347 Determining critical wheat dough mixing characteristics using a conventional mixer.

C. H. HWANG and S. Gunasekaran. Biological Systems Engineering Department, University of Wisconsin– Madison, Madison, WI 53706.

To determine wheat dough characteristics while mixing using a Hobart mixer with a pin-type attachment, power consumption profiles were measured over 20 min by a current transducer and a data logging system. Experimental variables were flour quantity (500, 1000, and 1500 g of dry wheat flour), mixer speed (low and high), and water content (43, 45, 47, or 48% wet basis). The power consumption profiles were evaluated by spectral analysis and moving average determination to reduce noise signals in the original profiles. Amplitude and phase angle data (by the spectral analysis), and averaged power consumption trend (by the moving average determination) were calculated. Peaks in power consumption profiles were located to determine the optimal mixing time. The optimal mixing times were then compared to elastic and viscous moduli measured using a dynamic rheometer (ModelCVO, Bohlin, Cranburry, N.J.) to assure the maximum strength of wheat dough at the optimal mixing time. Optimal mixing times of various doughs ranged from 5.7 to 8.0 min. A clear maximum peak was not observed at lower speeds due to insufficient mixing intensity. Low and high quantities of flour sample required longer mixing times than medium quantity of samples. The optimal mixing time increased with both lower and higher moisture contents. The dough with 47% moisture content required the shortest mixing time. Based on these results, on-line optimization of dough mixing time could be possible for the actual manufacturing precess using a conventional mixer with recording capability.