Why do boiled potatoes not shrink?

Boiled potatoes actually do shrink when cooked, although it's not always as noticeable as with other vegetables. Here's why:

* Starch gelatinization: Potatoes contain starch, which absorbs water during cooking. This gelatinization causes the potato cells to swell, making the potato larger.

* Cell wall breakdown: However, as the potato cooks, the cell walls weaken and break down. This allows some of the water to escape, causing the potato to slightly shrink.

* Pressure differences: The pressure inside the potato cells is higher than the pressure outside during cooking. This pressure difference also contributes to water loss and shrinkage.

Why it might not seem like they shrink:

* The starch gelatinization effect: The expansion caused by starch gelatinization often outweighs the shrinkage from water loss.

* Potato variety: Different potato varieties have varying starch content and cell wall structures, affecting their shrinking behavior.

* Cooking method: Boiling tends to cause less shrinkage compared to other methods like roasting or frying, where more surface area is exposed to heat.

In conclusion, boiled potatoes do shrink, but the effect is less dramatic than with other vegetables due to the combined effects of starch gelatinization, cell wall breakdown, and pressure differences.