Influence of the Microbial Starter and the Breadmaking Step on the Free Amino Acid Profiles of Wheat Sours, Doughs, and Breads by Reversed-Phase High-Performance Liquid Chromatography

Reversed-Phase High Performance Liquid Chromatography profiles of twenty-two free amino acids from sour doughs (240 dough yield, 35 °C, 20 h, 1.1% ash content), bread doughs (17.5% sour dough addition, 0.5–0.6% ash content) and breads respectively inoculated with Lactobacillus brevis, 25a (with and without yeast) and Lactobacillus plantarum, L-73 and B-39 (without yeast) are investigated. Interactive influence of both the microbial composition of the starter and the breadmaking steps are observed on the individual amino acid pattern. After proofing, a significant decline is noticed in dicarboxylic acids and amides, Ser, and hydrophobic amino acids as well as in total amino acid content in all samples. The extent in the amino acid assimilation by lactobacilli and mainly by yeast is closely concerned with the strain of lactobacilli. In general, homofermentative lactobacilli induce bigger decreases. In addition, aromatic amino acids noticeably deplete during fermentation of both unsoured doughs and doughs started with L. plantarum strains. Predominant amino acids such as Ala and GABA are sharply promoted as a consequence of enzymatic reactions. Baking generally induces a significant increase in main amino acids except in unsoured doughs and doughs started with L-73. The presence of yeast in the microbial composition of the heterofermentative bacterial starters (25a) leads to greater increases in amino acid levels during baking.