Mysteries in the kitchen

Remember when you were a child and bit into a chocolate-covered cherry? The sugar

syrup ran down your chin, and it tasted wonderful.

When this candy was made, each cherry was rolled in a thick paste of very fine sugar crystals to form a ball, which was then dipped in chocolate. What caused that thick sugar paste to turn into syrup while it was completely sealed in chocolate?

Here’s another mystery. Cassava, the source of tapioca, contains cyanide, yet it is a major food in many parts of the world. How can this be? Then there is the white chocolate banana cream pie mystery. When it is made, it is so thick you can stand a spoon up in it. The next day, it is soup. What happens?

These strange occurrences and thousands more are the work of mischievous proteins called enzymes, whose job it is to start or speed up chemical reactions. We can make these little fellows work for us if we understand their structure and function.

Enzymes have a jigsaw-puzzle configuration that fits exactly the substance they are going to break down. They latch onto the substance and pull or strain the bonds in the area where the substance is going to break. Once the substance is almost apart, the enzyme spits it out. The substance then breaks apart on its own, and the enzyme moves on to another molecule.

All of this happens quickly. A single enzyme can break apart 1,000 molecules per second.

Back there in our white chocolate banana cream pie, if the filling did not get heated enough (up to 170 degrees) to kill the egg-yolk enzyme alpha amylase, a few surviving enzymes could gobble up the firm starch gel and easily turn it to soup.

With cassava, the enzyme that breaks up the cyanide and the cyanide itself are in the same cell but sealed off in separate parts. If the cassava is cut, this allows the enzyme to get to the cyanide and convert it to harmless compounds.

The traditional method of preparation is to chop or mash the cassava and allow it to stand for a while. This gives enzymes in the cassava plenty of time to render the cyanide harmless before it is eaten.

Most of us have cried while chopping onions. The onion enzyme and the substance that breaks up into the irritating gases are in the same cell. When we cut the onion, we allow the enzyme to get to this substance, and fumes are produced. This chemical warfare is an onion’s way of protecting itself when it is attacked. This is similar to what happens with cassava.

In making the chocolate-covered cherries, candy manufacturers add an enzyme from yeast to the thick paste, which is made of sucrose, a double sugar composed of glucose and fructose joined together.

When the enzyme breaks up sucrose into glucose and fructose, both of these sugars are more soluble than sucrose, and enough water is present for the sugars to dissolve into the thick syrup that can dribble off of your chin.

We witness enzymes in action every time we cut a piece of fruit and see the cut surface turn brown. This browning is desirable and an important step in flavor, aroma and color development of cacao, chocolate, tea and cider, although not in sliced fruits and vegetables.

Vitamin C prevents this browning, so to protect your fruit, you can simply crush a vitamin C tablet and dissolve it in a bowl of water. As you slice the fruit, toss it immediately into the vitamin C water. Or, because orange juice is high in vitamin C, place the sliced fruit in cold orange juice until ready to use. This is ideal for delicately flavored fruits such as bananas.

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