Removal of Astringency In Sugar: Bettering Alternative Sweetener Taste

Sugar substitutes offer a wide range of benefits, as they replicate the effect of sugar in taste but have few or no calories. Sugar consumption has been associated with lower food quality, increased energy intake, and the prevalence of obesity. However, a high level of sugar substitution is associated with a higher intensity of astringent flavor, including metallic flavor, bitter aftertaste, and sharp odor. The occurrence of these undesirable characteristics due to sugar substitution impacts the consumer acceptance of the food product. In this article, we stated a few technologies and ingredient-based approaches for the removal of astringency in sugar and after-effects triggered by sugar substitutes.

Astringency associated with Sugar Substitutes

Sugar substitutes have been around for over a century. However, there has been an explosive increase in their consumption since the 2000s. A high sweetness intensity characterizes most sugar substitutes in pure form and is non-calorific; hence, they are used by food manufacturers to limit sugar. They can be classified into three categories: semi-synthetic (e.g., lactitol, maltitol, xylitol), synthetic (e.g., aspartame, acesulfame K, saccharinate, cyclamate), and natural sweeteners (e.g., thaumatin, curculin, steviol glycosides).

Sugar substitute improves the flavor of foods or beverages. However, some may leave unpleasant bitterness, astringency, and aftertaste when consuming products containing such sugar substitutes. The flavor can be distinctly disagreeable for some individuals, meaning they may need to choose a different product to achieve their caloric goals. When someone receives extra stimulation from their sugar receptors, they may limit their ability to accept complex flavors in healthy foods. It is not uncommon to see people rejecting fruits and vegetables because they frequently use artificial sweeteners to improve the flavor of their foods.

An approach to effectively modulate the sugar substitutes’ temporal profiles is the “Sweetness Modulators.” These modulators use different mechanisms to resemble or enhance the sweetness in the form of a natural flavor. They block astringency, lingering notes, and bitterness caused by high-intensity sweeteners. Some sweetness modulators bring high–intensity sweeteners closer to the taste of sugar by working as taste receptor that functions by physically binding to the sugar substitute.

Removal of Astringency in Sugar: Sweet Taste Modulators

Sweet taste modulators dominate the market, with a market size of around 1.74 USD Billion in 2021. The sweetness market is expected to grow by 9.13% in the coming years.

The demand for sweetness modulators has been rising significantly owing to the manufacturing of nutritionally balanced products while maintaining flavor quality. Sweet taste modulators are becoming increasingly popular among fitness enthusiasts. It’s because they are in a range of sports and energy drinks. Growing consumer awareness of diseases such as obesity and diabetes fueling the taste modulator industry’s rise as they help regulate the individual’s sugar intake.

However, stringent government regulations and adverse health effects associated with sweetness modulators are expected to slow the growth of this market to some degree in the near future.

Removal of Astringency in Sugar: Solutions

For a quiet time, it was believed that the astringent taste of high-intensity sweeteners was due to impurities (specifically, o-toluene sulphonamide, a by-product produced during their synthesis) in the stimulus. However, further research has shown that excessive tastes are a genuine property of refined saccharin salts.

Given the wide range of bitter molecules and the genetic variation among individuals in their response to different bitter compounds, it is probable that the transmission of bitter taste encompasses several mechanisms. An important mechanism is proposed to block potassium flow outwards by substances like the powerful bitter compound denatonium.

Furthermore, five significant ways have been identified through which the lingering effect of sugar substitutes can be reduced or eliminated. The approaches are namely:

1. Sweetness enhancers
2. Cross adaptation
3. Bitter blockers
4. Viscosity modifiers
5. Aroma-induced sweetness enhancers

1) Sweetness Enhancers:

Sweet enhancer is a set of natural or chemical compounds that enhances the sweetener’s sweetness and HIS and eradicates hidden attributes, such as bitterness.

Sweet taste enhancers can increase sweetness perception by modulating T1R2/T1R3 receptor activity. New research focuses on identifying and developing unique flavor ingredients, including trilobatine, rebaudioside C, thaumatin, and mogrosides. These compounds act as positive allosteric modulators and boost taste sensation.

Positive allosteric modulators help reduce the required sweetener even by maintaining the desired taste.

2) Cross Adaptation

Researchers have identified many sweetener blends that help inhibit bitterness associated with individual sweeteners. A blend of sweeteners gives better sweetness than any constituent sweetener. This blend of sweeteners further reduces the off-taste associated with constituent sweeteners to a greater extent.

Blends of artificial sweeteners such as saccharin and cyclamate produce less of a bitter off-taste.

Each sweetener has a threshold limit for activating the bitter and sweet receptors. A combination of two sweeteners is prepared. One has a lower threshold limit for activating the bitter receptor and a lower threshold limit for activating the sweet receptor. This sweetener becomes the primary sweetener. Another sweetener, which has a comparatively higher threshold limit for activation of bitter taste, is used as a modifier when used in an amount lower than its threshold limit.

3) Bitter Blocker

Bitter binders are widely used in the food and pharmaceutical industries worldwide. These natural or chemical compounds help reduce or mask bitterness in a food product and can enhance its overall acceptability. Bitter blocker compounds block receptor sites, which prevents another bitter-causing compound from attaching sites and causing bitterness. This technology can achieve a 40-50% reduction in bitter taste.

Sodium acetate, sodium gluconate, adenosine3’, and 5’-monophosphate are generally believed to be safe and have shown signs of bitter blockage.

4) Viscosity Modifier

Viscosity is a physicochemical property of food; it is considered one of the most important parameters for maintaining quality and sensory aspects. A viscosity modifier reduces the diffusion of bitter compounds to control bitterness.

Thickening agents, such as guar gum and carbohydrates, can alter the viscosity to a greater extent.

These viscosity modifiers increase the viscosity of food; the increased viscosity lowers the diffusion rate. The reduced rate of diffusion decreases the release of bitter constituents.

The reduction in bitter constituents of food, in turn, reduces the interaction of bitter constituents with the taste buds and hence lowers the perception of bitterness.

Selection of an appropriate viscosity modifier is one of the most critical steps to achieving specific viscosity and diminishing aftertaste.

5) Aroma-induced Sweetness Enhancement

Aroma-induced sweetness Enhancement (AISE) is a cross-modal perceptual interaction repeatedly demonstrated in modal foods. The addition of aroma has increased sweetness intensity in many studies. These strategies could contribute to product reformulation with a lesser amount of sweetener.

The AISE approach was born from the hypothesis. It explained that by mere exposure to many instances of foods, humans learn to associate food aromas with the taste (intensity). The extent to which an aroma can enhance sweetness intensity depends on whether the pairing of stimuli is congruent. Only congruent sensory impressions can influence each other efficiently. Mimicking the aroma of sugar-rich versions of food would raise perceived sweetness by mere suggestion through the aroma. So, the removal of astringency in sugar is possible.

Exemplary Solutions

Conclusion

The astringent sensation and metallic flavor resulting from the high-level sugar substitution cause a lower sensory balance of the food products and beverages. Various unique modulation techniques represent a significant breakthrough in eliminating unpleasant sensations. It includes sweetness enhancers, cross-adaptation, bitter blockers, viscosity modifiers, and aroma-induced sweetness enhancers. These techniques are based on the principle of using the right amount of the sweetener, synergistic combinations, or physiological effect of aroma to ensure balanced delivery of sweetness or flavor to the consumers.

As food manufacturers focus on developing sugar alternatives, the taste will likely play an essential role in the acceptance of the food product. The demand for sugar substitutes without the lingering taste will impact their usage over the next few years. Thus, the removal of the astringency of sugar will be achievable.

Erythritol is known to improve mouthfeel and mask unwanted aftertaste such as astringency. Like many other sugar substitutes, allulose is noted for not leaving a weird, slightly astringent aftertaste.