I 
have a soft spot for carbohydrates. 
That’s because they helped launch my 
scientific career. My PhD research 
explored the subtleties in the molecular 
structure of simple carbohydrates using 
nuclear magnetic resonance spectroscopy 
(NMR). As I dipped my toe into the car­
bohydrate pond, it quickly became obvious 
that this was no mere pond, it was an ocean!
The term “carbohydrate” was origi­
nally assigned to substances based on their 
elemental composition. They all seemed to 
conform to the formula Cm(H2O)n, sug­
gesting that they were “hydrates of carbon,” 
with “hydrate” referring to any substance 
that contains water. Besides being the 
body’s main source of energy, “carbs” impact 
our lives in numerous ways. Cotton fibres 
are made of cellulose, a carbohydrate com­
posed of glucose molecules linked together 
in long chains. 
Starch, just like cellulose, is a poly­
mer of glucose, but the glucose units are 
linked together in a slightly different fash­
ion, giving it different properties. It can be 
used to thicken a stew or bind pulp fibres 
together in paper. The simple carbohydrate 
sucrose makes coffee taste sweet, but over­
consumption can have a bitter effect on 
health. High-fructose corn syrup in pro­
cessed foods is maligned as contributor to 
obesity, while beta-glucan, a carbohydrate 
found in oats helps reduce blood cholesterol.
Given all this, it should come as no 
surprise that my digging into the carbo­
hydrate literature resulted in an enduring 
fascination with these compounds. That 
came in handy when upon graduation I 
was lucky enough to enter academia and 
start teaching, which is what I had always 
wanted to do. I was assigned a course called 
“Chemistry in the Modern World” that was 
designed for non-science students. The syl­
labus was vague and basically, I could do 
whatever I wanted.
I had done some teaching in graduate 
school and became convinced that the way 
to get students interested in chemistry was 
by pointing out the role it plays in daily life. 
I was especially intrigued when the profs 
mentioned some tidbit about paints, bat­
teries, sea snails that exude a purple dye, 
chemicals that insects use to attract each 
other, or nylon being used to make tooth­
brush bristles. 
SENSE, NONSENSE AND SCIENCE
BY: JOE SCHWARCZ
FOR THE LOVE OF CARBS
When I got the chance to teach, I 
decided that my emphasis would be on 
such gems. I hoped that if the everyday 
applications of chemistry were appreciated, 
students would be motivated to learn about 
the chemical reactions that bring them 
about. I thought drawing examples from 
this domain would be my best chance to 
kindle interest. I decided to start the class 
with what is often considered to be the 
oldest known chemical reaction. That is 
fermentation, the conversion of sugar into 
alcohol with the aid of yeast. I remember 
eliciting some chuckles with the line, “man’s 
desire to be drunk is older than his desire 
to be clean”.
Fermentation readily segued into an 
explanation of why sugar is a carbohydrate, 
and that in chemistry the term “sugar” is 
used to describe a number of simple car­
bohydrates that have a sweet taste. The 
sweetness in grape juice comes from a 
mixture of glucose, fructose and sucrose, 
the latter being composed of a molecule of 
glucose joined to one of fructose. Glucose 
molecules can join together to make either 
starch or cellulose, and that while we can 
eat the former, we don’t have the enzymes 
to digest the latter. But cows do, so they can 
dine on grass.
I finished the lecture with the story 
of nitrocellulose, explaining that it is a 
highly flammable substance and was given 
the name “guncotton” because at one time 
it was rammed into a cannon and ignited 
to produce the expanding hot gases needed 
to propel a cannon ball out of the barrel. I 
lit a sample of guncotton and was pleased 
to see the students gawk in amazement as 
it instantly disappeared in an orange flame 
without producing any smoke! 
I followed with a historical account 
of how French industrialist Hilaire de 
Chardonnet discovered that when a solution 
of guncotton is extruded through a show­
erhead-like device, the solvent evaporates, 
leaving behind a thread resembling silk. 
This was then woven into the world’s first 
synthetic fabric that looked like silk and felt 
like silk. It was highly flammable! 
The story of carbohydrates has 
expanded as well. Now we talk about using 
genetic engineering to help crops produce 
starch that resists digestion and feeds the 
microbes in our colon that then crank out 
chemicals with a host of health benefits.
Looking back, carbohydrates were not 
only instrumental in forging my career, they 
have also helped in igniting an interest in 
chemistry in generations of students. And 
yes, I still do the guncotton demo and they 
are still amazed. 
Editor’s Note: This is an abbreviated version. 
For the full column, see https://www.seed­
world.com/europe/2026/03/25/for-the-love-
of-carbs/  
Joe Schwarcz PhD is Director, McGill 
University Office for Science and Society, 
Montreal, QC, Canada.
MAY 2026  |  SEEDWORLD.COM/EUROPE  I  SEED WORLD EUROPE   I   21

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