Continuous microwave-assisted extrusion for high moisture texturized foods: A feasibility study

Abstract

This study demonstrates a technical scale set-up for microwave-assisted extrusion of high moisture, texturized food systems. The set-up has been evaluated in a stationary study regarding the correlation of microwave tuner position and gap with the reflected microwave power and the product temperature, respectively. On that basis, a casein-based model food system has been plasticized by continuous microwave extrusion. The product outlet temperature and chemical composition have been investigated with varying screw speeds and power inputs.The stationary study resulted in specific tuner positions, giving an area of desired process parameters. This area was successfully transferred to a continuous product application, where desired gel-sol transition was achieved. With increasing power input, the product temperature increased, while it decreased with increasing screw speed and constant power input. The fat, protein, and dry matter content of the casein-based model system did not differ significantly throughout all trials. Industrial relevanceMicrowave heating is a promising alternative heating method for food applications. Within microwave extrusion it shows high potential for upscaling applications whilst maintaining a homogenous temperature distribution throughout the product. Moreover, microwave technology offers high efficiencies and the possibility to use green energy sources. Furthermore, the space saving design and easy application provide high potential for scale-up.