Monster sugars — The Sweetening Journey (part 3 of 6)

Glucose syrup, isoglucose, and invert sugar are bulk sweeteners produced industrially through chemical processes during which starch or sugar is transformed into something that replaces the sweetness and volume of sugar. In this third article of six of our sweet journey, we learn more about these alternatives to sugar.

30 October 2020 •

Our sweet jour­ney con­tin­ues. We have left sug­ars and sug­ar alco­hols behind, and have now arrived at the third stop. Here we find a colour­ful mix of high­ly processed, sug­ar-like prod­ucts. We’re talk­ing about glu­cose syrup, isoglu­cose, invert sug­ar, and the like.

Bulk sweeteners

Ingredients that are about as sweet as sug­ar and that takes up about the same amount of vol­ume are some­times called bulk sweet­en­ers. Sweeteners, as they bring sweet­ness to the prod­uct. Bulk, as they, just like sug­ar, have a rel­a­tive­ly low sweet­ness in rela­tion to their weight and vol­ume and is there­fore need­ed in larg­er amounts.

The sug­ar types and sug­ar alco­hols we have already looked at in the pre­vi­ous arti­cle are exam­ples of bulk sweet­en­ers. But there are more of them. The remain­ing ones are pro­duced indus­tri­al­ly through chem­i­cal process­es in which starch or sug­ar is trans­formed into some­thing sim­i­lar to sug­ar or syrup. In this arti­cle, we will look clos­er at four of them.

Glucose syrup is also known as just glu­cose. It’s a liq­uid blend that gets its sweet­ness from glu­cose, mal­tose and mal­todex­trin, which are all the result of split­ting starch. Sometimes fruc­tose is added to increase the sweetness.

Glucose-fruc­tose syrup is a glu­cose syrup with more than 5 per cent added fruc­tose but with more glu­cose than fruc­tose. Not to be con­fused with fruc­tose-glu­cose syrup.

Isoglucose is also called fruc­tose-glu­cose syrup, high fruc­tose corn syrup, or HFCS for short. It’s a liq­uid blend of glu­cose, fruc­tose and mal­todex­trin, pro­duced by split­ting starch to glu­cose syrup and then turn­ing mal­tose to fructose.

Invert sug­ar is a liq­uid blend of glu­cose and fruc­tose, pro­duced from reg­u­lar sugar.

Bulk sweet­en­ers and their sweet­ness rel­a­tive to reg­u­lar sug­ar, gly­caemic index (GI) with white bread as a ref­er­ence, and ener­gy content.
Bulk sweet­en­er Sweetness GI Energy
Glucose syrup 30–60 % 90–150* 4 kcal/​g
Glucose-fruc­tose syrup 35–100 %* 90–150* 4 kcal/​g
Isoglucose 80–100 % 81–95 4 kcal/​g
Invert sug­ar 120 % 84 4 kcal/​g
* Estimation in absence of a reli­able source.

Glucose syrup

Glucose syrup is pro­duced from starch, which often comes from pota­toes, wheat or corn.

Starch is chains of glu­cose mol­e­cules. By dis­solv­ing starch in water and adding acid or enzymes, or both, and heat­ing the blend, starch is bro­ken down into small­er chains of glu­cose mol­e­cules (mal­todex­trin) which in turn is bro­ken down into even small­er ones, and so on. This is called hydrol­y­sis.

The result is glu­cose syrup – a blend of glu­cose, mal­tose (two glu­cose mol­e­cules) and mal­todex­trin. Glucose syrup can thus be described as the result of hydrol­y­sis of starch.

The qual­i­ty of the glu­cose syrup is cal­cu­lat­ed as a per­cent­age by mass of the dry mat­ter. This per­cent­age is called dex­trose equiv­a­lent (DE).

Complete hydrol­y­sis turns all starch into glu­cose (DE = 100) but also gives rise to bit­ter degra­da­tion prod­ucts. Glucose syrup is most com­mon­ly used with DE = 42 and DE = 70. To be termed gly­cose syrup DE must be at least 20. At below 20, it is referred to as mal­todex­trin.

Glucose syrup is used more and more as it’s cheap­er than sug­ar. It is also used to pre­vent crys­talli­sa­tion of reg­u­lar sug­ar, to increase vis­cos­i­ty and to pre­serve moisture.

Glucose-fructose syrup

Glucose is less sweet than reg­u­lar sug­ar. To com­pen­sate this there is a glu­cose syrup with added fruc­tose, which is sweet­er than reg­u­lar sugar.

If the glu­cose syrup con­tains more than 5 per cent fruc­tose but the lev­el of glu­cose is larg­er than the lev­el of fruc­tose, the result is called glu­cose-fruc­tose syrup. All count­ed as dry matter.

Isoglucose (fructose-glucose syrup)

Glucose syrup is also the start­ing point for the pro­duc­tion of isoglu­cose, also known as fruc­tose-glu­cose syrup. Isoglucose which is pro­duced from starch from corn is called corn syrup, or HFCS (high fruc­tose corn syrup).

The pro­duc­tion of isoglu­cose starts with starch which is hydrol­ysed with acid and two dif­fer­ent kinds of enzymes. The result is glu­cose syrup, to which enzymes are added which cause the atoms to realign so that the glu­cose turns into fruc­tose. This is called iso­meri­sa­tion.

The result is an isoglu­cose which con­sists of 42 per cent fruc­tose, 50–52 per cent glu­cose and 6–8 per cent maltodextrin.

With high-per­for­mance liq­uid chro­matog­ra­phy, the lev­el of fruc­tose can be con­cen­trat­ed to 90 per cent. This is rarely used in foods.

Finally, you can blend a 42 per cent isoglu­cose and a 90 per cent isoglu­cose to a blend with 55 per cent fruc­tose. This blend is most sim­i­lar to sug­ar in sweet­ness. It’s used in for exam­ple sodas.

Invert sugar

Invert sug­ar is also a blend of glu­cose and fruc­tose. It’s pro­duced in a sim­i­lar way to glu­cose syrup but starts with reg­u­lar sug­ar instead of starch.

Regular sug­ar has mol­e­cules that are com­posed of glu­cose and fruc­tose. By dis­solv­ing sug­ar in water and adding acid, enzymes, or both, and heat­ing the blend, the sug­ar is bro­ken down into glu­cose and fructose.

The result is invert sug­ar, con­sist­ing of 50 per cent glu­cose and 50 per cent fruc­tose. Invert sug­ar can thus be described as the result of hydrol­y­sis of reg­u­lar sugar.

Invert sug­ar is indus­tri­al­ly pro­duced as a 65–73 per cent aque­ous solution.

Invert sug­ar is just as sweet as reg­u­lar sug­ar, but it has a bet­ter preser­v­a­tive func­tion than sac­cha­rose. It’s also used to con­trol crys­talli­sa­tion in sug­ar con­fec­tionery products.

Worse than regular sugar

Glucose syrup and isoglu­cose are cheap­er than reg­u­lar sug­ar. Invert sug­ar is more expen­sive but has a bet­ter preser­v­a­tive func­tion, lim­its crys­talli­sa­tion and has anoth­er few aces up its sleeve. So that makes bulk sweet­en­er bet­ter than reg­u­lar sug­ar, doesn’t it?

Absolutely not!

From a health per­spec­tive, they are even worse than reg­u­lar sugar.

Strictly, glu­cose syrup has the same num­ber of calo­ries as reg­u­lar sug­ar, but as glu­cose syrup only has 30–60 per cent of the sweet­ness of reg­u­lar sug­ar, you need up to 2.5 times more glu­cose syrup than sug­ar to get the same sweet­ness. This means 2.5 times more calories.

When it comes to GI it gets even worse. Glucose syrup con­sists prac­ti­cal­ly exclu­sive­ly of the two reg­u­lar sug­ar types which have a high­er GI than reg­u­lar sug­ar. Glycaemic index for glu­cose is 138 and for mal­tose 150. That’s 50 and 63 per cent respec­tive­ly, high­er than reg­u­lar sugar.

Isoglucose and invert sug­ar are both a blend of about equal parts glu­cose and fruc­tose – just like reg­u­lar sug­ar. But where reg­u­lar sug­ar is digest­ed in your body, isoglu­cose and invert sug­ar are digest­ed in the fac­to­ry. The glu­cose and fruc­tose are freed and can eas­i­ly be digest­ed by the body, where they will increase the blood sug­ar lev­el and turn into fat, respectively.

‘Monster sugars’

More and more con­sumers are avoid­ing high­ly processed bulk sweet­en­ers. It’s not the high lev­el of pro­cess­ing that goes into pro­duc­ing them that is the scari­est part, but new research that in media is pre­sent­ed as alarm­ing reports on ‘mon­ster sugars’.

Terrifying stuff! Let’s keep looking.

In our next arti­cle, the jour­ney con­tin­ues. Then we will look at arti­fi­cial sweeteners.

Don’t miss the oth­er arti­cles in the Sweetening Journey collection!

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