The aim of this paper is to produce spherical encapsulates of wheat gluten in a food-grade biopolymer for preparing sheared meat analogs, to prevent instant fibrilization of the gluten during a pre-mixing step. The hydrogel should release the gluten inside the Couette Cell, as a result of the higher temperature and shear in the process. Both sodium alginate and κ-carrageenan were used as encapsulants. Spherical particles of hydrogel-gluten mixtures were produced by means of a dripping method using an encapsulator. While the particle properties of κ-carrageenan surpassed those of alginate in terms of controlled release of the core, the particle production using the encapsulator was more complicated. With κ-carrageenan, a layer of oil on top of the cross-linking bath fluid, as well as through the outer orifice of a concentric nozzle were required to obtain a good sphericity of the particles. For the alginate particles the use of oil was not necessary. Gluten loadings of 7% w/w were achieved with 1.5% w/w alginate and with 2% w/w κ-carrageenan. The water content of the particles can be easily controlled by a subsequent partial drying step. A mixture of Soy Protein Isolate and particles was sheared in the Couette Cell. Controlled release of the gluten from the alginate particles was not achieved properly by temperature or shear. The controlled release of the gluten was achieved at the processing conditions only with κ-carrageenan. Some fibrilization was observed in the sheared product, but the macrostructure was not yet well developed. However, an optimization of the shearing process for the use of the particles may lead to an improved structure for the meat analogs.

We have demonstrated that application of simple shear flow and heat in a Couette Cell is a scalable process concept that can induce fibrous structural patterns to a granular mixture of plant proteins at mild process conditions. In particular, a Couette Cell device with 7-L capacity was employed for the production of structured soy-based meat replacers. A reduced factorial experimental design was used to find the optimum process conditions between two relevant process parameters (process time and rotation rate), while the process temperature remained constant at 120 °C. Fibre-structured products with high anisotropy indices were produced. Fibrousness is favoured at 30 ± 5 min and 25 ± 5 RPM. The up-scaled Couette Cell can be operated in higher industrial values and yield 30 mm thick meat replacers, which emulate meat. Besides, the study did not reveal any barriers for further upscaling of this concept. The flexibility in design allows production of meat alternative products with sizes that are currently not available, but could have advantages when aiming at replacement of complete muscular parts of animals, for instance, chicken breast or beef meat.