Understanding the mechanisms associated with quality creation in protein-rich plant-based aerated food materials during processing

考虑到动物农业食品链对环境的影响，创新型食品公司正在转向资源密集度较低但营养丰富的来源，并开发工艺，从未充分利用的植物中释放富含蛋白质成分的潜力。挤压是一种高通量工艺，具有控制食品设计的灵活性，并将富含植物蛋白的成分装入食品中。挤压也是一种有效的方法，将气泡改造成富含蛋白质的基质，从而将致密、坚硬的材料转化为更轻、更美味、更吸引人的形式，显著提高食品质量。然而，富含蛋白质的充气食品在超市货架上很少见，因为人们对富含蛋白质的食物基质中的气体动力学知之甚少，尤其是挤压过程中的气泡力学（即成核、生长、聚并、崩溃、凝固）。我在食品曝气方面的背景使我能够研究富含植物蛋白的食品加工过程中的结构创造。

Given the environmental impact of the animal agri-food chain, innovative food companies are shifting to less resource-intensive yet nutritious sources, and developing processes to unlock the potential of protein-rich ingredients from underutilized plants. Extrusion is a high throughput process with the flexibility to control food design and to load plant protein-rich ingredients into foods. Extrusion is also an effective means of engineering bubbles into a protein-rich matrix, thereby converting dense, hard materials into lighter, more palatable and appealing forms, significantly enhancing food quality. However, protein-rich aerated foods are rare on supermarket shelves because very little is known about the dynamics of gases in protein-rich food-matrices, especially bubble mechanics during extrusion (i.e., nucleation, growth, coalescence, collapse, setting). My background in food aeration has uniquely positioned me to investigate structure creation during processing of plant protein-enriched foods. My long term goal is to understand how food structure is tailored during processing of high-quality, nutritious foods for future food sustainability and security, and train my HQP with appropriate skills for an evolving food system. My objectives are to (1) Elucidate the role of proteins in bubble nucleation and rheological properties of the matrix surrounding them during extrusion using a non-destructive ultrasonic technique, (2) Resolve the link between glass transition and bubble collapse for protein-enriched extrudates using differential scanning calorimetry and cross sectional and volumetric imaging techniques, and (3) Examine the role of gas incorporation in aeration of protein-rich expanded foods made from cereals and pulses, using X-ray microtomography. The anticipated outcomes of this program are: (1) acquisition of foundational knowledge on processing conditions, rheology and food formulation interactions, so as to devise strategies to optimize structure at elevated protein concentrations, and (2) establishment of gas assisted extrusion as a novel technique for mitigating structural impairment caused by protein enrichment in extruded foods. Additionally, by establishing a sound understanding of bubble dynamics in protein-rich matrices, I will help processors formulate healthier foods with novel structures (e.g., plant protein-rich ingredients, snacks, pasta products, etc.). Accordingly, my program will potentially increase Canadian market share in the lucrative global plant protein and snack food industries, and expand employment opportunities for the 9 HQP who will be trained in this program. Ultimately, investigating the factors driving changes in bubble dynamics in aerated soft materials during processing will enable us to advance principles that can also be applied to understand the properties of various polymers and cellular foams.