Roses are Red, Violets are Blue…

…and what is it that makes sugar sweet, exactly? Or maybe more specifically, what is it that makes some sugars sweeter than others?

Sugars are part of a broad family of molecules known as carbohydrates. They are in fact the simplest carbohydrates, and just like other conspicuous members of their family, they are critical sources of energy for both plants and animals. Among the most common are so-called monosaccharides which I ranted about yesterday (excuse me for that, I was feeling a little feisty…must have been something I ate). Like their name implies, monosaccharides are are single-sugar carbohydrates. Glucose and fructose are two examples. Being such simple structures, they are readily absorbed by the body to fuel the workings of cells (fructose actually has to be converted to glucose before it can be used).

Because monosaccharides are so critical to us, our bodies are equipped with special sensory equipment that allows us to detect them: taste buds. When taste buds encounter a monosaccharide like glucose they send a signal to our brain that says “Energy! Energy! Energy!”, which is interpreted by us as the pleasurable sensation of sweetness.

But then monosaccharides aren’t the only carbohydrates that taste sweet to us. Some two-sugar carbohydrates, or disaccharides, create a similar sensation. Notably sucrose (table sugar), maltose, and to some extent, lactose.

What happens when you add more sugar molecules to the carbohydrate chain? You get so-called oligosaccharides (“oligo” being latin for “few”). These are three- four- and five-sugar carbohydrates that are commonly found in vegetables. Our bodies can digest many, but by no means all, of these types of carbohydrates, so it’s hardly surprising that our tongues don’t have the same reaction to them.

Add still more sugars and you have polysaccharides, chain-like carbohydrate molecules that can be anything up to thousands of sugars long. Even though some of these types of carbohydrates, the ones we call starches, can be digested and broken down to usable glucose, their complexity makes them virtually undetectable to our taste buds, which is why a starch like plain flour tastes like almost nothing at all.

But then the size of the molecule isn’t the only thing that affects a carbohydrate’s sweetness. Even simple little monosaccharides are different from one another chemically, and that impacts how they’re received on the tongue. Fructose, for example, is detected on contact, while glucose takes a bit more time to create the sensation of sweetness (disaccharides also differ from one another in this way). Exactly why the tongue interprets sugars differently is a topic of near endless speculation for food scientists (and to some extent, anthropologists). By the same token, the variety of sensations different sugars create are an endless source of experimentation for candy makers, who manipulate them to produce various effects.

I’m not sure I even answered my own question. But Lordy, look at the time…

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