Banana peel

A banana peel, also called banana skin in British English, is the outer covering of the banana fruit. Banana peels are used as food for animals, in water purification, for manufacturing of several biochemical products as well as for jokes and comical situations. There are several methods to remove a peel from a banana. Bananas are a popular fruit consumed worldwide with a yearly production of over 165 million tonnes in 2011. Once the peel is removed, the fruit can be eaten raw or cooked and the peel is generally discarded. Because of this removal of the banana peel, a significant amount of organic waste is generated. Banana peels are sometimes used as feedstock for cattle, goats, pigs, monkeys, poultry, fish, zebras and several other species, typically on small farms in regions where bananas are grown. There are some concerns over the impact of tannins contained in the peels on animals that consume them. The nutritional value of banana peel depends on the stage of maturity and the cultivar; for example plantain peels contain less fibre than dessert banana peels, and lignin content increases with ripening (from 7 to 15% dry matter). On average, banana peels contain 6-9% dry matter of protein and 20-30% fibre (measured as NDF). Green plantain peels contain 40% starch that is transformed into sugars after ripening. Green banana peels contain much less starch (about 15%) when green than plantain peels, while ripe banana peels contain up to 30% free sugars. Banana peels are also used for water purification, to produce ethanol, cellulase, laccase, as fertilizer and in composting. Banana peel is also part of the classic physical comedy slapstick visual gag, the 'slipping on a banana peel'. This gag was already seen as classic in 1920s America. It can be traced to the late 19th century, when banana peel waste was considered a public hazard in a number of American towns. Although banana peel-slipping jokes date to at least 1854, they became much more popular, beginning in the late-1860s, when the large-scale importation of bananas made them more readily available. Before banana peel jokes came into vogue, orange peels, and sometimes peach skins, or fruit peels/peelings/or skins, generally, were funny, as well as dangerous. Slipping on a banana peel was at one point a real concern with municipal ordinances governing the disposal of the peel. The coefficient of friction of banana peel on a linoleum surface was measured at just 0.07, about half that of lubricated metal on metal. Researchers attribute this to the crushing of the natural polysaccharide follicular gel, releasing a homogenous sol. This unsurprising finding was awarded the 2014 Ig Nobel Prize for physics.