36D-7 |
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L. SAMUEL, H. Dogan, and J. L. Kokini. Dept. of Food Science, Rutgers, The State Univ. of New Jersey, Center for Advanced Food Technology, 65 Dudley Rd., New Brunswick, NJ 08901-8520 The composition and morphology of food products influence the quantitative measures of textural properties derived during their mechanical deformation. The focus of textural analysis of two-phase dry food products like cream or fruit-filled snack bites, is to differentiate between the textural properties of each phase (crust and filler). Our objective was to identify test methods and conditions which can objectively differentiate between the textural characteristics of the different phases of such two-phase products. Compression and penetration tests were done to evaluate the extent of textural information that can be obtained for the crust and filler phases. Test parameters studied were probe speed (1-3 mm/sec) and probe diameter (0.5-100 mm). A robust and operator independent macro was developed to analyze the force-deformation curves for various texture parameters. Uniaxial compression failed to deconvolute the properties of the shell and filler phases. During compression, the sealed edges of the crust collapsed, preventing a reliable measurement. The shape of the conical probe resulted in breakage of the sample before penetration. Moreover, as the samples break instantaneously when the probe tip contacts the surface, the results were point specific and did not describe the mechanical properties of the sample as a whole or of the phases themselves. The punch probe was able to differentiate between the resistances to mechanical deformation offered by the two phases. The developed macro identified differences between the mechanical properties of the two phases which was then used to generate useful, reliable information related to their textural properties. Mechanical measurements with different probes showed the importance of selection of appropriate test methods and conditions for textural analyses of two phased products. The introduction of operator independent decision-making tools in the macro made the analysis robust and reliable.
Session 36D, Food Engineering: Rheology
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |