Microstructure, textural and sensorial properties of durum wheat bread as affected by yeast content

In this study, breads varying in yeast content and therefore leading to distinct cellular structures are investigated. Firstly, X-ray microtomography is used to characterize not only the final cellular structure, but also the process of development of microstructure during the fermentation stage. With μCT, image analysis of the full 3-D microstructure, measuring the size, shape, networking/connectivity and distribution of various phases was possible. These measurements represent the full 3-D microstructure, which is not always possible by 2-D image analysis using statistical techniques. Secondly, the textural properties of the baked bread were obtained by compression tests and finally, the sensorial quality of the final product is also evaluated and correlated with the above properties. Results showed that an increase of the yeast content increased the percentage volume of pores and decreased the force required for compression of the bread sample and the tenacity. Moreover, a larger quantity of smaller sized pores led to a firmer bread structure. Regarding the sensorial properties, none of the investigated microstructural parameters were significantly correlated with the overall quality of the bread. In fact, the overall quality was more strongly affected from other parameters such as odor and appearance attributes.

► Bread varying in yeast content led to distinct cellular structures. ► An increase of the yeast content increased the percentage volume of pores. ► An increase of the yeast content decreased the force required for bread compression. ► The microstructural parameters were not correlated with the bread overall quality. ► The overall quality was affected from parameters such as odor and appearance.