Week 5: Protein Aggregation and Gelation

Watching soy milk become tofu as a percolation event — the gel point as a moment in time, not a texture, and the Winter-Chambon criterion for it.

22 March 2027

Outline#

• Recap: Module 4 built a network from starch crystallites. This lecture builds one from aggregating protein particles instead — same idea of connectivity, a different molecule doing the connecting.
• Percolation, introduced as a threshold rather than a gradient: a dispersion of protein particles doesn’t gradually thicken into a gel, it crosses a critical connectivity and gels essentially at once.
• Locating the gel point with the Winter-Chambon criterion, and why the lecture insists on “a moment, not a texture” — the gel point is a structural transition you can date, distinct from how firm the gel ends up once fully set.
• Worked example: soy milk to tofu as the clearest kitchen case of watching a liquid cross its own gel point in real time.
• Bridging forward to Module 6: a structure that gels via percolation (protein network) versus one that resists flow without ever forming a true network (an emulsion) — two different routes to “won’t separate.”