Why lettuce turns brown

One more item about preparing lettuce: the dressing should always go on at the last moment because oil soaks into the leaves readily and makes them soggy. And noting that lettuce is soggy is not culinary snobbery. What about the why? The main theory that crops up is that the brown pigment has anti-fungal and insecticidal properties.

In other words, the damaged fruit or vegetable is trying to protect itself. The argument is that historically damage was caused by insects and fungi and that at the first sign of such damage the enzymes would swing into action to ward off further destruction. The problem is that nobody has clearly demonstrated that the brown pigments really do have antifungal or insecticidal properties.

But there certainly is some interesting chemistry there. Enter your keywords. If you rupture the cell walls of lettuce leaves, which can happen if you cut or bruise the leaves, they come in contact with the air.

This causes a chemical reaction that turns the leaves brown. Homegrown lettuce can also turn brown on the tips out in the garden when exposed to harsh weather conditions or improper soil.

The ripening chemical known as ethylene, which many fruits including bananas produce naturally, can also hasten browning of lettuce leaves. Start with a quality head of lettuce -- avoid any that look wilted or limp. Excessive moisture is the enemy of lettuce -- but the right level of humidity leads to crisp leaves. Keep whole heads of lettuce intact. Wrap them in a lightly dampened paper towel , and then in a plastic bag or sealed storage container. Small leaves should be washed immediately and thoroughly dried.

Then place them along with several paper towels in a sealable plastic bag or box. This is because these fruits give off high levels of the gas ethylene which speeds up the ripening process. Cold temperatures in an extra chilly fridge might also result in browning lettuce because the cold breaks down the cell walls in the lettuce leaves, which can lead to rot.

Keeping your lettuce in the crisper drawer, as opposed to the bottom shelf in the back of the fridge where it's the coldest, will help prevent this. As for eating lettuce with some brown areas, well, here's the good news.

You can confidently tell your children that they still have to choke down that brown lettuce because it's perfectly safe to eat via Berkeley Wellness. However, it may have lost some of its nutritional value and probably won't taste quite as fresh as the day you bought it, so feel free to trim those brown parts before adding it to your salad.