Did you know letting onions rest after chopping can make them even better for you? Here’s the scoop: slicing or chopping onions kicks off a biochemical reaction. The enzyme alliinase gets to work, transforming sulfur-containing compounds into thiosulfinates—like the famous allicin found in garlic, but with onion’s own unique twist. These thiosulfinates are thought to support immune function and may help your body fight oxidative stress (Randle, 2021; Food Chem).
But here’s the catch: if you immediately toss onions into a hot pan, you cut short the enzyme’s work. Giving chopped onions about 10 minutes on the cutting board lets those beneficial compounds fully form. Studies show that this short pause increases levels of quercetin and thiosulfinates, maximizing the bioavailability of these phytochemicals in your meal (Nuutila et al., J Agric Food Chem, 2003).
So next time you’re prepping a stir-fry or soup, chop your onions first and let them hang out while you get the rest of your ingredients ready. Your tastebuds—and your body—will thank you!
