Effects of enzyme-resistant starch obtained from rice starch by autoclaving-retrogradation method on the rheology of bread dough and some chemical properties of bread

This study was aimed to investigate the effects of enzyme resistant starch (ERS)which is rapidly growing product in recent years obtained by autoclaving-retrogradation (AR) method, on the rheological properties of bread dough and some chemical properties of bread. In pure rice starch (PRS), while there was not ERS found at the beginning, 0.57% ERS was occurred after AR application. moisture, ash and total starch content of AR applied ERS (A-ERS) were found as 8.74%, 0.50%, 70.82% respectively. A-ERS was added in to wheat flour at 0%, 2%, 4% and 6% levels replacement with wheat flour. Effects of A-ERS on dough rheological properties was evaluated by using amylograph, Kieffer dough and gluten extensibility rig (KER) and Chen-Hoseney Dough Stickiness Rig tests (CHT). The lowest amylograph peak viscosity (782 B.U.) was observed when A-ERS was added at 6% concentration and the maximum force (Rmax) measured with KER was shown the highest value as 65.96 g by the addition of 2% A-ERS. The extensibility increased with the addition of 4% and 6% A-ERS while at 2% addition level it was given the similar values with control sample. CHT tests showed that inclusion of 2% A-ERS did'nt cause any significant change on the stickiness, work of adhesion and dough strength but significant increase on these parameters were observed as the level of A-ERS increased from 2 to 4 and 6% respectively. The amount of resistant starch present in the chemical composition of the bread increased proportionally with the addition rate of A-ERS. As a result; RS was occurred with AR application, substitution at 2% of A-ERS gave rheological values at least as good as the control sample. However, in order to achieve significant dietary fiber increase in bread, it was concluded that A-ERS should be added at least 6% level. Thus it can be suggested that A-ERS can be used as a valuable ingredient to enhance the functional properties of bakery products.