The general recipe calls for cutting bananas of the appropriate ripeness into small pieces, freezing them, then mashing them (e.g., in a food processor or blender). When the mash warms up a little, the 'grains' coalesce, producing the 'ice cream.' How does it work? The 'one-ingredient' recipe linked above mentions that bananas work well because they are high in pectin. But many other fruits are also high in pectin--would it work just as easily with them? This article explains that it's a little more nuanced than that--it's not just pectin, but pectin, fiber, and sugar that work together to give the creamy texture. (From a physical chemistry perspective, the smaller the ice crystals in the product, the creamier it will feel. The sugar and polysaccharides decrease water's ability to form and grow ice crystals by messing with water's hydrogen-bonding network.)
So, fruits that are high in pectin, fiber, and simple sugars should be able to make a nice creamy sorbet/ice cream (sorbeam?), too. Time to compare some data!
|Fruits with a lot of sugars, fiber, and pectin give a creamier texture in one-ingredient 'sorbeams.' Data sources are here, here, and the paper linked here. A qualitative list of pectin levels in fruit can be found here (and many other places online). Bananas are unique in their high content of available sugars, nearly twice as high as the other kinds of fruit for which we could find numbers. So, in theory, it should work a lot better with bananas than almost any other fruit. But hey, we're experimentalists! Why don't we try it with our apples and plums anyway, and see if we like it! (After all, if if it's not all that good, Jake will eat it anyway.)|
|At first, the frozen fruit (apples, here) makes sort of isolated granules.|
|As it starts to warm up, the granules start to stick together, but it stays kind of icy. It's vaguely reminiscent frozen applesauce--not bad, but not what we're shooting for.|
|But add bananas, and bam! Creamy ice-cream-like texture.|
|Same thing for the plum as for the apple. (If you leave the peels on, they stay in the sorbeam as fun confetti sprinkles!)|
|You can scoop it into bowls and top it with dried apple slices and cinnamon, or whatever normal people put on ice cream.|
The amount of banana flavor depends on the ripeness of the bananas. (The creaminess of the texture, to some extent, too.) While visiting family in July, we were introduced to a new term for bananas with brown spots: giraffey (adj.: having the appearance of giraffe). We've expanded the concept to develop an entire animal-themed scale of banana ripeness. Further to the right gives more banana-ey flavor; too far to the left makes the sorbeam taste starchy and astringent. We like somewhere between giraffe and black bear; those less fond of banana flavor could edge toward puffer fish, but definitely don't go all the way to hummingbird. Photo credits for hummingbird, puffer fish, giraffe, black bear: Wikipedia. Other sources for the green, yellow, spotty, and black bananas.
How do you prepare frozen fruit desserts? Let us know in the comments section below!