Views: 11 Author: Golden Horizon (Chengdu) Technology Co., Ltd. Publish Time: 2020-06-30 Origin: Golden Horizon (Chengdu) Technology Co., Ltd.
Stevia has a great potential as a natural sweetener and sugar substitute product. However, this plant has a certain aftertaste, which will make some people feel uncomfortable. Therefore, scientists have studied the molecular mechanism behind the strong sweetness of stevia.
What makes stevia sweeter than ordinary sugar?
Researchers at Washington University in St. Louis determined the molecular structure of an enzyme called UGT76G1. UGT76G1 is a uridine diphosphate-dependent glucosyltransferase that catalyzes the addition of branched-chain glycosides to compounds in stevia, mainly two diterpenoids, rebaudioside A (RebA) and stevioside-making stevia The sweetness is 200 times that of ordinary sugar. On the contrary, without these branched glycosides, stevia will lose its sweet taste.
To study the molecular structure of UGT76G1, scientists used a method called X-ray crystallography. In this way, they crystallized the enzyme by combining the enzyme with RebA, thereby revealing a molecule and a large cavity containing growing branches. According to scientists, the large cavity of UGT76G1 makes it unique among glycosyltransferases-other glycosides in stevia add glycosides in a more linear manner. Understanding the structure of UGT76G1 helps scientists understand why Stevia has a high intensity sweetness, and more importantly, the rest.
Find sweetness without aftertaste
Although stevia is sweeter than sugar, it has a slight metallic aftertaste, according to the study's lead author Joseph Jess, a professor of biology at the School of Arts and Sciences similar to "licking aluminum foil." It is this aftertaste that discourages many consumers from using this natural sweetener.
Yates said: "This taste is specific to the main molecules in plant leaves, steviol glycosides and RebA." "It is their chemical structure that hits the taste receptors on the tongue, thus triggering the'sweetness', but They also hit other taste receptors, which triggered other flavors."
Although RebA and stevioside are the main ingredients that impart sweetness to stevia, they are not the only ingredients. Yates pointed out that there is evidence that stevia contains other trace amounts of rebaudioside, which do not have the same unpleasant aftertaste.
In addition, studying how UGT76G1 works can help scientists find other plants as sweet as stevia. Jez said: "There are also molecules in other plants that are not'Stevia', but can bring a strong sweet taste." "We can use the processing information of the Stevia plant to find these details."
Stevia is not the only sweetener with an unpleasant aftertaste. Artificial sweeteners (such as aspartame and saccharin) also have a clear aftertaste. However, unlike stevia, large amounts of these artificial sweeteners can have adverse health effects.
Benefits of stevia
Stevia is a natural sweetener that has been used in Central and South America for centuries. Stevia as a healthy substitute for sugar may be beneficial for people with type 2 diabetes. In addition to helping them reduce sugar, chemicals in plants can also help lower blood sugar levels by inducing the oxidation of adrenaline and producing the adrenal pigment hypoglycemic compound.
In addition to helping diabetes, stevia also has anti-inflammatory and even anti-cancer properties. This is due to the presence of chlorophyll and lutein in stevia. These not only help protect the body from harmful carcinogens, but also limit the types of cell growth that lead to tumor development.