Reference Number: 580
Year: 2009
Link: Link to original paper
Health: Diabetes
Nutrition: Fibre | Resistant starch
Summary
To evaluate the influence of sourdough fermentation on starch digestibility in bread, four experimental breads were obtained, prepared from two different wheat flours (whole or white) by two different leavening techniques (sourdough and with Saccharomyces cerevisiae). Products were analyzed for their starch, fiber and resistant starch (RS) content and then submitted to in vitro hydrolysis with porcine alpha-amylase. On the same breads, postprandial blood glucose was evaluated in healthy human subjects. Both sourdough fermented breads gave glycaemic responses significantly lower (p < 0.001) than the corresponding products leavened with S. cerevisiae. On the contrary, the presence of fiber did not influence the glycaemic potential of breads. RS levels were higher in the sourdough products, whereas no differences were observed either in the rate of starch hydrolysis or in the degree of polymerization of the starch residues after the in vitro hydrolysis. We may conclude that sourdough fermentation is a technique able to reduce the glycaemic response to bread and that the mechanism does not seem related to the rate of starch hydrolysis.
The significance of this study to the baker:
To evaluate the influence of sourdough fermentation on starch digestibility in bread, four experimental breads were obtained, prepared from two different wheat flours (whole or white) by two different leavening techniques (sourdough and with Saccharomyces cerevisiae):
Both sourdough fermented breads gave glycaemic responses significantly lower than the corresponding products leavened with S. cerevisiae. Considering that high glycemic variability is associated with negative moods and lower quality of life, this study suggests that sourdough could regulate mood better than refined, wheat breads… Additionally, sourdough was shown to have higher resistant starch content, a prebiotic which beneficial bacteria feed on.