I'm going to completely ignore the dnd-5e tag, because this is a fluff question, not a crunch one. The diet of the minotaur won't affect a bit of his game statistics.
While the question is about the Dragonlance brand of minotaur, let's indulge. The original analysis of the Greek minotaur monster is below.
The Krynn minotaurs are a different kind of minotaur than the original:
Most of Krynn’s minotaurs are informally known as Blood Sea minotaurs, named for the treacherous ocean area in which they are commonly encountered.
The habitat of those minotaurs is the sea, so their diet will favor sea-food. Onwards to their ecology:
Minotaurs produce a variety of products, among the them smoked and canned fish, (...) Minotaurs eat a variety of food but they have a special taste for fish, mutton, and raw rains. They also enjoy strong ales and beers.
The shared rations is probably smoked fish, since it can stay edible for longer. Canned fish would stay unspoiled for longer, and probably held as emergency rations (we called those Iron rations back in the old days).
For the "common minotaur monster", let us dig back into the AD&D 2e monster manual, and see the minotaur Ecology entry (page 252):
Minotaurs breed with human females to produce offspring, which are male minotaurs.
(...) They can live without food for years at a time, but are always hungry unless they are fed regularly. They are meat-eaters, but their curse causes them to prefer a diet of human flesh. (...)
I'll skip past the "live without food" part, because characters should starve. But since minotaurs are human offspring, they can be considered omnivorous like humans, with a strong preference for flesh.
Of course civilized minotaurs won't eat human flesh... very often or in public