As people pay more and more attention to dietary structure and nutritional needs, functional oligosaccharides such as fructooligosaccharides (FOS) and galacto-oligosaccharides (GOS) have become important basic raw materials and food additives due to their low sweetness, low energy, low absorption, promotion of intestinal probiotics growth, regulation of intestinal microecology, and enhancement of body immunity. They are widely used in the food industry, especially the dairy industry.

Fructo-oligosaccharides and galacto-oligosaccharides

FOS is composed of fructose and glucose connected by β-2,1 glycosidic bonds and cannot be digested by enzymes in the digestive tract. FOS is widely present in many plants, such as potatoes, onions, bananas, Jerusalem artichokes, rye, etc.

FOS has good solubility and thermal stability. Compared with sucrose, it has a purer sweetness and lower sweetness. It has certain effects on improving food taste, extending product shelf life, promoting the growth and reproduction of bifidobacteria, and promoting the absorption of trace elements.

GOS is composed of galactose or glucose linked to 1 to 7 galactosyl groups. The GOS content is highest in human breast milk, and is lower in animal milk.

Since the digestive system of newborns is still in the development stage, the establishment of probiotic flora in infants depends largely on the GOS component in breast milk. Therefore, GOS is generally added to the nutritional ingredients of infant formula to enhance the digestive ability and immune level of infants.

In addition, GOS is a nutrient source and proliferation factor for beneficial bacteria such as bifidobacteria and lactobacilli in the human intestine, and plays a good role in promoting the establishment of intestinal microecology.

Research progress on the efficacy of oligosaccharides

Regarding the research on the efficacy of functional oligosaccharides FOS and GOS, it was found through literature search that due to differences in test populations, age groups, clinical trial methods and purposes, clinical trial cycles and other factors, there are certain differences in the clinical efficacy of FOS and GOS. Functional oligosaccharides FOS and GOS are mainly used in clinical research to improve intestinal flora and gastrointestinal symptoms. Generally speaking, the effective dose will gradually increase with age; in addition, clinical trials have shown that the clinical results of FOS and GOS are more effective when used in a certain proportion.

Application of functional oligosaccharides in dairy products

Functional oligosaccharides have obvious advantages in regulating immune function, increasing the number of beneficial intestinal bacteria, and improving mineral absorption. They are also widely used in infant formula, children's milk, yogurt, and milk beverages.

1. Application of fructooligosaccharides and galacto-oligosaccharides in infant formula

Functional oligosaccharides are good nutritional fortification ingredients in infant formula. Their addition to milk powder has gone through a process from single to multiple. At present, the prebiotics added to most products are mainly FOS and GOS. In 2004, Abbott was the first to add functional oligosaccharides to its infant formula, which had a significant impact on the domestic infant formula market. With the improvement of health awareness among consumers, functional oligosaccharides have become a selling point for infant formula for a long time. Currently, functional oligosaccharides in infant formula sold on the market are mainly added in the form of FOS, GOS, and GOS/FOS.

2. The application of oligofructose and oligogalactose in children's milk

Children's milk is essential for adolescents aged 3 to 14 who are in the critical period of development. In addition to protein and calcium in milk, most children's milk contains key nutrients such as vitamin D and DHA, which can promote children's bone and intellectual development.

As parents pay more attention to children's immunity, the concept of functional prebiotics has gradually become known to consumers. In the children's milk sold on the market, Future Star Bone and Jiazhi have added FOS and GOS; Nutricia Hi-Q3 Plus Prebio 4 stage children's milk in the Thai market also has added FOS and GOS ingredients.

3. Application of fructooligosaccharides and galacto-oligosaccharides in fermented milk

At present, consumers’ demand for fermented yogurt is not only satisfied with its taste. The functionalization of fermented milk and the segmentation of consumer groups have gradually become its development trend. Functional food raw materials are widely used in fermented dairy products.

Taking enhancing immunity as an example, FOS and Bifidobacterium BB-12 are added to Guanyile milk to enhance intestinal immunity by adding both prebiotics and probiotics; oligofructose powder and Bifidobacterium breve powder are added to Guangming Jianneng probiotic yogurt to enhance immunity and promote digestion; FOS (content ≥1%) is also added to pure yogurt to regulate the intestinal environment and enhance intestinal kinetics; Japan's Brighten smooth contains tens of billions of probiotics and GOS, which has a good protective effect on the intestines of pregnant women, lactating women and infants.

4. Application prospects of fructooligosaccharides and galacto-oligosaccharides

FOS and GOS have many incomparable advantages over other sugars. They are a new type of sugar source that combines nutrition and health care. They have broad application prospects in ordinary foods, health products, special medical foods, and animal feeds.

FOS has a low calorific value and good thermal stability. It can replace the sucrose currently widely used in baked foods such as bread, cakes, and Chinese desserts. It helps to improve the color and taste of the products and enhance the healthy positioning of the products.

We can also consider adding FOS to ordinary beverages and wines to meet taste requirements while adding more functional options.

FOS and GOS have been widely used in health products, but they are mainly used to protect the gastrointestinal function. Physiological studies have shown that they also play an important role in mineral absorption, lipid metabolism, etc. Therefore, in the development of health products that supplement iron, zinc or promote lipid movement, it is possible to consider adding oligosaccharides such as FOS and GOS to exert their synergistic effects.

FOS has the effect of proliferating probiotics. Adding a small amount of FOS to fermented products can increase the number of lactic acid bacteria and shorten the fermentation time. It can be considered for use in the fermentation process of products such as yogurt, cheese, kimchi, soy sauce, and beer.