Reference Number: 613
Lactic Acid Bacteria: Prevalence
It has been observed that bread containing lactic acid produced during the sourdough fermentation or added directly, has the ability to lower the postprandial glucose and insulin responses in humans. The main objective of the present work was to evaluate the possible mechanisms for a lowered glucose response to bread containing lactic acid, and to determine whether the same phenomenon also occurs when lactic acid is added to other cereal products. The rate of starch hydrolysis in bread and bread-like products was studied using an in vitro enzymatic approach. In addition, blood glucose and insulin responses to different lactic acid fermented barley gruels were evaluated in healthy subjects. It was concluded that the inclusion of lactic acid in bread reduces the rate of starch digestion by creating interactions between the gluten and starch. The presence of lactic acid during starch gelatinisation appeared to be a prerequisite for a reduced starch bioavailability. No effect of lactic acid was seen in gruels where the acid was formed after heat-treatment.
Significance of this study for the baker:
The current work suggests that the presence of lactic acid during heat treatment promote interactions between starch and gluten, hence reducing starch bioavailability. This is the probable mechanism for the lowered glycaemia seen in bread products with lactic acid. The presence of lactic acid during heat treatment appears to be a prerequisite and no effect was seen when lactic acid was added following simulated baking nor produced post-gelatinisation in a gruel product.