03食品质地仪器测定PPT.ppt

;;;第三节 食品质地的仪器测定;第三节 食品质地的仪器测定;质构仪-TPA test;TPA is based on the recognition of texture as a multi-parameter attribute. For research purposes, a texture profile in terms of several parameters determined on a small homogeneous sample may be desirable. The test consists of compressing a bite-size piece of food two times in a reciprocating motion that imitates the action of the jaw and extracting from the resulting force-time curve a number of textural parameters that correlate well with sensory evaluation of those parameters;The mechanical textural characteristics of foods that govern, to a large extent, the selection of a rheological procedure, and instrument can be divided into the primary parameters of hardness, cohesiveness, springiness (elasticity), and adhesiveness, and into the secondary (or derived) parameters of fracturability (brittleness), chewiness and gumminess SZCZESNIAK, A. S. (1966). Texture Measurements. Food Technol., 20, 50, 55-58.;质构仪-TPA test;第三节 食品质地的仪器测定;Hardness(硬度);Brittleness, crunchiness, and crumbliness, which are a similar concept, can be measured as the ease with which the material fractures under an increasing compression load In general, the smaller the deformation under a given load, the lower the cohesiveness and the greater the ability to fracture of the product.;Adhesiveness黏着性，黏附性;Springiness（恢复性，弹性，回弹）;Cohesiveness凝聚性，黏聚性;Cohesiveness may be measured as the rate at which the material disintegrates under mechanical action. Tensile strength is a manifestation of cohesiveness. If adhesiveness is low compared with cohesiveness then the probe is likely to remain clean as the product has the ability to hold together. Cohesiveness is usually tested in terms of the secondary parameters chewiness and gumminess.;Gumminess胶黏性、胶着性;Chewiness（咀嚼性）;It should be understood that the same product cannot exhibit both chewiness and gumminess, unless as a solid it becomes a semisolid during sensory mastication. Such a transition is practically nev