Prediction method of CO₂ production from electrical resistance of bread dough measured with a simple electrical...

Novel devices were created to monitor CO₂ production in dough fermentation. Three devices were made with probes of 15 mm, 40 mm square, and needle types, connected to a multimeter. Dough samples (0.5%, 1.0%, and 1.5% yeast) were filled in tailor-made container for fermentation and evaluated. Ratios of CO₂ were predicted from the electrical resistance of the dough, because of dielectric characteristics of CO₂ and dielectric theory. As fermentation progressed, the dough was expanded by holding of CO₂, the resistance rapidly increased in the early stage and gradually increased in the late stage, in all cases. The production of CO₂ was well estimated with respect to the yeast content. The comparisons of the predicted and experimental volume ratios showed similar patterns except for only one type (the 15 mm square). It was concluded that the electrical method could be an efficient alternative to the volumetric method to measure CO₂ production.