Background and Objectives: Bread is one of the most popular foods consumed worldwide. Compared to breads made with refined flour, whole flour breads contain higher concentration of nutrients. Despite nutritional benefits of whole flour, concentration of phytic acid (an anti-nutritional factor) is higher than white flour. Moreover, whole flour produced more acrylamide, which is known to be a toxic and potentially carcinogenic. One option to improve the quality of breads is the use of sourdough biotechnology. Sourdough is a complex biological system, dependent on the microflora. This study aimed at analyzing four strains of lactic acid bacteria (LAB) in sourdough fermentation to reduce phytic acid and acrylamide in whole wheat bread and investigating the correlation of phytic acid concentration with acrylamide production content.
Materials & Methods: The four strains of LAB investigated including Lactobacillus plantarum, L. delbrueckii subsp. bulgaricus, L. sakei, and L. rhamnosus were used to produce sourdough, separately. The sourdoughs in combination with Saccharomyces cerevisiae were used in bread production and examined for their ability to degrade phytic acid and acrylamide.
Results: Dough fermentation decreased about 24% of phytic acid in whole-wheat dough samples and corresponding breads. High total titratable acidity and lactic acid production favored the degradation of phytic acid in breads (r= -0.738, r= -0.578, respectively). Lacto-fermentation also led to 80% reduction in acrylamide, compared to yeast fermentation alone. Higher concentration of phytic acid correlated with higher content of acrylamide (r=0.678).
Conclusion: Sourdough fermentation recipe for preparation of Iranian breads is a forgotten traditional method that if applied, can replace yeast fermentation or various chemical-leavening processes by useful and suitable microbial strains. This method can improve the quality and nutritional value of whole wheat breads.