Gel Carbohydrates in More Detail
Whether simple or complex, all carbohydrates in energy gels are sugars. The most basic form of carbohydrate is a simple sugar, which is categorized as either a monosaccharide (translation means ‘one sugar’) or a disaccharide (two sugars bonded together). Simple sugars are the building blocks of complex carbohydrates. Link three to ten together and you get an oligosaccharide (literally meaning ‘a few sugars’) while more than ten sugars joined together are called polysaccharides (or ‘many sugars’).
Glucose and fructose (Figure 2) are the two most common types of monosaccharides used in gels.
Although other disaccharides exist, gel manufacturers primarily use sucrose (Figure 3), which is made up of one glucose molecule and one fructose molecule linked together.
As stated above, a complex carbohydrate is technically any carbohydrate with three or more simple sugars bonded together. The overwhelming type of complex carbohydrate used in energy gels is maltodextrin (Figure 4 ).
Made from starch, maltodextrins are a mixture of varying length glucose chains (oligo- and polysaccharides). Almost all US sport nutrition companies use corn as the maltodextrin base (versus wheat or rice).
Maltodextrin is produced by heating starch and then adding acid and/or enzymes to break it into smaller pieces. These smaller pieces, or chains, can be anywhere from 3-19 glucose units in length. Very weak hydrogen bonds connect the glucose molecules together, consequently making them easy to digest in the stomach. So although maltodextrins are complex carbohydrates by definition (leading one to assume they might be more slowly burned/oxidized), the weakly bonded chains are broken down and absorbed in the intestine as quickly as glucose (about 1g/min).
Maltodextrins are classified by their dextrose equivalent, or DE, and range in value from 3 to 20 (not to be confused with their chain length values of 3-19). For simplicity’s sake, because maltodextrins are comprised of dextrose, the DE of a maltodextrin can be thought of as a sweetness measure, with dextrose having a standard value of 100. Variations in maltodextrin chain length determine their DE…. i.e., the shorter the chain, the higher the DE. Most maltodextrins used in energy gels have a DE value of 19 or 20, which corresponds to a fairly neutral taste (about 19-20% as sweet as dextrose).
The low DE of maltodextrin makes it a very attractive ingredient for use in energy gels because it provides a high concentration of carbohydrates (energy) with very little sweetness. Need a real example? Try this simple taste test at home comparing the sweetness of maltodextrin versus the simple sugar, sucrose (sugar found in your pantry):
Put 6 teaspoons (about 25g) of ordinary table sugar in ¼ cup of water. Label it ‘A’.
Take another cup and label it ‘B’. Add ¼ cup of water, but this time only put in 1 teaspoon of sugar.
Stir both cups until the sugar is dissolved. Drink each cup in its entirety. Are you able to comfortably finish the entire amount of cup ‘A’? Envision drinking cup ‘A’ in 80 F weather twenty miles into a marathon, keeping in mind that sweetness intensifies with increasing temperature. The high sugar taste is puckering. Cup ‘B’ however, is very neutral--slightly sweet, but easily drinkable. Maltodextrin has the sweetness equivalent to Cup ‘B’.
One last note on gel carbohydrates. When looking at the nutrition label and ingredient list on an energy gel packet, it’s easy to determine how many of the carbs come from maltodextrin and how many come from simple sugars. Companies are required to report the amount of carbohydrates in their product in a standard format on the nutrition facts label. The FDA requires that the total amount of carbohydrate be listed first, followed by a breakdown of the amount of sugars and fiber present.
Figure 6. Energy Gel Nutritional Facts Label
Using Figure 6 as an example, this particular energy gel contains a total of 20 grams of carbohydrate per packet. Of this 20 grams, 6 come from simple sugars and none from fiber. By simply subtracting 6 from 20 you get 14 grams of complex carbohydrates. The only ingredient on the product label that is a complex carbohydrate is maltodextrin, therefore, 14 grams (or 70%) of the carbohydrate in the gel is coming from maltodextrin, whereas 6 grams (30%) is coming from dextrose and fructose*. We unfortunately can’t tell how many grams of dextrose and fructose are individually contained in those 6 grams, but by looking at the ingredient list we do know that more dextrose is present than fructose because of the listing order. Ingredients are always listed in order of descending quantity.
*Note: Maltodextrins used in the energy gel industry by default contain a certain percentage of simple sugars, typically around 6-7%. Using the example above, maltodextrin is contributing a small amount of simple sugars (less than a gram) to the 6 gram total along with dextrose and fructose.