Mechanical properties of white and green asparagus: changes related to modifications of cell wall components

The changes of texture that take place in white and green asparagus during storage and cooking are, in large part, determined by the composition and structure of the cell walls. Several instrumental methods have been applied to three sections of the spears to investigate the physico-chemical properties that contribute to the values of texture. Cutting the spears with a razor blade is the most appropriate method for quantifying and comparing the texture of white and green asparagus and, among the different parameters that can be calculated from the curves registered during asparagus cutting, strength and toughness have been used for determining changes of texture. Post-harvest storage caused an increase of texture mainly located in the lower portions of the white spears. The process of toughening also affected the lower section of the green spears, but to a lesser extent. Cooking resulted in a softening, mostly in the apical section of the stem. Additional information about the physico-chemical properties of different plant tissues has been obtained by applying a tensile test to the internal and external tissues separated from asparagus sections.