FRACBE · Characteristics of Fracture Behaviour of Food Materials

Final Activity Report Summary - FRACBE (Characteristics of Fracture Behaviour of Food Materials)

Until today, the food industry usually applies trial-and-error variations on traditional processes and ingredients, when developing new products. Food behaviour originates from the structure present in food materials and the interactions within and between structural elements. By using the right selection of ingredients and a suitable processing, food industry manufactures products with more or less the desired (in-mouth) behaviour, but how this relates to structure and fracture properties is still poorly understood. Structure and fracture properties are especially important because a consumer perceives a product through its exposed surface on the fracture plain. Exposure of material domains (fat exposure) allows their contribution to the textural performance of a product, but it may also open compartments in which flavours are concentrated, allowing their release. Hence both texture and taste are affected by fracture. The objective of this project was to increase the understanding of structure and fracture behaviour of semi-solid foods (cheese-like) with the aim (1) to improve their sensory quality and (2) to contribute to design guidelines for biopolymer food matrices with desired fracture properties. The ultimate goal of the fellowship was to develop and implement analytical capabilities for the characterisation of physico-chemical properties of soft-solid biopolymer based materials and their structure originated fracture behaviour. The project was divided into four phases: In phase 1, after executing a thorough literature search and stakeholders interviews within the company, the findings were reported and implemented in the project plan. Fracture behaviour is confirmed by a literature report as an important food material property linked to sensory performance. The analysed data also show the complexity of cheese and the influence of multiple interactions between the components (fat globules, protein matrix, water content, process parameters, ...) on the sensory properties. The report confirms the relevance of this project for Friesland Foods. In phase 2, the research facilities were implemented on site (a) by technology transfer from SIK (Sweden) for microscopy observation of sample under deformation; (b) by developing methods for (cheese) sample characterisation. We showed that the cheese fracture itself does not release the internal fat globule content on the new surface generated. Liquid fat release is due to other factor such as cheese compression. In phase 3, further development of new analytical capabilities was implemented. CARS microscopy (Coherent anti-Stoke Raman spectroscopy) were tested on cheese and showed the benefit of this technique to image the cheese surface without disturbing the matrix, however, not apply in this project due to time constraint. External consulting and internal expertise allowed developing a new image analysis method to quantify the degree of particles (e.g. fat particles) on surface fracture. In phase 4, the new image analysis methods was used to test the hypothesis that different fat globule organisations in the matrix (e.g. random / regular distance between the fat globules or clustered fat globules) will give rise to different degrees of fat exposure on the new fat surface generated. Experiment on cheese showed that only one type of structure (random / regular) is generated during the cheese process so other food models (gelatin or carrageenan) were used to obtain random / regular or cluster arrangements of the fat particles. Model fractures in regular structure were also generated and used as reference. We showed that at high fat content in the matrix, the fat percentage on the fracture surface tend to a same value whatever is the fat organisation (random \ regular or cluster). At low fat content (10 %), although the clustered fat particles organization seems to expose more fat on the fracture surface, however, the number of experiments does not allow performing statistical analysis and further experiments is needed to confirm or infirm.

Data: CORDIS, © European Union