Cooking For Engineers

[CookNewb]

Hello all! I was wondering if anyone knows why if you cut salad leaves with a metallic knife they oxidize faster than when cut with a plastic or ceramic knives.

[kgb1001001]

According to Alton Brown, the reason why you want to tear lettuce (and herb) leaves rather than cut them is that if you use a sharp knife you are breaking more cell walls open and exposing the damaged cells to oxygen. If you tear something then it will tend to naturally separate along the cell wall boundaries.

Never heard of using a plastic or ceramic knife to do this, but I'd bet a plastic knife wouldn't be very sharp and would probably be just like tearing...

[watt]

salad leaves sold in supermarkets are all cut using plastic knives. It is said that the iron in a steel knife reacts with the contents of the cells in the leaves. The browning is said to be reduced if left in water. This may be because of reduced oxygen, perhaps used in enzymatic reactions which turn the leaves brown.

just thoughts
watt