When cooking, what's worse - high temperatures over a short time, or lower temperatures for a longer time?
Example 1 - Salmon
Everyone's always telling me to steam, poach or bake salmon so as to not oxidize the Omega-3's. In my opinion the best way to ruin fish is to throw it in the oven; I much prefer a sear in a smoking hot cast-iron pan. However, I like my salmon very rare - seared on the outside, sushi on the inside. Have you ever had rare steamed salmon? I haven't - whenever I bake, steam or poach salmon it ends up getting cooked all the way through, which I'd think would oxidize more fats. So what's better for PUFA preservation - a rare sear, or steaming all the way through?
Example 2 - Broccoli
I've heard that Vitamin C is very sensitive to heat, and is rapidly denatured by cooking. However, here's some data on broccoli from NutritionData: Broccoli, Raw - 27mg Vit C. Broccoli, Boiled (who the hell boils broccoli?) - 24mg Vit. C. I used "5-Inch Spear" as the quantity to avoid change in weight through cooking. So that's only a 12% decrease in Vitamin C levels. Is that because Vitamin C is more hardy than we thought, or does it just take higher temps to denature? Again, I like to saute broccoli at high temp but for a short time, leaving it crunchy on the inside. So what's better for C preservation, a crunchy saute or steaming all the way through?