydrolysing them and enabling the starch granules to absorb water faster. However, since the chemical acidification did not produce the same effect, part of the effect of the lactic acid fermentation was probably due to the activities of endogenous enzymes in the sourdough microorganisms favoured by the low pH, as reported by Edema et al (2013). These authors explained starch modification as slight changes in the starch granules, which probably increased water absorption.…”

“…This was performed as described by Edema et al (2013) with some modifications. The remaining baking ingredients per 100 g of flour were: sugar (10 g), salt (1.5 g), soft margarine (5 g) and instant dried yeast (2 g) and water ( 15 ml).…”

“…According to Edema et al (2013), sourdough fermentation improves fonio dough by increasing the water absorption capacity of the dough. This in-turn improved dough strength and gas holding capacity of the dough.…”

“…Sourdough is a mixture of flour and water that is fermented by naturally occurring lactic acid bacteria (LAB) and yeast (Hammes and Gänzle, 1998). Success has been reported in the use of sourdough fermentation on the improvement of the quality of wheat bread and some wheat-free breads (reviewed by Arendt et al, 2007;Edema et al, 2013).…”

“…The lactic acid bacteria fermentation process also acts on the other major structural component in dough, namely starch (Petrofsky and Hoseney, 1995). Edema et al (2013) attributed the improvement in fonio dough and bread brought about by the use of a sourdough to starch modification (slight granule swelling and probably some leaching of starch molecules) to the activities of endogenous amylases from the sourdough microorganism whose activities were favoured at low pH. This present work will focus on how a sourdough fermentation process,which has proven to be effective in improving the quality of fonio bread (Edema et al, 2013), improves the quality of maize bread with particular attention to its effect on the rheological properties of maize dough.…”