Chapter 2: Understanding the Tear-Inducing Chemical

Syn-propanethial-S-oxide is a defense mechanism employed by onions. This makes sense, considering that they grow underground and must protect themselves from critters like voles. When an onion’s cells are damaged, sulfur-rich amino acids react with water to form propenyl sulfenic acid, a process catalyzed by the enzyme alliinase. Subsequently, another enzyme, lachrymatory-factor synthase, converts this compound into syn-propanethial-S-oxide. This compound is highly volatile and, upon contact with our tear-filled eyes, creates sulfuric acid, triggering reflex tears. This can be quite bothersome, especially when preparing meals for a crowd, such as French onion soup.

The first video, Why do onions make you cry? The science behind botanical warfare, delves into the fascinating science behind why onions provoke tears and the underlying chemical processes involved.

While onion juice has its downsides, propanethial-S-oxide also boasts antimicrobial properties. Historically, it was even used as a treatment for wounds during the American Civil War. Sensitivity to this compound varies among individuals; some may find themselves less affected, making them ideal candidates for onion chopping tasks.

Section 2.1: Alternatives and Innovations

Onions from the allium family exhibit varying levels of enzymes that produce propanethial-S-oxide. For instance, spring onions are a milder option compared to their larger counterparts. Interestingly, a New Zealand research team has developed genetically modified “no-tear” onions with significantly reduced lachrymatory synthase, resulting in lower levels of this tear-inducing chemical.

Curiously, the flavor of onions may be influenced by environmental pollutants. Sulfur emissions can result in acid rain that, when absorbed by soil, increases sulfur content in growing onions, impacting their flavor. As we strive for cleaner air, we might notice changes in onion taste.

Section 2.2: Tips for Tear-Free Chopping

If you want to minimize tears while chopping onions, consider wearing specialized "onion goggles" or chilling the onions in the fridge or freezer to slow down the production of syn-propanethial-S-oxide. Since this compound is released when onion cells are crushed, using a sharp knife to make clean cuts can help reduce cell damage. Additionally, the root of the onion contains a high concentration of sulfur compounds, so try to avoid cutting into that area when possible.

The second video, How To Stop Onions From Making You Cry, provides practical tips and tricks for reducing tears while chopping onions, making your cooking experience more enjoyable.

So, remember to ventilate your kitchen, grab your sharpest knife, and confidently tackle that onion. With these strategies, you can savor their flavor without the tears!

Happy chopping!