/oss/taxonomy/term/5447/all en /oss/article/nutrition-you-asked/why-does-lettuce-turn-brown <p>That’s an interesting question. How lettuce turns brown is well known. But why this happens is a different story. Let's deal with the how first. The chemistry that takes place when lettuce leaves become brown is the same chemistry we see when an apple is cut and turns brown, when green guacamole turns brown or when a green olive ripens and turns black. All these reactions occur when chemicals in the fruit or vegetable called polyphenols react with enzymes called polyphenoloxidases. Enzymes are specialized protein molecules made within cells and serve as catalysts.</p> Fri, 04 Jun 2021 20:24:53 +0000 Joe Schwarcz PhD 8755 at /oss