Abstract
Sourdough fermentation of twenty wheat cultivars was carried out using mixed probiotic culture (Lactobacillus acidophilus UNI, Lactobacillus brevis LR/5 and Lactobacillus plantarum ATCC 8014). The gliadin antigenicity was expressed in terms of its content in twenty different wheat cultivars. The gliadin proteins were characterized by SDS-PAGE and structural changes analyzed on FTIR spectrophotometer. Moreover, changes in the viscoelastic character of fermented and non-fermented dough were studied by rheometry. The results showed a remarkable reduction in antigenicity by 60% (average) in all wheat cultivars on sourdough fermentation. This reduction may be due to the synergistic effect of protease secretion by mixed lactobacilli, responsible for gliadin degradation. These changes in gliadins by mixed culture proteolysis were confirmed on SDS-PAGE on observing new gliadin-derived low molecular weight peptides. The results were further validated by FTIR spectroscopy where structural changes of gliadins were analyzed in the fermented dough. The rheological data indicated a higher storage modulus (G') compared to loss modulus (G″) in both control and fermented flour of all wheat cultivars, however, with a lower efficacy in sourdoughs. The present study thus establishes that mixed culture sourdough fermentation decreases the antigenic potential of gliadins without any change in the rheology and thereby maintaining the baking or viscoelastic properties of the wheat flour.