Renggli Damian, Doyle Patrick S
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Soft Matter. 2025 Jan 22;21(4):652-669. doi: 10.1039/d4sm00687a.
The impact of animal-based food production on climate change drives the development of plant-based alternatives. We demonstrate the use of colloidal thermogelation on a real nanoemulsion system to create structured gels that could be of interest for thermo-mechanical processing of next-generation plant-based food applications. We use a commercial pea protein isolate (PPI) without further purification to stabilize a 20 vol% peanut oil-in-water nanoemulsion at pH = 7 by high-pressure homogenization (HPH) and demonstrate the temperature induced gelation behavior of the nanoemulsion as a function of the HPH processing parameters. Bright-field and laser scanning confocal fluorescence microscopy reveals a diverse microstructure of the aqueous PPI dispersions, with a large amount of insoluble protein particles, cell-wall debris particles, and lipid inclusions. Sedimentation of particulates is prevented by HPH treatment and leads to a loss of the dispersion's thermogelation properties. The non-gelling PPI dispersion stabilizes nanoemulsions and the insoluble components of the PPI dispersions persist throughout the HPH processing. We perform a systematic rheological investigation of the effect of HPH processing on thermogelation and demonstrate that the number of HPH passes and HPH pressure control the average nanoemulsion droplet size measured by DLS at a 90° scattering angle. We show that the droplet size defines the final gel strength with a strong inverse dependence of the elastic modulus on droplet size. Furthermore, processing can lead to heterogeneously structured gels that yield over a large strain amplitude range.
基于动物的食品生产对气候变化的影响推动了植物性替代品的发展。我们展示了在实际的纳米乳液体系中使用胶体热凝胶化来制备结构化凝胶，这可能对下一代植物性食品应用的热机械加工具有重要意义。我们使用未经进一步纯化的商业豌豆蛋白分离物（PPI）通过高压均质化（HPH）在pH = 7的条件下稳定20体积%的水包油型花生油纳米乳液，并展示了纳米乳液的温度诱导凝胶化行为与HPH加工参数的关系。明场和激光扫描共聚焦荧光显微镜揭示了水性PPI分散体的多样微观结构，其中含有大量不溶性蛋白质颗粒、细胞壁碎片颗粒和脂质内含物。通过HPH处理可防止颗粒沉淀，并导致分散体热凝胶化性能的丧失。非凝胶化的PPI分散体稳定了纳米乳液，并且PPI分散体的不溶性成分在整个HPH加工过程中持续存在。我们对HPH加工对热凝胶化的影响进行了系统的流变学研究，并证明HPH的通过次数和HPH压力控制了通过动态光散射（DLS）在90°散射角下测量的平均纳米乳液液滴尺寸。我们表明液滴尺寸决定了最终的凝胶强度，弹性模量与液滴尺寸呈强烈的反比关系。此外，加工可导致在大应变幅度范围内屈服的非均匀结构化凝胶。
