Hi Tia! I was looking at my sources for this post and in Onion: Nature Protection Against Physiological Threats by Suleria, Butt, Anjum, Saeed, and Khalid there’s graphic that shows propane s-oxide reacts with water and forms propionaldehyde, sulphuric acid, and H2S. Another good paper might be Corzo-Martinez, M., Corzo, N. and Villamiel, M. (2007). Biological properties of onions and garlic. Trends Food Sci. Technol. 18:609–625. I really hope one of these helps!