Cacti are generally considered to be hostile, unfriendly plants. Which, frankly, is understandable. They're covered with spines, they grow in hostile, arid climates. Even the adjectives used to describe them are unpleasant.
But cacti want to be our friends. Once you get past their thorny exteriors, you find a soft, fleshy, and usually delicious heart. The succulent agave plant gives us tequila, and nightblooming Hylocereus cacti bear pitayas (which we know as dragonfruit). Even the stereotypical cactus of the cartoon world, the saguaro, produces an edible fruit. And then there's my personal favorite, the prickly pear.
Both the pads and the fruit of the prickly pear cactus are edible. The pads, called nopales or nopalitos, can be found canned in hispanic markets and in well-stocked grocery stores, or fresh at a good farmer's market. They're crunchy and slightly sticky (similar to okra), and taste fresh and green - like green beans, asparagus, and green pepper. They're great on pizza.
But we're here for the fruits.
The fruits can very in color and flavor depending on the cultivar of cactus they're harvested from. In my area (the southeastern US), I typically see red fruits, which have a delicate melon-like flavor with a texture similar to that of a kiwi. If I was to describe the flavor more quantitatively, I could cite studies
which show the main odor-active compounds are similar to those found in cucumbers and melons. Unlike many fruits, they have a fairly low pH, meaning that you get the sweet without too much of the tart.
"So," I can hear you thinking, "what is it about these fruits that would justify me poking around a cactus?" I'm glad you asked!
Prickly pear fruits are rich in vitamin C, and colored by betacyanins, both of which are powerful antioxidants. They are a good source of fiber, and are high in calcium and magnesium.
Also, they're delicious.