THE ACOUSTIC IMPULSE-RESPONSE OF APPLES IN RELATION TO INTERNAL DAMAGE AND IN RELATION TO APOPLASTIC PH

Product texture can be described by tissue elastic properties and tissue firmness.
The aims of this research were 1) to demonstrate the ability of the acoustic impulse-response technique to non-destructively detect internal damage of apples and 2) to examine if the acoustic technique depends on biochemical changes in the cell walls of apples.
Apples were subject to microwave treatment to obtain fruit with internal damage.
They were measured by means of MT-firmness and acoustic impulse-response technique.
Results before and after to microwave treatment were compared.
The apoplastic pH and the acoustic impulse-response of apples were measured during development and storage of the fruits.
With MT-firmness no significant difference was found between apples before microwave treatment and after.
With the acoustic impulse-response technique highly significant differences were found between the control and the measurement after microwave treatment.
The possible relation between stiffness and apoplastic pH is shown by a high correlation between the two parameters during storage.
It can be concluded that the acoustic technique gives clear results on identifying internal damage in apples.
There is indication that the acoustic impulse-response technique indeed depends on cell wall changes.

V International Postharvest Symposium

S. Landahl, J. Gonzalez, V. Van Linden, J. De Baerdemaeker

Malus domestica, non-destructive, food texture, cell wall, degradation, stiffness, softening

https://doi.org/10.17660/ActaHortic.2005.682.188