Relative hardness profiles measurements

Most mechanical tests developed for fats are empirical in nature and are usually designed for quality control purposes, and they attempt to simulate consumer sensory perception (3, 4). These large-deformation tests measure hardness-related parameters, which are then compared with textural attributes evaluated by a sensory panel (3, 5). These tests include penetrometry using cone, pin, cylinder and several other geometries (3, 6-12), compression (13), extrusion (13, 14), spreadability (15, 16), texture profile analysis (2), shear tests (13), and sectility measurements (14). These methods are usually simple and rapid, and they require relatively inexpensive equipment (3, 4, 17). The majority of these tests are based on the breakdown of structure and usually yield single-parameter measurements such as hardness, yield stress, and spreadability, among others (4, 17-20). The relationship between these mechanical tests and the structure of a fat has, however, not been established. The ultimate aim of any materials science endeavor is to examine the relationship between structure and macroscopic properties. 

Lastly, it is commonly assumed that the relaxation rate of all solute atoms is consistent, which is not the case for multiple compounds in a single sample (e.g. metabonomics). Calibrations must be applied to any standard database for identification based on relative rates of relaxation, and therefore intensity of peaks. Different functional groups in the same molecule can have different spin-lattice relaxation rates as would more flexible regions of large molecules. For extremely accurate measurements the calibration of signal loss is also frequency dependent (i.e. distance to carrier position is proportional to intensity variation) due to the profile of the hard pulses. 

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