It’s fish for dinner tonight (actually some very nice looking whole trout I found at the fish market), which brought another of lemon juice’s many uses to mind (albeit non-bakery). It’s one of natures great aroma killers. Again, it’s the acidity that’s important, not the flavor. Citric acid has a lovely way of converting a volatile amine known as trimethylamine (the compound responsible for “fish smell”) into a non-volatile ammonium salt. The effect is of course to put the hammer down on fish odors, however subtle, that might effect the flavor of the flesh. The same effect can be achieved with just about any citrus — or acid for that matter, which is why vinaigrettes of various types are frequently paired with fish.