Inulin has proven effects on reducing glycaemic response while replacing sugars, reports Elaine Vaughan, Chief Science Officer at Sensus
Glycaemic response refers to the changes in blood glucose levels that occur as a consequence of eating a specific food. Different foods create different glycaemic responses. High-fibre carbohydrates elicit a low glycaemic response that can support better blood glucose management. Chicory root fibre — a natural, prebiotic, soluble dietary fibre — is one of these. And, as a ‘natural’ sweetener, it also reduces the amount of processed sugar needed in food products while, at the same time, enhancing taste.
Excessive sugar intake has been linked with obesity, type 2 diabetes, increased ageing, cardiovascular disease and even certain forms of cancer. With alarming increases in the prevalence of obesity and diabetes in particular, dietary sugar reduction has become a major concern.1 More and more people are considering glycaemic response when choosing the foods they eat.
Each time we consume food that contains starch and sugars, these ingredients are broken down during digestion into simple sugars such as glucose and fructose. These sugars are then transported via the bloodstream to our organs and tissues, which convert them into energy. The uptake of glucose in our bloodstream causes the blood glucose level to rise. This rise in blood glucose after a meal is the so-called postprandial glycaemic response, shown schematically in Figure 1 (red line).
The increase in glucose levels of the blood leads to another physiological response, the secretion of the hormone insulin from the pancreas (the orange line in Figure 1). This hormone conveys a signal to our organs, such as our muscles, to take up the glucose from the blood, which leads to a lowering of the blood glucose level. In fact, this is a well-designed control and steering mechanism of our metabolism. Things can go wrong when we sustain high glucose levels (and, in turn, high insulin levels) for a long time. The organs can become resistant to insulin, the pancreas eventually produces less and type 2 diabetes or obesity results.
Not all foods trigger the same glycaemic response in terms of level and duration of the blood glucose peak that follows their ingestion. The specific glycaemic response of different foods is known as its glycaemic index (GI) or glycaemic load (the total glycaemic response of a food or meal). These measurements can be compared for different foods to assess their effect on blood glucose. Low glycaemic response foods lead to a lower and slower increase in blood glucose levels.
Chicory root fibres such as inulin and oligofructose are high-fibre carbohydrates that are not broken down or digested into simple sugars by the upper digestive tract, but are fermented by gut microbiota in the intestinal tract. As a result, they do not affect blood glucose level and trigger a minimal glycaemic response.2
Fortunately, both inulin and oligofructose are well suited to replace sugar in a range of food products. By using these ingredients in food products, food manufacturers can lower the glycaemic response of the food. Both oligofructose and inulin make a good sugar substitute, especially to replace the bulking properties of sugar.
That said, though, oligofructose has a sweeter taste than inulin. However, the final taste and texture of the product with inulin or oligofructose will not be that different compared to the 'full-sugar' product, but the product will cause a lower postprandial glycaemic response. An additional benefit is that the use of oligofructose or inulin increases the amount of dietary fibre, helping consumers to increase their fibre intake. This is a welcome added benefit of using these ingredients as the intake of fibre is well below the recommended rates nearly everywhere in the world.
Sensus, one of the world’s leading suppliers of chicory root fibres, sources inulin and oligofructose from natural chicory roots. It has studied the glycaemic response of its products and found a reduced glycaemic response associated with its products. Whereas glucose has a GI of 100, and sucrose, a somewhat lower GI of 68, both pure inulin and oligofructose have a GI of almost 0.3
They are naturally sourced sweet-tasting fibres that can help to reduce the amount of processed sugar (and fat) needed within food products and also enhance their taste and texture. In addition, they have other significant, scientifically proven health benefits. As high fibre carbohydrates, they can help to enhance bowel health. And, with a low calorie content, the ingredients can support weight reduction.
Sucrose, glucose syrup and other sugars are used in a wide range of food applications because of their functional properties. For example, they add sweetness, function as a bulking agent, improve mouthfeel and can be used for crystallisation or to improve the shelf-life of the final product by decreasing water activity, thereby reducing microbial growth.
The perception of sweetness in food products is affected by a combination of the sweetness level and the sweetness profile. For the latter, this means how quickly the sweetness appears, the intensity of the peak and how long the sweetness lasts until it disappears. When using inulin and oligofructose as sugar replacers, their relative sweetness levels compared with sucrose fall between 0% and 50%.
Although inulin and oligofructose are sweet, they are around 30–50% as sweet as sucrose. Generally, consumers do not notice a relative change in sweetness of 5–10%. However, this depends on the type of application (liquid versus solid foods, for example) along with the fat content of the food product. To compensate for lower sweetness levels in a sugar-reduced formulation, food manufacturers can combine inulin or oligofructose with a high-intensity sweetener, such as sucralose or steviol glycosides.
This combination also helps to reduce the undesired off- and/or aftertaste associated with most high-intensity sweeteners. In fact, by using a combination of a high-intensity sweetener with inulin or oligofructose, food manufacturers can also optimise the taste profile of their food products. Moreover, research shows that inulin and oligofructose have valuable synergies with high-intensity sweeteners. This means that the combination of inulin or oligofructose with a high-intensity sweetener results in even more sweetness than simply adding the sweetness of inulin to the high-intensity sweetener.
Award-winning, UK ice cream manufacturers, Taywell Ice Creams, use chicory root fibre as an ingredient in their new range of healthy ice cream. The ‘Sweet Rebellion’ range is free from processed sugar (and, therefore, has a low GI), gluten, artificial additives, colours and stabilizers. “Our aim was to change ice cream from a treat into a healthy product,” explained Alistair Jessel, Owner of Taywell Ice Creams. 'Chicory root fibre adds sweetness and does not negatively influence taste, but enhances the texture and scoopability. Our customers say that it makes them feel more full and satisfied after eating our ice cream. Being a solid fibre, chicory root fibre does not add calories or sugar or fat to the product, or the waistline! It is a highly beneficial ingredient for use in a ‘new world’ where obesity is a serious issue.'
EFSA has given a positive opinion for a lower glycaemic response health claim for inulin and oligofructose from chicory roots that will come into effect in the coming year. Food manufacturers can use these functional ingredients to develop food products that support healthy blood glucose levels. Furthermore, with the various sweetening and texturizing properties of inulin and oligofructose, Sensus research shows that equivalent healthier food products with reduced sugar content can be manufactured.
Moreover, inulin and oligofructose in combination with high-intensity sweeteners can be used to produce great-tasting food products with a lower or even zero sugar content. Alastair Nicoll, Brenntag Food & Nutrition, said: 'We are noticing a definite upward demand in the industry using chicory root as a dietary fibre as well as a sugar and fat replacement, fitting the clean label trend perfectly.
Inulin and oligofructose are already incorporated into a wide variety of available food products, including selected brands of dairy foods, bread and bakery products, confectionery and beverages. 'By choosing products that contain inulin and oligofructose, consumers can enjoy healthier, tasty products with lower sugar content,' said Elaine Vaughan, Chief Science Officer at Sensus. 'We hope many more food manufacturers will utilise them in the future to support the efforts of people, who are trying to improve their diet and health.'
1. www.who.int/mediacentre/factsheets/fs312/en/ and www.who.int/mediacentre/factsheets/fs311/en/.
2. D Meyer, 'Inulins for Product Development of Low GI Products to Support Weight Management' in H. Salovaara, et al. (Eds.), Dietary Fibre Components and Functions (Wageningen Academic Publishers, Wageningen, the Netherlands, 2007) pp 257–270.