Proofing of bread dough assisted by ohmic heating

Proofing of bread dough was studied under ohmic heating for a target temperature of 35 degrees C. An experimental device based on PLC monitoring was developed to study the effect of heating rates and voltages on the proofing process. Conventional and ohmic heating-assisted proofing were compared; the results showed that the process itself had no impact on the proofing when identical heating rates (0.065 degrees C. min(-1)) were used. However, increasing the heating rate could significantly reduce the time needed to reach an expansion ratio of 3 (from 122 min during conventional proofing to 65-70 min during ohmic heating in the range of 1-10 degrees C-min(-1)). This was due to the shortening of the lag phase at the beginning of proofing (from 58 min during conventional heating to 20 min at 10 degrees C. min(-1) in ohmic heating). Results also showed that the voltage intensity had no significant effect on the proofing kinetics in the range of 50-150 V. The evolution of expansion ratios with proofing time could be fitted by a Gompertz model with a very high accuracy (R-2 > 0.999) (C) 2016 Elsevier Ltd. All rights reserved.