GOS is the latest prebiotic to boost food health

Over the past decade, there has been an unprecedented increase in consumer awareness of gut-induced immunity and digestive health, leading to great interest in prebiotics and ingredients that influence gut microflora. The number of new product introductions with prebiotics has steeply increased over the last four years. While probiotics are predominantly used in fermented dairy products, the use of prebiotics has expanded into other food categories. For instance, the introduction of galacto-oligosaccharides (GOS) into baby foods has been very successful.

Prebiotics are defined as non-digestible food ingredients that beneficially affect the host's health by selective stimulation of growth of one or a limited number of species of bacteria in the colon. Vivinal GOS, from FrieslandCampina Domo, is derived from lactose, and consists of a galactose polymer with a glucose end unit. GOS are naturally present in mother's milk. Clinical studies show that Vivinal GOS has several health benefits, including improvement in digestive health, immune support and improved mineral absorption.

This article, however, focuses on the ingredient's sensory and formulation aspects.

Functional characteristics

Vivinal GOS is a versatile, functional ingredient, suitable for a broad range of food and beverage applications. It is sold as a syrup, with a high dry matter content (75 per cent) or as a powder. It is instantly dispersible and clear in solution, and so can be easily handled in various food and beverage systems. It has a neutral, slightly sweet taste profile, with low caloric density (2kcal/g). This makes it very easy to add to formulations.

It is heat and acid stable, during both processing and storage. Some other prebiotics, such as fructo-oligosaccharide s(FOS), become hydrolysed under similar conditions. Stability studies show that Vivinal GOS is not hydrolysed by heat or low pH, even when stored for up to six months at ambient conditions (See Figure 1). This ensures that adequate and effective amounts of the ingredient are retained in the product during the full shelf life. There is no need to increase initial dosages to compensate for functionality losses during shelf life, resulting in an optimal cost in use.

Figure 1. Stability of GOS vs FOS in soft drink model, pH 3, ambient storage

Sensory effects

Any addition of ingredients will have an impact on sensory properties of a product. That goes for prebiotics as well, especially as they act as both sweetener and texturiser. This sometimes causes grittiness or chalkiness, negatively affecting sensory quality. Sensory evaluation trials with plain yoghurt comparing Vivinal GOS, scFOS and lcFOS (inulin) showed significant differences in their sensory effects. GOS enhanced sweetness and improved the creamy taste of the yoghurt, to a much greater extent than inulin or FOS, without negative side effects such as roughness or filming (See Figure 2).

Figure 2: Sensory profiling of prebiotics in plain yoghurt. GOS enhances sweetness and creaminess.

These results clearly show that Vivinal GOS is a viable prebiotic for yoghurt and dairy applications. It is stable during processing and shelf life, and enhances sensory profiles. It can be added in all stages of production, as the syrup blends in very easily. In fruit yoghurts, for instance, it can be added to the fruit base, enabling more flexibility in the yogurt production process.

The positive flavour effect of this GOS is not only limited to dairy. In orange juices, it enhances fresh orange-peel flavours and reduces oxidation markers. This in turn boosts the overall fruit flavour. Other prebiotics show opposite effects.