At the South American grocery store/restaurant on Devon (probably about 1300-1400, south side of street)-- why can't I recall the name-- famous on LTH for the Cuban sandwiches-- La Unica! -- wonderful frozen fruit juices/concentrates in the freezer. I made excellent passionfruit (maracuya) sorbet as well as other flavors-- mora (blackberry) and I think guanabana (never heard a translation for this). Inexpensive and very tasty.
I have seen passion fruit at Whole Foods (Peterson?). But it was so small and dried up looking and very expensive, so I never bought it. I made passionfruit juice once in Ecuador, at the direction of the lady of the household where my son was living. Maracuya juice was my favorite, I had been drinking it in cafes all week, so I was very excited to make it myself. She whacked two maracuyas the size of large grapefruits off at the top, and gave me a large spoon to scoup out the insides. I doubled over with laughter because the inside looked a lot like fish eggs, and not the kind I would want to eat, either. Very gross!! Luckily I knew I loved the stuff, so I scouped it into a blender. She put in quite a bit of sugar (if I were doing it at home I'd use a bit less) and water, and turned the blender on. After a minute or so, I poured the mix through a sieve, and presto, excellent maracuya juice.
Just thinking about it makes me want to go back to Ecuador. The last day there, we bought some of every fruit we didn't recognize at the grocery, and took them home to the lady of the house, who told us what they were and how to eat them. My favorite was uvillas, which looked more or less like large orange cherry tomatoes, but had a fruit taste that was fabulous. Because they were eaten skin and all, according to my guidebook, I should not have eaten them, but I threw caution to the winds and ate quite a few, with no bad effects. According to internet research after I got back, they don't travel well and are not sold outside Ecuador. Very sad.
One last comment on the sorbet-- I made quite a bit last summer-- the frozen juice always seemed better than anything I found in a carton or bottle.