What Is the Use of Stachyose in Beverages?

Stachyose is a functional oligosaccharide that occurs naturally in the legume family. It consists of one molecule of fructose, one molecule of glucose and two molecules of galactose. The main functional group of raffinose is the α-1,6 glycosidic bond on the glucose side. Its taste is similar to that of sucrose, but its sweetness is only 22% that of sucrose. Because of its low absorption rate and lack of effect on blood glucose levels, it can be used as a good alternative to sucrose.

Stachyose can significantly promote the proliferation of beneficial bacteria in the intestines and is known as a “natural super bifidus factor” [1]. Gao Peng et al. [2] found through human food trials that the minimum effective dose of xylitol is 0.5 g·d-1 and the maximum dose without effect is 10 g·d-1. The study found that the recommended daily intake of xylitol is 0.5 to 3 g·d-1. Guo Meili et al. [3] proved through a series of toxicological experiments that feeding rats with stachyose for 90 consecutive days did not cause abnormalities in related indicators, and no obvious toxic reactions were found, providing a reliable basis for the application of stachyose in food. Stachyose can exert better health-care functions at lower doses, and it has a pure taste and is easily soluble in water, making it very suitable for use in the functional beverage industry.

1 Physical and chemical properties of stachyose

The molecular formula of stachyose is C24H42O21 and the molecular weight is 666.59. The molecular structure is shown in Figure 1. Pure stachyose is a white powder with a refreshing taste. It is highly soluble in water and insoluble in organic solvents such as ethanol. It loses water at 115 °C under vacuum, and the anhydrous melting point is 167–170 °C [4].

2 Health benefits of stachyose

2.1 Prevention of tooth decay

Tooth decay is caused by acid production and the reproduction of Streptococcus mutans, a type of oral microbe, after it ferments sugar substances, which then corrodes the teeth. Since Streptococcus mutans cannot break down the α-1,6 glycosidic bond in stachyose, it cannot use the nutrients in stachyose and will not cause tooth decay.

2.2 Bifidobacteria proliferation and regulation of intestinal flora

Stachyose cannot be broken down by gastrointestinal digestive juices and can be directly utilized by intestinal microorganisms. Bifidobacteria preferentially degrade and utilize non-digestible oligosaccharides in the intestine. If multiple available oligosaccharides are present at the same time, xylose will be preferentially consumed [5]. Therefore, Stachyose can more directly act on bifidobacteria.

Huang Xiaochun [6] found that the use of xylooligosaccharides alone can increase the number of bifidobacteria by 40 times, and the effective amount is only 1/5 of that of fructooligosaccharides. Shu Guowei et al. [7] found in experiments that compared with xylooligosaccharides and galacto-oligosaccharides, the addition of 0.2% (w/v) stachyose to MRS medium can effectively lower the pH of the medium and increase the turbidity (OD600). It was found that the decrease in pH and the increase in OD600 were both manifestations of the massive proliferation of Bifidobacterium bifidum BB01. LI[8] found through human food trials with fructooligosaccharide particles that fructooligosaccharides can effectively promote the growth of beneficial bacteria in the human intestine, inhibit the growth of harmful bacteria, regulate the intestinal environment, and improve the stability of the intestinal microecology.

2.3  Laxative

Bai Yuxia et al. [9] found that rehmannia polysaccharide has a significant laxative effect. The molecular structure of rehmannia polysaccharide contains many hydroxyl groups, which can absorb water in the intestines well and increase the moisture content of the feces. Xi Zhaoyan et al. [10] found through clinical observation of constipated patients that fructooligosaccharides can effectively promote the proliferation of beneficial intestinal bacteria, lower intestinal pH, and promote intestinal peristalsis [11]. LI et al. [8] also showed that fructooligosaccharide granules can increase the frequency of bowel movements in constipated patients and improve their intestinal function. Yu Chaozhou et al. [12] found in a study of the effects of a compound of fructooligosaccharides and konjac glucomannan on the intestines that taking the compound in a certain ratio can significantly promote small intestinal motility in mice, shorten the time to the first bowel movement, increase the amount of bowel movements in mice within 6 hours, and has a good laxative effect. This effect is partly due to the fact that stachyose is stable under acidic and high temperature conditions, has a refreshing taste and no peculiar smell, and its physical and chemical properties fully meet the production process requirements of beverage products.

Konjac glucomannan has a good water absorption and swelling effect [13], and on the other hand, stachyose has the effect of increasing beneficial bacteria and promoting intestinal peristalsis to improve intestinal function.

2.4 Lowering blood lipids and blood pressure

Cao Chunfeng et al. [14] found that after 8 weeks of taking Fructo-oligosaccharide capsules, the blood concentrations of low-density lipoprotein cholesterol and total cholesterol were reduced in 42 hyperlipidemic patients who underwent dietary intervention, and no adverse reactions were observed. The study found that the organic acids produced by bifidobacteria when breaking down fructose can lower the pH of the intestines. This chain reaction can inhibit cholesterol synthesis. The study also found that some probiotics in the intestines can reduce cholesterol to steroid substances and excrete them from the body, reducing or interfering with the intestinal reabsorption of cholesterol, thereby lowering the level of blood cholesterol in the body and improving lipid metabolism disorders.

Zheng Jianxian et al. [15] also found that the diastolic blood pressure of the human body is significantly negatively correlated with the proportion of bifidobacteria in the feces. Xylitol can effectively proliferate bifidobacteria in the intestine, help bifidobacteria establish an advantage among the many species of bacteria in the intestine, and stabilize blood pressure. Studies have shown that after 6 weeks of daily intake of 10 g of fructooligosaccharides, the diastolic blood pressure of patients decreased by an average of 799.7 Pa [16], indicating that fructooligosaccharides have a blood pressure-lowering effect.

2.5 Improves immunity

Studies abroad have confirmed that the α-glycosidic bond structure is involved in immune processes based on the molecular mechanism of the sympathectomy receptor, which gives mannose the function of preventing pathogens and regulating the immune system [16]. Immune active factors in the human body can activate immune cells and promote the body's resistance to external pathogens. In the intestine, fructooligosaccharides are broken down by bifidobacteria to produce immune factors such as mannose and raffinose, so fructooligosaccharides are of great help in improving the body's immunity [17].

Chen Chao et al. [18] found in experiments that giving itchy mice fructooligosaccharides can reduce the number of itching episodes and significantly reduce the duration of itching. Ma Yingying et al. [19] also found that stachyose can inhibit foot swelling and anti-inflammatory pain, and it can significantly reduce the content of inflammatory factors in the serum and the index of immune organs. Li Zhifu et al. [20] found that the Chinese medicine extract stachyose has a therapeutic effect on stress-induced intestinal dysfunction. Yi Zhonghua et al. [21] found that adding a small amount of stachyose to poultry feed can maintain maintain the immune function of poultry. The above all shows that fucose has the effect of improving immunity.

2.6 Liver protection and detoxification

Fucose can promote intestinal peristalsis, proliferate beneficial bacteria, reduce the retention time of toxins in the intestines, accelerate the excretion of toxic and harmful substances, and reduce the burden on the liver. By affecting certain enzymes, stachyose reduces the activity of harmful enzymes in the intestines and reduces the production of methylphenols and other products in the intestines. Gui Jinhua et al. [22] found in experiments that stachyose can reduce the content of IL-6 in the body of rats with cirrhosis, improve the intestinal environment of cirrhotic rats, reduce the content of endotoxins in the plasma and relieve pathological liver damage [23]. Li Ruijun et al. [24] also found that stachyose has a good preventive effect on clinical hepatic encephalopathy. After observing 30 patients, they found that after treatment with stachyose, the latencies of the BAEP Ⅲ wave and Ⅴ wave and the VEP1000 latency were significantly shorter than before treatment, proving that stachyose can effectively treat subclinical hepatic encephalopathy [25].

Fructooligosaccharides can promote the synthesis of B vitamins and the absorption of calcium, iron, zinc and other elements. These substances can reduce the absorption of lead [26]. In addition, fructooligosaccharides themselves have a certain chelating effect on lead. While promoting the absorption of other substances, they can also inhibit the absorption of lead and accelerate the excretion of harmful metals [27].

2.7 Antitumor

Jia Shaohua et al. [28] demonstrated through in vitro and in vivo anti-tumor activity screening that stachyose (26.45% content) has a significant inhibitory effect on human liver cancer HepG-2 cells and human gastric cancer SGC-7901 cells, and also significantly enhances the anticancer effect of cyclophosphamide (p < 0.05). Fructosyl trehalose can inhibit the proliferation of colon cancer cells Caco-2, reduce the expression of the oncogene B-cell lymphoma/leukemia-2 gene, and increase the expression of X protein and cytochrome C, thereby increasing the expression of the apoptosis protease caspase 3 and caspase 9, and achieving the effect of anti-colon cancer [29].

3 Application of stachyose in beverages

Stachyose is widely used in food. Japan was the first country to develop a series of oligosaccharide-based products, mainly for use in beverages, but there are relatively few stachyose-related products. The physiological activity of stachyose is shown in Figure 2. It has stable physicochemical properties, good thermal stability under acidic conditions, and a moderate sweetness and refreshing taste, making it very suitable for use in beverages and as a substitute for some sucrose. Compared with other functional oligosaccharides, stachyose can be used in smaller amounts. Only 0.5 to 3.0 g per day is needed to achieve a good health effect.

Currently, there are a large number of stachyose-containing powdered drinks on the market, as well as a small number of oral solutions and fruit drinks. Due to their high safety, most of these products are suitable for a wide range of people, and can all promote the growth and proliferation of beneficial bacteria and improve intestinal function. Some functional products have a reasonable ingredient ratio, and the synergistic effect of multiple functional oligosaccharides is used to improve the utilization rate of oligosaccharides, making the effect better than that of products with a single type of oligosaccharide added. Table 1 shows some of the xylooligosaccharide-related products manufactured by domestic manufacturers and the possible effects.

4 Conclusion

With the advancement of modern technology and the improvement of people's level of awareness, people's consumption is gradually shifting towards healthy foods and functional foods. Some developed countries in Europe have developed as many as 400 to 500 types of multifunctional sugars. Functional sugars in China started relatively late, but their development and application have attracted the attention of many scholars in the country. As a new type of functional oligosaccharide, xylooligosaccharide is widely used in the food industry due to its low dosage and high safety. Many scholars have proved through experiments that xylooligosaccharide has the effects of detoxification and treatment of intestinal-related diseases. Due to individual differences in physique, the effects of a single functional sugar can vary, so the combined use of functional oligosaccharides has become a highly effective ingredient in foods that is widely recognized by companies. The best results are achieved through the appropriate combination and application. It is believed that natural, highly effective and safe functional oligosaccharide products, represented by stachyose, will have broad development prospects.

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