Stachyose is a functional tetraoligosaccharide that naturally exists in plants such as Labiatae, Fabaceae, and Scrophulariaceae, and belongs to α-galactooligosaccharides. The molecular weight of stachyose is 666.59, which is composed of 1 molecule of α-glucose, 1 molecule of β-fructose and 2 molecules of α-galactose. Its sweetness is only 22% of that of sucrose, and it has high thermal stability and solubility.  Stachyose has stable physical and chemical properties and special physiological functions, laying the foundation for its application in the field of functional foods.

Stachyose is a natural super-strong bifidus factor, which can regulate intestinal microbial flora, promote intestinal peristalsis, prevent and treat constipation, treat acute and chronic diarrhea, colitis, enhance the body's immunity, and assist in lowering blood pressure and blood fat. It also can prevent dental caries, promote the elimination of lead in the body, and treat subclinical hepatic encephalopathy (SHE). With the continuous exploration of its physiological functions and the vigorous development of the big health industry, stachyose has gradually become a new focus of research and development in the health food and functional food industries, and its application fields will continue to be explored.

Physiological functions of stachyose.

1. Regulate intestinal microbial flora and prevent intestinal mucosal damage. Stachyose is a functional oligosaccharide that cannot be decomposed by gastrointestinal digestive juices, but can be absorbed and utilized by probiotics such as Bifidobacterium and Lactobacillus in the intestines, which promotes the proliferation of beneficial microbial flora in the intestines and maintains intestinal micro-ecological balance, improve intestinal function.

2. Stachyose products have the effect of improving constipation and laxative for the human body.

3. Reduce inflammatory factors and regulate immune function. Stachyose is decomposed by bifidobacteria to produce immune active factors such as melibiose and mannotriose. These immune active factors can activate immune cells, reduce inflammatory factors, and promote immune regulation of the body.

Application of stachyose in food industry.

1. Application in dairy industry.

Stachyose is widely used in the dairy industry. Stachyose can stimulate the growth and activity of bifidobacteria, and it can be used as a prebiotic in the production of dairy products to develop functional dairy products. Stachyose can also be added to ordinary sterilized milk or modulated milk to increase its health function.

2. Application in flour products industry.

Noodle products are one of the staple foods in our country. The production process of different noodle products has different requirements on the quality of flour, and it is necessary to add quality improvers to prepare various special flour for noodle products. With the rapid development of the food industry and the improvement of people's requirements for a green and healthy diet, adding natural, non-toxic, nutritious and functional flour improvers has broad prospects. As an oligosaccharide, stachyose is known as "highly active bifidus factor", which can promote the rapid reproduction of intestinal probiotics and inhibit the growth of harmful bacteria. Adding stachyose to flour products can effectively improve the quality of flour, improve the nutritional value of flour, and endow flour products with functional properties. Stachyose has good viscoelasticity after absorbing water. As the amount of stachyose increases, it can significantly reduce the water absorption of flour, increase the fluidity of dough, and improve the stability time of dough. At the same time, stachyose can delay the speed of the aging of starch, and effectively improve the elasticity of the dough.

3. Application in fruit and vegetable processing industry.

During the drying process of fruit and vegetable raw materials, osmotic pretreatment is usually required to shorten the drying time and avoid browning. Currently, the commonly used osmotic fluids include glucose, fructose, sucrose, starch syrup, corn syrup, and malt syrup. The demand for low sugar urgently requires us to find new raw materials for permeate. Stachyose infiltration pretreatment can improve the quality of apple chips, increase their crispness, maintain their color, and avoid the decrease of total phenolic content of apple chips. The functional oligosaccharide stachyose is known as "super prebiotic", which can promote the significant growth of bifidobacteria, has good physical processing characteristics such as high solubility, acid resistance, and high temperature resistance, without any bad smell, is suitable for developing functional beverages, and has extremely broad application prospects in fruit and vegetable beverage processing. At present, stachyose is mainly used in the development of soy milk beverages, tea beverages, malt beverages, coffee beverages, fruit and vegetable juice beverages, vegetable protein beverages and solid beverages, and has become a new hot spot in the processing of fruit and vegetable beverages.

4. Application in health food.

At present, stachyose has been applied to health food in many countries and regions, and more and more products using stachyose as health food raw material have been approved. This product using stachyose as a health food raw material can improve gastrointestinal function, improve sleep, enhance immunity,and delay aging.

Conclusion and outlook.

Stachyose, as an emerging functional oligosaccharide, has attracted much attention at home and abroad. At present, the efficacy and mechanism of stachyose have been deeply studied at home and abroad, and it is widely used in the food industry. In the future, the application of stachyose in the food industry will have a broader space, and its application will become an important research direction.