Evaluation of the crumb staling perception threshold = Valutazione della soglia di raffermamento della mollica di pane

Bread crumb staling has been studied using crumb samples produced according to a standardised procedure. Crumb staling has been evaluated during storage at 20°C with constant moisture, by measuring the elastic modulus and the colour difference ΔE. Results show that elastic modulus and ΔE values can be satisfactorily described by the Avrami model (r = 0.994 and r = 0.970, respectively). These data, however, do not provide any information about the degree of acceptability of the product by the consumer. Crumb staling has been therefore sensorily evaluated by a trained panel. A series of triangular tests has been carried out to identify the sensory perception threshold for staling. The threshold was reached after about 11 hours storage time. The sensory perception threshold test has been then repeated; in this second test the fresh sample was absent, and the reference was just a mnemonic one. This test gave a perception threshold of less than 9 hours storage time.