Study of structure and flavour release relationships in low moisture bakery products by means of the acoustic–mechanical combined technique and the electronic nose

A combined acoustic–mechanical technique was employed to simultaneously characterise in uniaxial compression mode the texture properties of commercial toasted sliced breads and laboratory-made ones that were made by modifying the amount of sucrose in the recipe. Also an Image Analysis technique was used to describe the morphology of the gas cells. The analysis of the flavour release was performed by means of a commercial electronic nose system. Advanced techniques of multivariate statistical analysis were employed to get the maximum information from the proposed instrumental techniques. Some selected mechanical parameters and flavour release responses are dominant in discriminating sliced bread samples and both express similar information. The Regularised Discriminant Analysis output for the acoustic, mechanical and flavour release data was: Non Error Rate Cross Validated equal to 80.1% in the cross-validation mode. The NERCV % index is an estimation of the predictive potential of the model that was validated according to the leave one out (LOO) method. The LOO procedure removes each sample from the data set, one at a time. The classification model is rebuilt and the class of the removed sample is predicted by using the obtained model. By combining these instrumental characterisation methods, the result of the texture/aroma description of these cellular solids was improved.