Investigating the Feasibility of using Scandinavian Agricultural Side Streams for the Development of Novel High-Moisture Meat Analogues
Abstract: Meat analogues are products that are supposed to resemble meat in terms of texture, flavour, and also sensory characteristics. They have recently become increasingly popular due to numerous issues related to health, religion, environmental impact and the growing number of vegetarians and vegans. Due to this reason, many plant-based protein materials, including grains, legumes, microalgae, and mushrooms, are increasingly being scientifically explored. Plant-based proteins are now much more widely available on the market, offering customers more options to meet their nutritional needs. Extrusion, an industrial process method, accomplishes this by structuring plant-based components through vigorous heating and mixing in a twin-screw extruder. In high-moisture extrusion, the ingredients melt during the process, followed by a cooling step that limits expansion. Lamellar shear flow causes the structure development during cooling. Raw materials in the form of protein concentrates, and isolates are commonly used for texturizing meat analogues. Thus, understanding the effects of the various operating parameters of the process on the raw materials allows the development of better products and processes. In this thesis, we have investigated the extent to which it is possible to use Scandinavian agricultural side streams, i.e., proteins derived from hempseed and rapeseed press cake, and oat fibre residue, for the development of novel high-moisture meat analogues (HMMA). In addition, our aim was to comprehend the fundamental operation of high-moisture extrusion cooking (HMEC) through our research. By understanding the protein properties along with the changes that occur during processing and cooking could allow the control and creation of good fibrous structures similar to meat. Complicating matters further is the fact that protein materials have different compositions and behaviours that depend heavily, for example, on the plant species and how the proteins are extracted.Novel HMMAs with promising textural properties were successfully developed by co-extrusion of protein materials from hempseed and soy (HPC+SPI), rapeseed and yellow pea (RPC+YPI), hempseed and oat fibre residue (HPC+OFR), hempseed and wheat gluten (HPC+WG), and hempseed and chickpea (HPC+CPC). HPC, RPC and OFR were proven to be excellent materials for HMMA production due to their pleasant texture. HMMA made from a 50:50 blend of rapeseed protein concentrate (HPC), and yellow pea isolate (YPI) had a promising amino acid composition. Sensory evaluation showed that HMMA using protein combinations from hempseed and wheat gluten (HPC+WG), as well as hempseed and chickpea (HPC+CPC) would have a bright future. The differences in protein materials had a significant impact on the properties of HMMAs. It was interesting to know that even when using the same raw material, differences in the physical and textural properties of the HMMAs could be found depending on the protein composition and the way the protein was processed as well as the extrusion parameters. In the experiments presented in this thesis, it was found that the target moisture content, barrel temperature and the screw speed, had the greatest influence on the extruder process and product quality. A high-shear screw configuration resulted in stronger fibres and greater texturing than a low-shear screw configuration.Further studies are needed to completely comprehend the intricate extrusion process and formulation matrix, including the nutritional content, formation of fibre, and customer acceptance of the newly created HMMA.
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