Bread staling. IV. Electrical properties of the crumb during staling

A new technique for studying the staling of bread is described based on conductance and capacitance measurements on the isolated centre‐crumb. It is proposed that the observed changes (up to 17%) in the electrical properties are due to retrogradation of the starch as well as the changes undergone by the transforming protein. Moisture redistribution is thought not to play a significant role during staling of the crumb at temperatures of less than about 10 °C. At 36 °C the first‐order rate‐constant for the protein transformation was estimated to be 0.7 day −1 and 0.3 day −1 for the rate constant for retrogradation of the starch fraction of the crumb. At 0 °C, the protein transformation was insignificant and the rate constant for the starch change was 1.03 day −1 . The thickness of the gluten membrane surrounding the starch granules in bread was approximated to be less than 1 μm.