Sucrose is the most common sweetener in the food industry, but a large amount of sucrose can lead to an increase in postprandial blood sugar, which can cause obesity and increase the risk of cardiovascular and cerebrovascular diseases; in view of the existence of these problems, people begin to Seeking new sweeteners to replace traditional sweeteners in the food industry.

Application of Steviol Glycosides in Food Industry

As a pure natural, low-calorie, high-sweet, high-safety substance known as the "third-generation healthy sugar source for humans", stevia can effectively replace traditional sweeteners as a healthy Sweeteners are used in the food industry. At present, steviol glycosides have been used in baking, beverages, dairy products, candy and other products.

1.Application of steviol glycosides in bakery products

Bakery products mainly refer to cakes, breads, snacks and other products. Sugar is an indispensable ingredient in the manufacture of bakery products. One of the most common is the application of sucrose in bakery products, its participation can improve the texture and taste of products.

However, the long-term consumption of large amounts of sucrose will significantly increase the risk of obesity, dental caries, and cardiovascular disease. As a new type of natural sweetener, stevioside has the characteristics of low calorie and high sweetness, which can effectively improve this situation.

In addition, steviol glycosides are also highly thermally stable. It can maintain its stability during the entire baking process, and can be heated to 200 °C without fermentation or browning during the cooking process. It maintains the flavor of the product and reduces the heat, making it possible to extend the shelf life of the product and broadening the application field of baking. For example, in the experiment of Karp et al., after replacing 20% of the sucrose in chocolate muffins with steviol glycosides, the cocoa flavor and sweet taste of the muffins were improved.

2.Application of steviol glycosides in beverages

Beverage products such as fruit juice drinks and carbonated drinks contain a large amount of sugar, and long-term drinking will lead to the continuous increase of obesity. Considering the existence of these adverse effects, many beverage companies have begun to add steviol glycosides as sweeteners in the beverage production process. For example, Rebaudioside A has been used in the production of beverages by Coca-Cola Company, the world's largest juice beverage distributor. Using stevia as a sweetener in the new generation of Coca-Cola's product, Coca-Cola, successfully achieved a low-calorie effect;

Nestlé also began to add stevia to their fruit drink Sanpellegrino to replace 40% of the sugar; PepsiCo also launched a stevia-added product, Qixi; in addition, some of the more common beverages currently on the market are Xiaoming, Nongfu Spring's tea Π, etc. Also began to use steviol glycosides to replace part of the sugar to reduce the sweetness of the product.

Although many beverage companies are starting to develop new products using steviol glycosides, there is a risk of losing consumers due to new formulations. At present, stevioside and rebaudioside A are the most widely used in the beverage market. Their addition can not only achieve the effect of low calorie, but also maintain the effect of sweetening. The most important thing is to effectively reduce the adverse effects of obesity and other adverse phenomena. probability of occurrence. For example, peach juice is prepared by mixing stevia (160mg/L) and sucrose (56g/L), which can reduce calories by 25% compared with a control sample containing 9% sucrose without affecting the sensory quality of the product .

Study on Modification of Steviol Glycosides

Although stevioside is a natural source of sweetener, and has the advantages of low calorie, high sweetness, and stable properties, its sweetness is still different from that of white sugar or sugar alcohols, with slight bitterness and poorer sweetness. The aftertaste, especially in hot-brewed products, will become more and more obvious. Improving the taste of steviol glycosides through modification methods is the direction of the joint efforts of sweetener companies. The main modification methods are chemical modification, enzymatic modification and microbial transformation.

1.Chemical modification

Chemical modification refers to changing the molecular structure of stevioside through chemical reactions, thereby changing its physicochemical properties and sensory qualities. The taste quality of stevia is mainly improved by changing the sugar group attached to the ligand. The chemical modification method has been rarely studied due to harsh reaction conditions, many synthesis steps, and safety reasons.

2.Enzymatic modification

The enzymatic modification method refers to the introduction of glucose groups into stevioside through enzymatic transglycosylation or hydrolysis to improve its taste. The enzymes used include cyclodextrin glucosyltransferase, β-galactosidase, dextrin glucanase, etc. The product prepared by this method is glucosyl steviol glycoside, which belongs to edible flavors. Steviol glycoside is modified by the above enzymatic method. Although the taste and quality have been improved, the relative sweetness will also be significantly reduced. Generally, the relative sweetness of the modified product is about 50-150 times that of white sugar.

3.Microbial transformation

Microbial transformation method refers to the transformation of stevioside by microbial metabolism. Most of the current research is to use enzymes in microorganisms to modify stevioside. Br'as H screened a fungus Gibberella fujikuroi, using Stv as The only carbon source medium induces the fungus to produce enzymes, with which the conversion of the Stv moiety to RA with a better taste is achieved.

The solid fermentation of Aspergillus aculeatus is carried out with bran medium, and the obtained enzyme liquid can convert all Stv and RC in steviol into steviol (SV) in the form of precipitation within 10 hours. RA with better taste and quality was effectively enriched.