103 The influence of additives and processing parameters on bread crumb image texture features using a factorial design.

P. CROWLEY (1,2), H. Grau (1,2), and E. K. Arendt (1). (1) Department of Food Technology and (2) National Food Biotechnology Centre, University College Cork, National University of Ireland.

The 3-dimensional structure of a food is characterised by the organisation of its molecular, microscopic and macroscopic components. In the same way that baking characteristics are influenced by the inclusion of additives or variation of processing parameters, so too are features of the bread crumb grain. In this study a Plackett-Burman Factorial Design was used to analyse the main effects of: fat, emulsifiers, and increased mixing time on calculated bread crumb image texture features. Bread was prepared according to a standard procedure. Bread slices were analysed two hours after baking using an in-house image analysis system developed from Jandel SigmaScan Pro™ and Microsoft Excel™. Image characteristics were determined for each bread type. Each bread type produced a characteristic image texture profile. Addition of emulsifiers had the most pronounced effect on the bread being the main effect on the majority of features. Increased mixing time was the main effect on total cell area, causing it to decrease significantly. Increased mixing time had a significant effect on increasing the total number of cells detected, decreasing the mean cell area, increasing the number of small cells and decreasing the number of cells larger than 4 mm(^2). Addition of fat to the bread had a significant effect on cell shape, causing a decrease in roundness; and on cell size, causing the mean cell area to increase. In conclusion, it was shown that image analysis in conjunction with a factorial design is an excellent tool for the determination of the main effects produced by additives and processing conditions on bread crumb grain characteristics.