Effect of Kefiran and Xanthan on Propertiesof Dough and Quality of French Bread

Kefiran، extracted from kefir grains، is a water-soluble، glucogalactan containing almost equal amounts of D-glucose and D-galactose residues. Throughout this research، Kefiran and Xanthan were added at concentrations of 3% (w/w flour basis) to two wheat dough samples to investigate the effects on the rheological and physical properties of French bread. Physicochemical properties of wheat and its flour were analyzed though Inframatic، the rheological of wheat dough by Farinograph، the stalingof bread by Instron texture analyzer apparatus. Results of Farinograph evaluation of the dough showed، adding of 3% level Kefiran and Xanthan led to a significant increase (p<0. 05) in the water absorption capacity، dough development time، dough stability in comparison with control، although the dough degree of softening after 10 and 20 minutes and Mixing tolerance index got decreased significantly (p<0. 05). Based on the results of staling tests done within the three times of: 24، 48 and 72 hours، it was characterized that an addition of levels of Kefiran 3% and Xanthan 3% to wheat dough، the rate of bread’s crumb staling decreased significantly (p<0. 05)، whereas the 3% xanthan sample had a lower rate of staling as well as higher hardness than the control samples. As a result، although Xanthan (like Kefiran) exerted a positive effect on the rheological properties of dough، but the hardness of breads in comparison with control and with samples containing Kefiran got increased.