The effect of different compositions of starter cultures developed from phytic acid-degrading lactic acid bacteria on the sensory quality of bread

Abstract

Sourdough is an initial product used in cereal fermentation, usually prepared by adding lactic acid bacteria (LAB) strains to a mixture of wheat and water. Phytic acid present in wheat flours negatively affects the bioavailability of bread. LAB is found to have phytase activity. The present work thus aimed to determine the effect of starter culture combinations developed from phytic acid-degrading LAB (PAD-LAB) strains isolated from sourdough samples on bread sensory quality. De Man, Rogosa, and Sharpe (MRS) agar, MRS Broth, M17 agar, M17 broth, sodium phytate, and mass spectrometry were used to isolate and identify PAD-LAB from sourdough samples. The extracellular phytase activity of PAD-LAB strains was determined by spectrophotometry. Sourdough samples were prepared using different strains having high phytase activity, and breads produced from these samples were evaluated using sensory attributes. Extracellular phytase activities of 30 strains were determined by the spectrophotometric method, showing the highest value at 1109.7 U/mL, and lowest at 386.9 U/mL, with a mean of 685.1 U/mL. Sourdough samples were prepared using five different strains with high phytase activity as starting cultures; and of the four sourdough samples selected, the count of LAB increased (7.80 - 9.87 log CFU/g), pH decreased (3.53 - 4.57), and TTA (total titratable acidity) values increased (10.17 - 14.29 mL) during the fermentation period. In the sensory evaluation, bread produced with starter culture combination CS30 was preferred. In conclusion, it was determined that the bread produced with PAD-LAB strains has an advantage in terms of sensory quality as compared to the control samples.