Cooking is part of chemistry, Chemical knowledge could help in some kitchen activities.
Preventing Fruit Browning:
When dealing with fruits like apples and avocados, it’s essential to understand the chemical processes at play. These fruits contain phenols, which, when exposed to oxygen, undergo a conversion to quinones. Cutting the fruit accelerates this process, leading to the polymerization of quinones into brown melanins.
To slow down this browning effect, the addition of acids, such as lemon or lime juice, proves effective. These acids inhibit the activity of polyphenol oxidase, the enzyme responsible for speeding up the quinone polymerization into melanins.
Chopping Onions Tear-Free:
The act of cutting onions releases allinase enzymes, breaking down amino acids sulfoxide. This breakdown produces 1-propenesulfenic acid, which is then transformed into propanethial S-oxide by the lachrymatory-factor synthase enzyme in the onion. It is this compound that causes the stinging sensation in your eyes.
To minimize the tearing effect while chopping onions, using a sharp knife is recommended as it causes less damage to the onion cells. Additionally, chilling the onions before chopping reduces the reaction rate and the volatility of propanethial S-oxide, providing a tear-free chopping experience.