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Physicochemical behaviour of starch-protein mixtures during low-moisture extrusion
Claudia is from Berlin (Germany) and completed her Master’s degree in Food Engineering at Berlin University of Technology. During her final two years she has undergone two Industrial Traineeships at CSIRO, Australia.
Extrusion cooking has become a highly important processing technology that is used to obtain a wide range of processed food products such as breakfast cereals, ready-to-eat snack products and pet foods. During extrusion processing, primarily dry powdered starchy and/or proteinaceous food materials are subjected to a combination of low moisture (10 to 30 %), high temperatures (up to over 150 °C), high pressure (up to 25 MPa) and mechanical shear leading to molecular transformation and a variety of reactions including starch dextrinisation and protein denaturation.
To facilitate the production of nutritious extruded food products, improved extruder and process control is necessary. Automation and control during extrusion is difficult due to non-standardised reporting of extrusion control parameters and non-linearities that occur in product characteristics during processing, which complicate the application of model systems. Therefore, further research with focus on different extrusion process parameters and their impact on different physicochemical reactions such as starch dextrinisation and protein hydrolysis as well as material properties including rheology and glass transition temperatures is required to get a better understanding of the material-process interaction and, thus, to enable optimisation of the extrusion process.