Kitchen Chemistry 101: Taste, Cooking, and Microwaves

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‘Food chemistry is still in its infancy,” says Herve This in his book, Kitchen Mysteries, “We are very ignorant about the chemistry of cooking.”

I just finished reading two books on culinary chemistry of the kitchen, the second one being Culinary Reactions by Simon Quellen Field.  Of the two, Kitchen Mysteries is the more erudite, graceful, and exhuberant.  The literary quality of the writing is very good– a personal voice really shines through all the science talk.  Kudos also to the translator, for the book was written originally in French.  The book also contains more personal experiences and advice than Field’s book, including some personal advice such as this gem:

“Like Brillat-Savarain, I am well aware that to speak without pretension and to listen with kindness… that is all that is necessary for time to flow sweetly and swiftly.”

Field’s Culinary Reactions suffers in comparison, not least because of its redundancies… as if the book were written in a hurry or patched together and no one checked to see if some of the same basic sentences had not already been stated in another section of the book.  On the other hand, the science in the Culinary Reactions is explained just as well as, if not better than, the science of This’s book.

Mr This believes that anyone with a love of food (a “gourmand” he points out is the proper term; a gourmet being, technically, a lover of wine, not food) can become a connoisseur.  Experiments have shown that “we can train ourselves to develop fine palates.”

This believes that the schoolbooks are dead wrong when it comes to teaching about taste.  The standard texts teach that tastes can be divided into four groups (sweet, sour, salty, and savory), maybe five in some books– but This contends that “tastes are astonishingly complex” and that to properly describe the human sense of taste we would require at least ten different categories.

We learn that two things are required for something to have taste:  1) water-soluble molecules in the food and  2) the molecules can activate our tongue’s taste receptors.

Some of our tastes, despite the general complexity of the sense, are actually quite simple.  What we experience as a salty taste comes only from sodium ions in food, and our sour tastes are due to the presence of hydrogen ions. Glutamates, an indicator of foods rich in protein, can give us that savory sensation that some foods, like meat, contain.

Smell is also an important component of a good meal.  However, substances with non-volatile molecules can be quite odorless– if no molecules are bouncing around and getting picked-up by our nostrils, than no taste will be perceived.

Much of cooking involves the denaturing of proteins by a variety of methods, including stirring, beating, whipping, cooking, and even the application of acidic compounds such as lemon juice or marinades, since acids, like heat, can cause proteins to denature.

When proteins denature, cell membranes in the food can burst, unleashing a torrent of changes– all to the good if everything goes according to plan.

Although it is, indeed, true that cooking can destroy some of the nutrients in food, cooking can also make available MORE nutrients in our diet by softening foods and allowing us to consume foods we normally would have a difficult time eating.  Heating foods can soften starches and gelify tough connective tissues.

Most Americans today, besides ovens and stove-tops, also use microwaves to cook foods.  You might think Chef This would turn his nose up at microwave cooking, but on the contrary, he feels the microwave has its place in the kitchen, as long as it is used in the right situations in the right way.

The microwave works, he explains, by emitting electromagnetic energy from a device it contains called a magnetron.  These electromagnetic waves are emitted at a low frequency, a frequency below both the visible spectrum and infrared radiation, but above that of television and radio frequencies.  The waves interact with the most abundant electrically asymmetrical molecule in most foods– H2O– causing the water molecules to begin moving faster and thus, to begin heating.  This movement/heat is transferred to the rest of the food, thereby cooking the entire substance.

Because water is the heat carrier for microwave cooking, “nuked” foods cook no hotter than foods that are boiled– that is, microwaved food typically gets no hotter than the boiling point of water, or 212 degrees Fahrenheit.  Thus, microwaves are not very good for browning foods.

More kitchen chemistry posts to come!

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