TEXTURE AND STRUCTURE OF CRISPY‐PUFFED FOOD PRODUCTS PART II: MECHANICAL PROPERTIES IN PUNCTURE

Abstract

ABSTRACT A puncture test was used to describe the mechanical and textural behavior of crispy‐puffed food extrudates. Four criteria were identified from the force‐time curves: (1) the average puncturing force, F m , (2) the spatial frequency of structural ruptures, N wr , (3) the average specific force of structural ruptures, f wr , and (4) the crispness work, W c . The discriminating power of these criteria was shown through the effects of moisture content and recipe composition in the extrusion‐cooking process. Relationships between puncture criteria were also studied. The effect of water activity showed that the force related criteria described well the mechanical behavior of expanded extrudates.