| Abstract: | The jaggedness of the compressive force-displacement relationship of cheese balls®, cocoa puffs® and peanut butter crunch® particles at various moisture contents was determined in terms of their apparent fractal dimension, and the mean magnitude of the power spectrum of their normalized residuals. The plots of these measures versus moisture contents had a characteristic sigmoid shape very similar to that of the corresponding sensory crispness and crunchiness vs moisture content relationships. This close similarity suggests that the jaggedness of the force-displacement relationship is a manifestation of the same failure events that produce the crispness or crunchiness sensation. (In the context of the tested products the two terms, crispness and crunchiness, were found to be synonymous.) In all three products moisture toughening could be clearly detected instrumentally but only in two there was an unambiguous corresponding increase in the sensory hardness scores. This indicates that at least in certain cereal products moisture toughening can be perceived simultaneously with brittleness loss. |
