Tamarillos originate from New Zealand but are produced in the USA in California. Tamarillos are encased in a smooth, inedible skin and are the cousin of the eggplant (their mom and the eggplant's dad are brother and sister). Generally the fruit is eaten raw but can also be cooked. (For once, I did not use Wikipedia...this info comes from http://www.specialtyproduce.com/.)
The site mentioned above notes that these fruit taste like a cross between apricots and tomatoes...and if you think that sounds gross then you'd be right. This is quite possibly one of the most acidic fruits I've ever tasted--it is incredibly tart the acid level is off the charts. Sorry bout cha if you have acid reflux. At first the tartness and acidity is all you can taste but once that shock wears off you taste a hint of tomato as an aftertaste. It's not really pleasant and I don't think I'll be consuming this one on purpose again.
The tamarind tree is native to Africa and produces these tamarindo pods with edible pulp. The pulp flesh is generally described to be sweet and acidic in flavor and is a good source of B vitamins and calcium. (From Wikipedia...hello old friend)
The hull of the pod should be broken open, revealing a reddish-brown fleshy pulp inside.
(What would I do without Google images?)
There are inedible seeds inside the pulp. The pulp is a rubbery, sticky texture (much like a dried fruit...prunes, apricots, etc.). I was hesitant to taste it and for good reason...because when I did, my face turned inside out. This was the most sour piece of anything I've ever tasted. My jaws locked up, my eyes watered...it was bad. I had to spit it out. Even my hubby, who has a high tolerance for sourness (both in food and in my personality) had trouble. You know the face a baby makes the first time they suck on a lemon? Imagine that times 17 and you have our faces with this. I have no idea how this would or should be used. I can't imagine a possible reasonable culinary use for this product.