Extracting Useful Information from Irregular and Irreproducible Mechanical and Other Signatures

Abstract

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.