|Quoting JAGflyer (Reply 4):|
I heard that airline food has to be spiced/seasoned more than food that would be served on the ground as one's sense of taste is worse at altitude.
I'd heard this as well. There's research showing that people lose some of their sense of taste when they hear the white noise inside an aircraft's cabin. For that reason, airline meals tend to be saltier or sweeter than meals served on the ground. LH
even took their meals to a low pressure chamber to test the effects of cabin pressure on food taste. Basically, low humidity in the cabin effects the ability of the nose to smell the food, which is around 80% of what makes up what we taste.
Although it does not directly answer the OPs question some time ago in a different thread someone linked to a youtube video showing how airline meals were prepared. I believe it was this one.