Crispness is another important quality factor of most fried food
products. Several texture changes occurred when moisture was
removed from the banana chips. The typical compression load-distance
curves of banana chips obtained for the different treatments
studied in the present work are shown in Fig. 5. At the beginning,
the compression force increased linearly as the compression increased
until the first set of cells fractured. The presence of air cells
in the crispy chip structure dropped the force after each fracture.
However, the compression force continued increasing as the chips
were compressed until the next set of cells fractured, which ended
in a drop in the force. This pattern is called a jagged force–deformation
(Peleg and Normand, 1995; Dogan and Kokini, 2007). In the
present work, different patterns of the jagged force–deformation
were observed depending on the frying conditions (Fig. 5). Coated
banana chips showed a higher breaking force than the control or
the high speed samples, indicating that the gums provided protection
against mechanical damage. Such protection against mechanical
damage of food has been observed in many films and coatings
including banana and mango films (Sothornvit and Pitak, 2007;
Sothornvit and Rodsamran, 2008).