What is glucose-fructose syrup? (Q&A)
Carbohydrates | Sugars | 07 November 2011
Glucose, Fructose and Sucrose
Glucose is a simple sugar (monosaccharide) found naturally in many foods. Long chains of glucose molecules linked together form starch.
Fructose is also a simple sugar found in many foods and is an isomer of glucose (they have the same chemical formula C6H12O6, but their physical structures are different). Fructose is sometimes referred to as fruit sugar. Honey, tree fruits (such as oranges, apples etc), berries, melons, and some root vegetables, such as beets, sweet potatoes, parsnips, and onions, contain fructose, usually in combination with glucose and sucrose or table sugar. Sucrose is made up of glucose and fructose linked together in a 1:1 ratio.
What is Glucose-Fructose Syrup (GFS)?
Glucose-Fructose Syrup is a liquid sweetener used in the manufacturing of foods and beverages. GFS is composed of different simple sugars, mainly glucose and fructose, with varying compositions. The fructose content can range from 5% to 50%. If the fructose makes up more than 50% of the syrup, the name on the ingredient listing should read Fructose-Glucose Syrup. Fructose and glucose exist in their free form in GFS whereas in sucrose they are linked together.
Fructose is the sweetest of all naturally occurring sugars, including sucrose. Both fructose and sucrose are sweeter than glucose. A GFS with 42% fructose content is nearly identical in sweetness to table table sugar. Its sweetness and its ability to blend well with other ingredients are the main reasons GFS is used in the manufacture of foods and beverages.
Glucose-Fructose Syrup, Isoglucose, High Fructose Corn Syrup
In Europe, Glucose-Fructose Syrup is the official name used on ingredient labelling. This type of syrup is also sometimes referred to as isoglucose. The name isoglucose is used because the production process uses isomerisation enzymes. (See the next section: How is GFS made?)
Within the European Union (EU), the Sugar Regime regulates the allowed production quota. Production of GFS is currently limited to about 5% of total sugar production in the EU. Therefore, wide-scale replacement of sugar has not occurred in Europe and it remains a small market.
In the US, this type of product is more commonly produced with a 55% fructose content and is called High Fructose Corn Syrup (HFCS).
How is GFS made?
GFS is made from starch by first making a glucose syrup. The linked glucose molecules in starch are hydrolysed into free glucose molecules. Then, with the use of enzymes, some of the glucose is changed into fructose in a process called isomerisation. The starch source is chosen depending on local availability of the raw material suited for the starch extraction process. Maize was most commonly used in the past, but in recent years the use of wheat has increased as it is a locally more available source of starch. Sourcing of the raw material is mainly done from European origin.
Is GFS present in a lot of products?
In Europe the main calorie-containing sweetener used in the production of food and drinks is sucrose. As mentioned above, the production of GFS is capped in the European Union by the European Sugar Regime and hence produced quantities are limited. An additional factor in the choice of sugar sources used depends on the availability and the relatively close proximity of the raw material to the end user of the sweetener.
The nutritional properties of GFS
The human body derives its energy for maintenance and activity from 3 classes of substances: carbohydrates, proteins and fats. GFS is a source of carbohydrate.
In March 2010, the European Food Safety Authority’s Panel on Dietetic Products, Nutrition and Allergies (EFSA NDA Panel) published their scientific opinion on dietary reference values for the intake of carbohydrates, dietary fibre, fats and water. The Panel advised the following with regard to intake of carbohydrates and sugars:
- The intake of total carbohydrates - including carbohydrates from starchy foods such as potatoes and pasta, and from simple carbohydrates such as sugars - should range from 45 to 60% of the total energy intake for both adults and children.
- For added sugars (those not naturally found in foods), the Panel found there was insufficient evidence to set an upper limit. This is because the possible health effects are mainly related to patterns of food consumption – i.e. the types of foods consumed and how often they are consumed – rather than in relation to the total intake of sugar itself.
Functional advantages of GFS
GFS is used in foods and drinks for its sweetness and ability to blend well with other ingredients. In addition to these basic functions there are other qualities which have played a role in the creation of new consumer products. For example, a number of food products do not need additives for their conservation when GFS is used – an effect also observed with regular sugar. This helps to fulfil the needs of consumers when they desire products without additives. Furthermore, GFS may allow product textures beyond those achievable with sugar. By choosing the correct sugar composition it is possible to keep one layer in a product moist while another layer stays crispy.
Which foods and beverages contain GFS?
Because of the limited availability in Europe, the products in which GFS is used, are those where the sweetening power and other qualities are needed simultaneously. Examples of this can be found in baked goods, cereal products, confectionery, jams and preserves, yogurts and other dairy products, condiments (e.g. mustard and ketchup), canned and packed goods. The use of GFS in soft drinks has been limited as this application needs a fructose content of 42% or higher to give the desired sweetness and GFS is not available in sufficient quantities to be widely used in soft drinks. In the EU, soft drinks continue to be sweetened mostly with sucrose, when in the US, they are sweetened with HFCS.
Is GFS the same as sucrose (table sugar)?
Both GFS and sucrose contain glucose and fructose. Sucrose contains 50% of each, and the two sugar molecules are bound together. The glucose and fructose in GFS are not bound together, and the ratio of the two sugars can vary. The versions of GFS with the highest fructose content are usually composed of 42% fructose.
Studies have shown that the metabolism of glucose and fructose in the body is similar whether they are consumed in GFS or in sugar.
Does GFS contain more calories than sugar?
No, GFS and sucrose both contain 4 kcal per gram.
HFCS (GFS) in the News
Recently, study results obtained on the basis of a high quantity pure fructose diet are being extrapolated to HFCS (GFS). Consumption of fructose as the sole carbohydrate is highly unusual and not reflective at all of people’s habitual diets. Pure fructose is not the same as GFS. Fructose and glucose – the two main constituents of GFS and sucrose – are metabolised in different ways in the body, when consumed separately. But GFS is metabolised similarly to sucrose as these all contain fructose and glucose, in approximately the same proportion.
Is there a link between GFS consumption and obesity?
There is no causal link between the consumption of GFS and obesity. Many factors contribute to the development of obesity, yet nutritionists, health experts and researchers generally agree that the chief cause is an imbalance between calories consumed and calories burned. Excessive calories can be consumed as fats, proteins, alcohol or carbohydrates. Lack of physical activity also plays a significant role in promoting body fat accumulation and the development of obesity.
Recent reports have suggested that excess consumption of GFS may be responsible for the current obesity crisis in the U.S. However, obesity rates have also risen dramatically across Europe in the absence of a parallel rise in GFS intakes. This comparison renders a link between GFS consumption and obesity implausible.
Does Fructose affect feelings of fullness?
There have been some studies trying to show that fructose may not be as satiating (producing a feeling of fullness) as other sugars because it does not stimulate the hormones that affect hunger and food intake (such as insulin), and therefore would cause people to eat or drink more. However, a recent review concluded that the evidence for fructose being less satiating than glucose or GFS being less satiating than sucrose is not compelling.
Does the European Food Safety Authority (EFSA) have an opinion on fructose and satiety?
At the present time the European Food Safety Authority has not made a statement concerning fructose and satiety.
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