SitNews - Stories in the News - Ketchikan, Alaska

Chemical Eye on a Sweet Thang
by Preston MacDougall


March 25, 2006

"How sweet it is?"

No, that's not a mispunctuated Jackie Gleason catchphrase. It is a question that one might hear from a flavor chemist with street cred.

For instance, the sweetness index of aspartame is cited as 160. This means that, compared to an equally concentrated mixture of sucrose (the chemical name of plain sugar) and water, the aspartame solution will taste 160 times as sweet.

jpg Preston MacDougall

A much younger Preston MacDougall.

This is presumably the average result of many taste tests, where the taster's choice is between a standard sugar solution and a greatly diluted aspartame concoction. And instead of your optometrist repeatedly asking "better or worse?", the flavor chemist would ask "sweeter or not?". Knowing how my own tastes have changed over the years, I imagine that there is quite a range in these results. Recently, there have been great advances in the molecular understanding of taste, but there is still no accounting for it.

Aspartame is made by linking two naturally occurring amino acids - phenylalanine and aspartic acid - just as is done when your body assembles the proteins we need to live and grow. All such polypeptides have a free acid at one end, and a free amine at the other. In aspartame, the free acid end is reacted with methanol, also known as wood alcohol, resulting in what is called a methyl ester group. Such a grouping of atoms is naturally found in many fruity flavors, such as pineapple (methyl butanoate) and orange (methyl anthranilate).

Digestion of the tiny amounts of aspartame that are in diet soft drinks produces harmless amounts of methanol, but it also reproduces the phenylalanine it was made from. This can cause health problems for people who have the genetic disorder called phenylketonuria, or PKU. Inherited in a recessive fashion, affected people lack the enzyme needed to break this amino acid down to yet smaller molecules.

If chemists focus their tinkering on the other end of the sweetened dipeptide, the amino end, they can really turn on the charm. By swapping out one of the hydrogen atoms that is bonded to the nitrogen atom at this end, with a bulky six-carbon chain that is "saturated" with hydrogen, one obtains neotame, and scores over 10,000 on the sweetness index!

Designing molecules is not that different from composing music or writing lyrics. For instance, swapping out the "i" in "sweet thing" for an "a", turns a tasty treat into a smash hit by Ernest Tubb and Loretta Lynn.

Appropriately enough, when I think of "sweet music" I think of Pérez Prado's Afro-Cuban jazz number "Patricia". This mambo hit was made world famous in 1961 by its recurrence during the classic Federico Fellini movie "La Dolce Vita". It seemed to be reminding the lead character, a tabloid journalist who was searching for fulfillment in his playboy lifestyle, that the sweetness of life was everywhere.

I first succumbed to the charms of this song long before I was old enough to watch, let alone enjoy, a Fellini movie. If you roller-skated during the '60s, you couldn't avoid this song. I am sure that to some, the bouncy organ beat and brassy shouts sound saccharin. What can I say, there's no accounting for taste.

Around the same time that I was honing my moves on the roller-rink (which I told my friends was off-season training for hockey) my sense of fashion responded well to blue velvet - with fringes! - and loud paisley patterns.

I haven't yet read about any research results suggesting that there is a genetic basis for tastes in fashion. But if there is one, I suspect that my maternal grandfather, Stanislaus Mazur, who was Polish through and through, and the sweetest man that I have ever met, lives on not just in my heart and mind, but also in my closet.

In "La DolceVita", all sorts of random occurrences redirect the searching by the character played by Marcello Mastroianni. And while I may be the farthest thing from a playboy, I think Fellini's point is that we are all starring in our own emotional epics.

It is interesting to look back on random events, both those that did and those that didn't happen. What if instead of the chemistry set that I begged for, my parents had given me the accordion that my fashion statements were screaming for?

Perhaps you might be listening to me, while reading someone else's commentary. And you wouldn't be scratching your head; you would be tapping your toes.

Na zdarovia!



Preston MacDougall is a chemistry professor at Middle Tennessee State University. His "Chemical Eye" commentaries are featured in the Arts and Public Affairs portion of the Nashville/Murfreesboro NPR station WMOT (

Publish A Letter on SitNews
        Read Letters/Opinions
Submit A Letter to the Editor

Stories In The News
Ketchikan, Alaska