Sweet, tasty and healthy: The new essence of juice?

Many people like drinking fruit juice, which is both a good and bad thing. Fruit juice contains a number of beneficial vitamins but often has high sugar and low fiber contents. The challenge is to increase the nutritional value of the juice without spoiling the taste. A team of scientists that included researchers from Aarhus University devised a solution to the problem of combining sweetness with healthiness by adding stevia for sweetness and β-glucans for fiber with a dash of lime to adjust the taste.

Super sweetness joins fiber for health

A high intake of sugar is one of the factors contributing to obesity and lifestyle diseases, but cutting out sugar can be difficult. To satisfy our desire for something sweet while limiting our consumption of sugar, a natural sweetener called stevia can be used.

- Stevia is the only approved natural sweetener in Europe. From a health and technological viewpoint, the effects of using stevia have been purely positive, explains postdoc Line Holler Mielby from the Department of Food Science at Aarhus University.

Unfortunately, a characteristic of stevia is its effect on taste. Juice containing stevia has a tendency to leave a bitter aftertaste.

Earlier research results have shown that fiber in food has a number of health-promoting effects. fiber products that have a positive effect on health include β-glucans -- which are naturally occurring in oats, for example. However, β-glucans also have an adverse effect on flavour in that they give the food product a slightly metallic and stale smell.

The sensory experience is important

Foods should not only be healthy in order for consumers to buy them. They should also give the consumer a good sensory experience.

- Foods should have satisfying sensory characteristics, since these characteristics will determine whether the consumer will buy the product again. The product should leave a good all-round impression, explains Line Holler Mielby.

Adding healthy fiber and low-calorie sweeteners to food will not work if they have a negative effect on the flavour. A remedy has to be found for this and in this instance the choice fell on lime. In the study the scientists used an apple-cherry juice to which varying quantities of lime, β-glucans and stevia were added. The aim was to characterise the sensory experience of the juice.

The results showed that the addition of lime to the apple-cherry juice could counterbalance the adverse impact on taste of the stevia and β-glucans. The taste of lime in the juice concealed not only the aftertaste of stevia but also the smell of staleness and metals imparted by the β-glucans and improved the experience of drinking fruit juice containing β-glucans.

- With the increasing popularity of functional food, it would be relevant to examine the effects in other food products such as breakfast cereals that have a high sugar and low fiber content. In relation to the addition of β-glucans to food it would also be relevant to examine other eating experiences, for example satiety, says Line Holler Mielby.