Onions may seem like a humble kitchen staple, but how you prepare them can actually unlock more of their health-promoting compounds. Here’s the juicy detail: when you cut or crush onions, their cells release an enzyme called alliinase, which triggers the formation of allicin and other sulfur-containing compounds. These are the same compounds that make you tear up—and they’re also linked with potential antioxidant and immune-supportive effects in your body!
But there’s a catch: once you cut or chop an onion, giving it about 10 minutes to 'rest' at room temperature before tossing it into your pan or oven gives those enzymatic reactions time to fully develop. A 2016 review in Food Chemistry underscores this for allium veggies like onion and garlic—heat destroys alliinase, but if you give it that pre-cook downtime, you still get a big boost of those beneficial compounds.
So next time you’re prepping onions for a recipe, chop them up first and let them sit while you do the rest of your prep. This tiny tweak helps you squeeze even more benefits from an ingredient you probably already use all the time. You’ll get more of what makes onions special—without changing their flavor or texture.
