Poaching an egg is a great example of how protein denaturation works in the kitchen. A perfectly poached egg should have a tender opaque egg white that hides a runny egg yolk. To achieve this, the egg is first strained in a fine mesh strainer for a few seconds to eliminate any loose egg whites; this will help create a better-shaped poached egg. A splash of lemon juice adds the acidic pH that helps the egg proteins denature before it goes into a simmering water bath for the final stage of protein denaturation. The colorless egg white protein will change from transparent to a bright white opaque color.