GSG Deep Dive: How Glucosylated Steviol Glycosides Work in Formulation
From Enzymatic Modification to Taste, Stability, and Application
Steviol glycosides are widely used as high-intensity sweeteners, but their sensory characteristics can vary significantly depending on molecular structure.
For manufacturers developing reduced-sugar foods and beverages, the question is therefore not simply "Which stevia is the sweetest?"
A more useful question is:
How does the structure of a steviol glycoside affect its performance in a real formulation?
This is where Glucosylated Steviol Glycosides (GSG) become particularly interesting.
1. What Makes GSG Different?
GSG refers to steviol glycosides whose molecular structures have been modified by enzymatically adding glucose units.
The basic steviol glycoside structure contains a steviol backbone with glucose or other sugar residues attached at specific positions. Enzymatic glycosylation adds additional glucose residues to these carbohydrate portions.
This may sound like a small structural change.
From a formulation perspective, however, the position, number, and linkage of glucose residues can influence sweetness intensity and sensory characteristics.
That is the fundamental idea behind GSG technology.
2. Why Add Glucose to Steviol Glycosides?
One of the long-standing challenges with some steviol glycosides is their bitterness, astringency, and lingering aftertaste.
A 2016 review of steviol glycoside modifications identified enzymatic glycosylation as a promising approach because modifying the carbohydrate moieties can alter the taste characteristics of the resulting molecules.
Research has also demonstrated that enzymatically modified steviol glycosides can show reduced bitterness and improved organoleptic properties under specific experimental conditions.
This is important because GSG is not simply about increasing sweetness.
The objective is to modify the overall sensory behavior of the sweetener.
3. How Does Enzymatic Glycosylation Work?
At a simplified level, the process can be understood in three stages:
Steviol glycoside → enzymatic reaction → glucosylated steviol glycoside
An enzyme acts on the original steviol glycoside and transfers glucose residues from a donor substrate onto the molecule.
Different enzymes and reaction systems can produce different glycosylation patterns.
Scientific research has investigated several types of carbohydrate-active enzymes, including glycosyltransferases and glycoside hydrolase/transglycosylase systems. Different donor substrates and reaction pathways can therefore generate different modified steviol glycosides.
This is one reason why "GSG" should not automatically be treated as a single identical chemical composition.
The production route and resulting glycoside profile matter.
4. Molecular Structure Matters More Than the Headline Number
When comparing stevia products, buyers often start with:
·95%
·97%
·98%
·99%
But with GSG, the headline purity number does not tell the whole story.
The molecular structure of the glycosides can influence:
·sweetness onset
·sweetness intensity
·bitterness
·aftertaste
·sensory balance
·performance in different formulations
Recent research examining the dynamic sensory characteristics of several steviol glycosides found meaningful differences in sweetness and bitterness profiles, and linked some of these differences to the number and position of glucosyl groups.
This leads to an important formulation principle:
The best stevia ingredient is not necessarily the one with the highest purity number, but the one whose sensory profile fits the application.
5. GSG and Taste: Why Formulation Still Matters
It would be incorrect to say that GSG automatically tastes better in every food or beverage.
Taste perception depends on many variables, including:
·concentration
·pH
·flavor system
·acidulants
·minerals
·proteins
·other sweeteners
·processing conditions
·the specific GSG composition
Research has shown that enzymatic modification can improve the sensory properties of steviol glycosides, but the magnitude and character of the improvement depend on the specific molecular structures and experimental conditions.
Therefore, application testing remains essential.
For an ingredient manufacturer, this means supplying only a COA may not be enough for technically demanding customers.
Application guidance and sample testing can become equally important.
6. Where Can GSG Be Useful?
Because GSG is designed around sensory modification, it can be particularly interesting in products where the taste profile of conventional steviol glycosides becomes a formulation challenge.
Potential applications include:
Beverages
GSG can be evaluated in:
·carbonated soft drinks
·flavored water
·fruit beverages
·dairy beverages
·coffee-based drinks
·functional beverages
Dairy and Nutrition Products
Potential applications include:
·yogurt
·milk beverages
·protein drinks
·nutritional products
Food Products
GSG may also be evaluated in:
·confectionery
·sauces
·bakery products
·desserts
·reduced-sugar formulations
The actual suitability depends on the formulation, dosage, regulatory requirements, and target sensory profile.
7. GSG Is Not Simply "Reb A With More Sweetness"
This distinction is important for buyers.
Reb A, GSG, and Reb M are all steviol-glycoside-based sweeteners, but they represent different approaches to achieving desirable sweetness performance.
Reb A
A highly purified naturally occurring steviol glycoside commonly used as a benchmark stevia ingredient.
GSG
Uses enzymatic modification of steviol glycosides to alter their carbohydrate structure and sensory properties.
Reb M
A naturally occurring minor steviol glycoside with a different molecular structure and sensory profile, and which can also be produced through bioconversion routes.
So the decision is not simply:
"Which one has the highest sweetness?"
It is:
"Which molecular profile gives the best result in my formulation?"
8. What Should Buyers Ask a GSG Supplier?
When evaluating GSG from different suppliers, we recommend asking for more than the product name.
① What is the specification?
Ask:
·Total steviol glycosides?
·Specific glycoside profile?
·Dry basis or as-is?
② What is the glycoside composition?
This can help determine whether two products marketed under the same general GSG description are actually comparable.
③ What enzymatic modification approach is used?
The production route can influence the resulting glycoside profile.
④ What analytical method is used?
Different analytical methods can produce different interpretations of composition.
⑤ Is there batch-level COA and traceability?
For industrial applications, consistency between batches is critical.
⑥ Has the product been tested in the target application?
A sample test in the customer's actual formulation is often more informative than simply comparing specification sheets.
9. What Does This Mean for Food & Beverage Manufacturers?
For product developers, GSG should be viewed as a formulation tool, rather than simply another stevia specification.
The development process can be approached like this:
Step 1 - Define the sugar-reduction target
↓
Step 2 - Select candidate sweeteners
↓
Step 3 - Evaluate sweetness and taste
↓
Step 4 - Test in the actual formulation
↓
Step 5 - Optimize dosage and sweetener combination
↓
Step 6 - Confirm stability and production performance
This approach can be particularly useful when a product developer is trying to reduce sugar while maintaining a pleasant overall sensory profile.
10. Regulatory Perspective
GSG has also been evaluated from a food-safety perspective.
EFSA evaluated glucosylated steviol glycosides produced through enzymatic bioconversion and concluded that their metabolism was sufficiently similar to that of authorized steviol glycosides, with no safety concern identified under the assessed proposed uses and use levels.
The EFSA assessment also described GSG as steviol glycosides with additional glucose units introduced through enzymatic processes.
For commercial applications, however, manufacturers and buyers should always verify the regulatory status and specifications applicable to the specific GSG product, production method, market, and food category.
11. From Ingredient to Formulation Solution
The development of stevia technology is moving beyond simply asking:
"How pure is the stevia?"
The more important question is increasingly:
"How does the molecular structure perform in my formulation?"
This is why technologies such as enzymatic glycosylation have attracted continued research interest.
By modifying the carbohydrate portion of steviol glycosides, researchers and manufacturers can explore new combinations of sweetness, sensory characteristics, and application performance.
For food and beverage manufacturers, this creates more options when designing reduced-sugar products.
TangBaoBao GSG Series
At TangBaoBao, we focus not only on the purity of steviol glycosides, but also on how different stevia ingredients can be used in real formulations.
Our portfolio includes:
·RA Series
·GSG Series
·RM Series
GSG is one of our key product areas, supported by our experience in steviol glycoside processing and enzymatic modification.
For customers evaluating GSG for beverages, dairy products, functional foods, or other reduced-sugar applications, we can provide samples and technical information for formulation testing.
The right sweetener is not simply the one with the highest number on the specification sheet.
It is the one that works best in your product.
References
[1] Gerwig GJ, te Poele EM, Dijkhuizen L, Kamerling JP. Stevia Glycosides: Chemical and Enzymatic Modifications of Their Carbohydrate Moieties to Improve the Sweet-Tasting Quality. Advances in Carbohydrate Chemistry and Biochemistry, 2016, 73: 1–72. DOI: 10.1016/bs.accb.2016.05.001.
[2] Ye F, Yang R, Hua X, et al. Modification of steviol glycosides using α-amylase. LWT - Food Science and Technology, 2014, 57(1): 400–405. DOI: 10.1016/j.lwt.2013.12.045.
[3] Devlamynck T, te Poele EM, Quataert K, et al. Trans-α-glucosylation of stevioside by the mutant glucansucrase Gtf180-ΔN-Q1140E improves its taste profile. Food Chemistry, 2019, 272: 653–662. DOI: 10.1016/j.foodchem.2018.08.025.
