Textural properties of fruit affected by experimental conditions in TPA tests: an RSM approach

P>Texture profile analysis (TPA) is widely used to assess the textural properties of fruit. However, test parameters may potentially affect TPA results. This work studies the influence of the degree of deformation and crosshead speed on the mechanical parameters of apple measured by TPA. In this study, the degree of deformation ranged from 5% to 17.8% and the crosshead speed from 10 to 90 mm min-1. Eight parameters were extracted from the analysis of force-displacement and force-time curves. For each parameter, the mean value and the coefficient of variation (CV) were examined. A central composite design that simultaneously takes into account both input variables, the degree of deformation and crosshead speed, was implemented. It appears that the linear and the quadratic effects of the degree of deformation make it the major variable. However, neglecting the effects (linear and quadratic) of the crosshead speed might be disastrous since they significantly affect parameters such as cohesiveness, gumminess and work 2. Moreover, the CV of hardness 1 depends mainly on the interaction between the degree of deformation and crosshead speed.