Extracting Useful Information from Irregular and Irreproducible Mechanical and Other Signatures

  • Micha Peleg


The force-displacement curves of brittle (crunchy) foods are notorious for their irregular shape and irreproducibility. Nevertheless, they are still a record of successive failure events and therefore their jaggedness should not be treated as an artifact. The objectives of this communication are to present methods to characterize such curves, to demonstrate these methods capabilities and limitations, and to show how they can be used to evaluate the effect of moisture on the texture of cereal-based and other food products. Although the focus of this communication is on mechanical signatures, other types of signatures or records (e.g. acoustic) can also, at least in principle, be treated by the same or similar procedures. The mathematical principles on which the described methods were developed in other fields and several of them have been routinely applied in research and the design of engineering systems. They are discussed in great detail in the vast literature on the analysis of time series, chaos and fractals. The following will only describe their specific application, to food texture evaluation in our laboratory at the University of Massachusetts. No attempt has been made to provide a comprehensive literature survey on the subject or to cite and discuss the works of other groups which are active in the field and use similar or alternative techniques.


Water Activity Moisture Sorption Stiffness Measure Dimensionless Force Water Activity Level 
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  1. 1.
    Barrett, A. M., Normand, M. D., Peleg, M. and Ross. E. 1992. Characterization of the jagged stress-strain relationships of puffed extrudates using the Fast Fourier Transform and Fractal Analysis. J. Food Sci. 57:227-232 and 235.Google Scholar
  2. 2.
    Wollny, M. and Peleg, M. 1994. A model of moisture induced plasticization of crunchy snacks based on Fermi’s distribution function. J. Sci. Agr. Food. 64, 467-473.Google Scholar
  3. 3.
    Harris, M. and Peleg, M. 1996. Patterns of textural changes in brittle cellular cereal foods caused by moisture sorption. Cereal Chem. 73, 225 - 231.Google Scholar
  4. 4.
    Peleg, M. and Normand, M.D. 1995. Stiffness assessment from jagged force-deformation relationships. J. Texture Stud. 26, 353 - 370.CrossRefGoogle Scholar
  5. 5.
    Gerhards, Ch., Ulbricht, D. and Peleg, M. 1998. Mechanical characterization of individual instant coffee agglomerates. J. Food Sci. (in press).Google Scholar
  6. 6.
    Peleg, M. 1997. Measures of line jaggedness and their use in foods textural evaluation. CRC Crit. Rev. Food Sci. Nut. (in press).Google Scholar
  7. 7.
    Tesch, R., Normand, M.D. and Peleg, M. 1996. Comparison of the acoustic and mechanical signatures of two cellular crunchy cereal foods at various water activity levels. J. Sci. Food Agric. 70, 347-354.Google Scholar
  8. 8.
    Tan, J., Gao, X. and Hsieh, F. Extrudate characterization by image processing. J. Food Sci. 59, 1247 - 1250.Google Scholar
  9. 9.
    Rhode, F., Normand, M. D. an Peleg, M. 1993. Characterization of the power spectrum of force-deformation relationships of crunchy foods. J. Texture Stud. 24, 45 - 92.CrossRefGoogle Scholar
  10. 10.
    Kaybe, B.H. 1989. A Random Walk Through Fractal Dimensions. VCH, New York.Google Scholar
  11. 11.
    Kaye, B.H. 1993. Chaos and Complexity, Discovering the Surprising Patterns of Science and Technology. VCH, New York.Google Scholar
  12. 12.
    Peleg, S., Naor, J., Hartley, R. and Avnir, D. 1984. Multiple resolution texture analysis and classification. IEEE Trans. Pattern Anal. and Machine Intel. 6, 518-523.Google Scholar
  13. 13.
    Peleg, M. and Normand, M. D. 1993. Determination of the fractal dimension of the irregular compressive stress-strain relationships of brittle crumbly particulates. Part. Part. Syst.Charact. 10, 301-307.Google Scholar
  14. 14.
    Borges, A. and Peleg, M. 1996. Determination of the apparent fractal dimension of the force-displacement curves of brittle snacks by four different algorithms. J. Texture Studies 27, 243 - 255.CrossRefGoogle Scholar
  15. 15.
    Damrau, E., Normand, M.D. and Peleg, M. 1997. Effect of resolution on the apparent fractal dimension of jagged force-displacements relationships and other irregular signatures. J. Food Engng. 31, 171 - 184.CrossRefGoogle Scholar
  16. 16.
    Suwonsichon, T., Normand, M.D. and Peleg, M. 1998. Estimation of the mechanical properties of individual brittle particles from their bulk compressibility. J. Texture Stud. (in press).Google Scholar
  17. 17.
    Russ, J. C. 1994. Fractal Surfaces. Plenum Press, New York.Google Scholar
  18. 18.
    Ulbricht, D., Normand, M.D., Peleg, M. and Horowitz, J. 1994. Assessment of the crumbliness of individual fragile particulates from that of their assemblies. Powder Technology 81, 83 - 91.CrossRefGoogle Scholar
  19. 19.
    Ulbricht, D., Normand, M.D. and Peleg, M. 1995. Creating typical jagged force-deformation relationships from the irregular and irreproducible compression data of crunchy foods. J. Sci. Food Agric. 67, 453-459.Google Scholar
  20. 20.
    Ruelle, D. 1989. Chaotic evolution and strange attractors. Cambridge University Press, Cambridge, UK.Google Scholar
  21. 21.
    Peleg, M. 1993. Do irregular stress-strain relationships of crunchy foods have regular periodicities ? J. Texture Stud. 24, 215 - 227.CrossRefGoogle Scholar
  22. 22.
    Pickover, C.A. 1986. On the use of symmetrized dot patterns for the visual characterization of speech waveforms and other sampled data. J. Acous. Soc. Am. 80, 955-960.Google Scholar
  23. 23.
    DeRosier, B., Normand, M.D. and Peleg, M. Effect of lag on the symmetrized dot pattern (SDP) displays of the mechanical signatures of crunchy cereal foods. J. Sci. Food Agric. 75.Google Scholar

Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • Micha Peleg
    • 1
  1. 1.Department of Food ScienceUniversity of MassachusettsAmherstUSA

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