Stevioside，as the world＇s third sugar source，is extracted from the leaves of stevia which belongs to dwarf shrub． So far China is the biggest stevioside producing and exporting country，and the stevioside yield is rising constantly． Its sweetness is 200 times more than sucrose． Therefore，stevioside is used as sugar substitutes． Stevioside，as a low calorific natural sweetener，is widely applied into beverage，high sugar content food，alcohol，aquatic products， dairy products，functional food，cigarette，medical and health and daily － use products． Stevioside itself also has the medical function，such as reduce blood pressure and blood lipid，improving wine quality，optimizing food quality，increasing the viable count，inhibiting the human glucose reaction，and adsorbing the flavor components of cigarette． Meanwhile，the cost of production is reduced as well． In this paper the situation of research and application of stevioside on food industry and other industries were summarized． Then，suggestions on the future development was proposed， such as the proportion of sugar substitute and how to get rid of the bitter taste．

New stevia amino acid sweeteners, stevia glycine ethyl ester (ST-GL) and stevia l-alanine methyl ester (ST-GL), were synthesised and characterised by IR, NMR ('H NMR and 3C NMR) and elemental analysis. The purity of the new sweeteners was determined by HPLC and their sensory properties were evaluated relative to sucrose in an agueous system, Furthermore, the stevia derivatives (ST-GL and ST-AL) were evaluated for their acute toxicity, melting point, solubility and heat stability, The novel sweeteners were stable in acidic, neutral or basic aqueous solutions maintained at 100 'C for 2 h. The sweetness intensity rate of the novel sweeteners was higher than sucrose, Stevia amino acid (ST-Gl and ST-Al) solutions had a clean sweetness taste without bitterness when compared to stevioside. The novel sweeteners can be utilised as non-caloric sweeteners in the production of low-calorie food.

Rebaudioside A is an important ingredient in steviosidemixture.Compare with the other ingredients， rebaudioside A has higher sweetness，more stable，more closermouthfeel to the natural sweeteners，and also keep other advantages of the original stevioside. Therefore，Rebaudioside A can be used as a kind of ideal natural sweetener products. Rebaudioside Aprovides zero calories and has a clean，sweet taste with no significant undesirable taste and widely used in a lot of functional food. This paper reviews the characteristics of rebaudioside A and its application in food. Several improved methods on its sweet taste characteristics and properties were also introduced

In recent years, with the continuous improvement of people's living standards. obesity, dental caries, diabetes, hyperlipidemia and other health problems have become more and more common. Sugar and sugar-sweetened foods give people the sweetess they need, but also bring a lot of energy intake, and the harm caused by excessive consumption is increasing. Thus, energy-fiee high-intensity sweeteners came into being. Among them, advantame, as the commercial artificial sweetener with the highest sweetness, not only has extremely high sweetness, but also has almost 0 metabolic calories in the human body, and at the same time has good safety. Therefore. Advantame has extremely wide application prospects. To this end, the synthesis technology of advantame and its intermediates was studied and explored. The main contents and conclusions are as follows:

Stevia, as a significant source of natural sweeteners, has garnered attention primarily for its main components, stevioside and Rebaudioside A, due to their low calorie content, high sweetness, and excellent safety profile. In recent years, emerging components like Rebaudioside D and Rebaudioside M have also sparked research interest. Although extensive studies have focused on the interaction between stevioside, RebaudiosideA, and the gut microbiota, the effects of other steviolglycoside sweeteners on gut microbial health remain unclear. This thesis aimed to explore the physiological effects of other steviol glycoside sweeteners, focusing on RebaudiosideB, RebaudiosideD, and RebaudiosideM, by examining their impact on the gut microbiota through in vitro simulated fermentation of mouse intestinal contents. The thesis also assessed potential applications based on preliminary results.

Advantame, with the chemical name N-[N- [3-(3-hydroxy-4-methoxyphenyl) propyl]-³-aspartyl]- L-phenylalanine 1-methyl ester, monohydrate, is an artificial sweetener made by a chemical reaction between vanillin and aspartame, which are both permitted as flavoring and food additives by the China National Food Safety Standard-Standards for Use of Food Additives (GB 2760). As an intense sweetener, advantame is approximately 903120 times sweeter than aspartame and approximately 14,000348,000 times sweeter than saccharose.

Negative consumer perception of stevia is often due to bitter aftertaste of major steviol glycoside (e.g., rebau. dioside (Reb) A). This study was to reduce bitter aftertaste of Reb A by blending with Reb D and M, which are known to have no bitter aftertaste, Taste profiles of various blends of the three glycosides were characterized using a trained panel (n = 6) and electronic tongue, It was found that there were significant differences (P {<} 0.05) in bitter taste and bitter taste at 90 s among the various blends, 'To evaluate food applications of the Reb blends, a consumer panel (n = 83) evaluated ice cream sweetened with the blends. The consumer acceptance indicated that blends of Reb A with Reb D and M can help decrease bitterness of stevia and ultimately increase liking score in high-sugar food applications such as ice cream, The findings suggest that blends of major and minor steviol glycosides may be one of the strategies to reduce bitter aftertaste of stevia and stevia-sweetened products.

Stevioside and rebaudioside A revealed anticancer effects against diversity of cancers, such as colon, breast and liver cancers. Rebaudioside A can trigger apoptosis in cancer cells via activation of caspase-dependent pathway In this study sodium alginate/poly(N-vinylpyrrolidone) as nano-carriers loaded with natural products rebau. dioside A (R) and/or stevioside (S) were assessed for anticancer activities. "The nanogel of structure R improved cytotoxicity against MCF-7, HepG2, HCT116 and A549 cancers by 60.29 %, 53.45 %, 72.86 % and 62.13 % correspondingly. Additionally, the nanogel of structure S improved cytotoxicity against MCF-7, HepG2, HCT116 and A549 cancers by 63.96 %, 53.41 %, 70.59 % and 52.88 %, respectively. Furthermore, the nanogel for mixture of R/S improved cytotoxicity against MCF-7, HepG2, HCT116 and A549 cancers by 78.86 %. 54.75 % 74.10 % and 56.53 % correspondingly. Also, cytotoxic activities of structures R, S and R/S and their nanogels exhibited low toxicity on VERO cells with IGso= 30.90-46.50 u and high selectivity against cancer cells Moreover, /'S (nanogel), R (nanogel) and S (nanogel) demonstrated the uppermost binding affinities with DNA at reduced ICso values of 31.50, 32.60. and 33.90 uy, respectively, In addition, they inhibited Topo-l activity with remarkably low ICso value of 0.95, 1.00, and 1.10 uM, respectively.