Citrus had not yet made its way to Greece during the Greek Bronze Age. No lemons and limes for cooking, no oranges, no grapefruits on the table, much to my dismay. Sweet Oranges took their (sweet) time making an appearance in general, really, and in northern Europe they suffered from a lack of availability and cultivation as late as the 15th century AD. But though these fruits weren't yet being cultivated in the west during the bronze age, they were absolutely being cultivated elsewhere.
In the Far East of Asia, there are mentions of citrus fruits as far back as 2400 BC in China (and this website by Mark Rieger originally put together for his horticulture class at UGA has everything you'd ever want to know about citrus today, if it's a bit sparse on the days of yore). And if there's one thing we know about the Greek Bronze Age, it's that they weren't shy about trade, nor were heroes like Theseus and Pirithous likely to be afraid of exploring new oceans, seas, or rivers.
In Homer's Odyssey, in fact, there's a reference to Odysseus wearing a material which is believed to be silk:
"And I noted the tunic about his body, all shining as is the sheen upon the skin of a dried onion, so soft it was; and it glistened like the sun" (19.233).This attestation to another commodity of the Far East which had not spread widely allows the savvy writer a little bit of leeway when it comes to bringing Homeric myths into the historical world. While it's clear these kinds of luxuries were absolutely not available to even the common king or queen, it isn't outside of the realm of possibility for a hero to have collected such spoils, or even to have gone out of his way to present them as incredibly valuable gifts for a special occasion.
And if there's one thing we know about the Heroes of Greek Myth, Homeric and otherwise, it's how much they loved raiding, rustling, and sacking everyone from their neighbors, to the richest cities and kings they could find.
Of course, we already knew that Bronze Age kings likely also fulfilled roles as priests, or religious leaders -- but we shouldn't forget that kings like Pirithous or Theseus? They were most definitely Pirates, too.