Agri Kultuur June / Junie 2018 | Page 14

Engineering and Packaging IVV, in Germany. “But texture, juiciness, and bite—this is difficult.” To get a more fibrous, meat like texture from plant-based protein, Osen worked with other European Union researchers to develop a way to stretch globular plant proteins into strings and to encourage them to cling together into fibres. The project, called LikeMeat, targeted meat alternatives that were satisfactory enough to replace meat used in chicken nuggets, for example, but might not be meaty enough to replicate a fine steak. The method uses a technique known as high-moisture extrusion. Operators pour water and powdered proteins, often soy or yellow pea isolates, into a machine with two long, intertwined screw like shafts extending through controlled temperature zones. The temperature control allows the mixture to be heated as the screws mix and knead the ingredients traveling down the chamber. The plant proteins unfold, thanks to the heat, and align in the direction of the flow as they move through the screw. Then, at the end of the extruder, a cooling die causes the mixture to solidify and develop a fibrous texture. A final step in the process shapes the mixture into strips, crumbles, or other forms. Details about how the processing parameters and protein source impact the final product texture are under wraps. But Osen and his colleagues have experimented with boutique proteins derived from locally grown crops like peas, lentils, and lupin to produce vegetarian burgers, schnitzel, and meaty pasta sauce. Keshun Liu, a research chemist at the U.S. Department of Agriculture’s Agricultural Research Service, and Fu-Hung Hsieh, a professor of bioengineering and food science at the University of Missouri, have also worked to develop this method, and their research shows that disulfide bonds formed between denatured soy proteins account for the fibrous texture. Both Osen and Hsieh are involved with companies producing alternative meat products using high-moisture extrusion. In Germany, Osen says, there’s an interest in eating less meat, yet there are fewer options on grocery store shelves than in the U.S. The California-based food producer Beyond Meat licensed Hsieh’s high-moisture extrusion process, and built a plant in Columbia, Mo., near the university. The company’s chicken and ground beef are already available in some stores. Food writer and cookbook author Mark Bittman, in a column for the New York Times, High-moisture extrusion of soy powder, wheat gluten, and starch creates strips with a fibrous texture like meat, as in these imitation chicken strips. Image Credit: Keshun Liu. AgriKultuur |AgriCulture 14