NOVEL STRUCTURING AND LAYERING ADDITIVE 2D MANUFACTURING PROCESS FOR WHOLE CUT FISH ANALOGS
Creators: name: Steck, William
Publisher: name: University of Massachusetts Amherst
Year: 2025

The consumption and demand for plant-based foods, especially plant-based meat alternatives, has increased rapidly. This rapid increase has come from many reasons, such as lifestyle choices, environmental concerns, and animal welfare. While extensive research and testing has been done to replicate whole cut plant based meats such as chicken, beef, and pork, plant-based whole cut fish lacks nutritious and texturally appealing options. With this gap in the market, finding a method that both matches the nutrition of fish and replicates the unique protein structure is necessary. Current scalable processing methods fail to mimic the micro and macro structure of fish protein. While conventional 3d printing based additive manufacturing processes have the potential of creating plant based whole cut fish analog with texturally similar products while also maintaining nutrition profiles (mainly protein content), the processes however are limited by the potential towards scalability. Considering the laminated nature of the whole cut fish meat, extrusion based coating based processes may provide a novel and promising solution for the make of whole cut fish analog with potential scalability. In addition, the unique and controllable hydrodynamics of the free surface coating flow may also allow for the desirable microstructure protein alignment that mimic the fish muscle texture. Therefore, the objective of this thesis is to evaluate the feasibility of a novel slot coating-based 2D additive manufacturing for the making of plant protein-based fish analog with a focus on printability, buildability as well as internal structure formation ability. To achieve these objectives, a multistage approach was utilized, involving the construction of a novel slot-coating-based 2D additive manufacturing system, system characterization, and the development of plant-protein-based bioinks. Initial system characterization employed a simple solution of gelatinized potato starch as a model bioink. Comprehensive parametric studies were conducted to evaluate the impact of key processing parameters, such as bioink extrusion rate and printing rate, on the printability of the model bioink. A suitable processing window was identified based on the macroscopic structural integrity of the printed layer, and a phase diagram was constructed. With the system fully characterized, plant-protein-based bioinks containing additives like polysaccharides and insoluble fibers were further examined. It became evident that printability, buildability, and operational parameters were highly dependent on the rheological properties of the bioinks. To gain deeper insight into the internal structure formation using this novel 2D manufacturing approach, stacked bioink layers were fabricated, cooked, and then observed under confocal microscopy to analyze the internal structure. Texture profile analysis was also conducted to compare the bioinks' texture with that of real fish meat. Confocal microscopy results revealed that this manufacturing approach enables fiber alignment within the protein structure, closely mimicking the fibrous structure of fish meat. Additionally, texture profile analysis showed that bioinks with specific protein concentrations and additives successfully replicated the textures of fish meat. This thesis demonstrates that combining this innovative production method with optimized protein bioinks offers a promising pathway for producing improved plant-based fish analogs.