Salty posted a video before about a knife TK59 sharpened for him.
TK sent me a Devin Thomas PM San Mai gyuto to try out. After an hour or so of cutting stuff at work, I diced some apples. I did not put them in water or put any lemon juice on them. At the end of my shift, they were still white and pristine. I put them in a quart container and saved them for the next day. Here they are more than 24 hours later:
They actually look more oxidized than they were. These are in a ninth pan with my crummy Blackberry camera, so the colors aren't super accurate.
TK says it's my technique, I say it's his edge, perhaps it is both.