Jim Topitzhofer, age 10, of St. Paul, Minnesota, for his question:
Does banana oil come from bananas?
Dogs, of course, are not members of the flowering dogwood family and cats, perish the thought, have nothing to do with the reedy cattail. It grows in the marshes and cats cannot abide the water. These farfetched relationships crept into our language because one thing often reminds us of something else. So it is with banana oil.
Banana flour is made by powdering green, unripe bananas. It has, they say, twice as much nourishment as wheat flour. We do not have to report on the delicious flavor of ripe bananas because everybody knows about it. Those golden fingers also happen to be stuffed with valuable food, plus generous doses of vitamins A, B and C. In the hot, moist tropics where banana trees grow, their tough stalks and stems may be used to make roofs and rugs. But nobody has found a way to get banana oil from banana trees or from bananas, ripe or unripe.
The fact of the matter is that banana oil was named for its smell. It is a man made chemical with a very strong, fruity odor somewhat like the smell of bananas. Maybe you have smelled it if you happen to be around when a female in your family is giving herself a manicure. Banana oil is used in the mixtures of polish and polish remover inside those little bottles. It is a colorless liquid chemical named amyl acetate.
The various acetates form a large and very useful family of chemicals. They are compounds of acetic acid, the stuff that gives that sour taste to vinegar. The word acetate is coined from the Latin word for vinegar. Table vinegar is from 3 per cent to 6 per cent acetic acid, but pure acetic acid is caustic enough to burn. It also freezes solid at 62 degrees, the temperature of a fairly cool room.
Acids are famous for reacting eagerly with other chemicals.: Acetic acid reacts with metals, oxides and hydroxides to form the chemical salts called acetates. When acetic acid . reacts with alcohols, it forms acetate salts called esters. Amyl acetate, alias banana oil, is a salt of amyl alcohol and acetic acid. This strong chemical can dissolve woody cellulose and large amounts of it are used in textile mills to make rayon. It also is used to make celluloid and other more modern plastics.
Sometimes you get a whiff of amyl acetate in the silvery paint they use to coat radiators. It may be in certain glossy paints and lacquers. And:.let's not forget that smells are related to tastes. Banana oil is blended with other fruity smelling chemicals to make various artificial food flavorings and extracts. In these blends, naturally, the strong smelling chemical is diluted down to a mere whiff.
A wide variety of ester acetates are manufactured by plants, but for use in industry it is cheaper to make our own. It is esters that give those delicious flavors to fruits. Each fruit, of course, has a flavor all its own. As a role, it comes from one outstanding ester and a blend of several others. The tangy taste of a pineapple comes mainly from an acetate ester called ethyl butrate. Fruits have only tiny traces of these chemicals, certainly not enough for us to extract from them the tons of chemical esters we use in industry.