Introduction

Consumers' increasing interest in healthier lifestyles has led to a surge in demand for fortified, functional, sustainable, and better-for-you food and beverages.

However, these products often contain ingredients that can impart undesirable flavours and tastes, such as plant-based proteins, amino acids, vitamins, minerals, botanicals, caffeine, or high-intensity sweeteners.

Overcoming these challenges is crucial for flavourists and product developers who strive to offer enticing health benefits without compromising on taste.

In this blog post, we will dive into flavour masking, a strategic approach that involves using specific flavour molecules to effectively eliminate these unwanted off-notes.

Flavour masking challenges

Some of the ingredients that can cause unwanted tastes and flavours include the following:

Taste vs. olfactory receptors

The five basic tastes - sweet, sour, salty, bitter, and umami, are perceived through stimulation of receptor cells located in the taste buds that are located throughout the oral cavity (tongue, palate, upper throat).

The majority of taste buds are located on the tongue within the papillae. Each taste has distinct receptor pathways.

Sour and salty tastes are detected through ion channel receptors that perceive H+ and Na+ ions. Sweet, bitter, and umami tastes are mediated by G-protein complexes that initiate signal transduction cascades when target molecules are detected. All five tastes can be triggered by a wide variety of molecules.

Aromas, on the other hand, are perceived through stimulation of receptor cells in the olfactory epithelium located in the upper reaches of the nasal cavity.

These aroma compounds reach the olfactory epithelium either during inhalation (orthonasal olfaction) or during mastication (retronasal olfaction).

Aroma compounds bind to the receptors of olfactory neurons, activating a reaction cascade that triggers the olfactory nerve, signalling the brain. Different combinations of activated receptors are perceived as distinct aromas.

Taste and aroma have distinct receptor pathways, and they do not directly affect each other.

As a result, off-taste like bitterness can only be reduced by combining it with complimentary tastes through taste interaction, such as sweetness, saltiness, umami, and even fat. Similarly, carefully selected aroma compounds are necessary to counter off-flavours.

Therefore, various types of flavour maskers are essential to interact with either taste receptors or olfactory receptors in order to diminish off-tastes and off-flavours.

How flavour masking work

Flavour masking can be achieved through the utilisation of two distinct approaches: psychochemical and physical methods.

The goal of psychochemical masking is to deceive the brain into perceiving and identifying flavours, which helps to hide off-flavours, while physical masking alters the interaction between ingredients and taste receptors, to conceal off-tastes.

Bitterness masking

As mentioned in the previous chapter, bitterness can be reduced by combining it with complimentary tastes such as sweetness, saltiness, umami, and even fat.

🔸Sweetness molecules: Some bitterness maskers work by stimulating sweet taste receptors. They can be achieved using natural sweeteners like steviol glycosides or sweet molecules such as furaneol, which are commonly found in caramel/candy floss flavours, and tropical flavours like pineapple.

🔸Umami molecules, such as monosodium glutamate (MSG), are known for enhancing overall flavour and reducing the perception of bitterness. Using umami-rich ingredients like yeast extract, tomato and mushroom flavours, can effectively mask bitterness.

🔸Salt molecules, particularly sodium chloride (table salt) or other sodium salts, can also be used to mask bitterness in certain situations.

Acidity masking

Similarly to bitterness masking, sweetness molecules are used to reduce acidity perception.

High-intensity sweeteners & off-flavours masking

Some maskers work by leveraging potent aromatic compounds found in fruits and botanicals to effectively "distract" the brain.

These aroma compounds include vanillin and menthol and work effectively to cover off-flavours such as earthy, beany or cardboardy. 

There is not a one-size-fits-all solution

It's important to note that each product formulation creates its own unique flavour profile and requires different flavour masking solutions.

For example, factors such as the type of protein, its origin and terroir, extraction processes, and separation techniques all play a role. Additionally, the amount of each ingredient, how they interact, the process, and packaging all contribute to different off-flavours and off-tastes.

Flavourists use sensory evaluations and analytic methods in order to select the most effective molecules for the development of flavour maskers. These flavour maskers are specifically designed to neutralise or mask unpleasant tastes and flavours.

It is important to note that there is no one-size-fits-all solution, meaning that one flavour masker may not work well for all oat-based products, for example.

Creating effective flavour maskers is a time-consuming process that requires careful development. Therefore, flavour houses often have a ready-to-use flavour masking "toolbox" for every customer.

They may not have the resources and time to use advanced custom methods, such as sensory and analytic evaluations on each customer's project.

Flavour maskers can be labelled as natural flavouring, taking into account country-specific legislation that may impose certain limitations. However, maskers can be formulated to meet various requirements, such as Halal or vegan.

Ongoing research is being conducted to understand the science behind these molecular interactions, but the exact molecules to mask off-tastes and off-flavours are closely guarded by flavour houses.

Other options to consider

Unfortunately, flavour masking is not a fool proof solution. It can potentially mask some positive flavour notes and make a complex flavour profile appear flat.

Additionally, its effectiveness is not linear, which means that increasing the dosage may not necessarily enhance its masking properties; instead, it might introduce its own flavours or off-flavours.

This principle applies not only to flavour masking but to any flavouring. Therefore, it is recommended to use flavour masking in very small amounts.

As mentioned earlier, the complexity of your base might require multiple flavour masking solutions, which can make the process relatively time-consuming.

If it is your case, consider exploring alternative options beyond flavour masking to enhance your base.

Optimise the base

By modifying the quantity of ingredients that impact the off-tastes and off-flavours, can already enhance your base.

For instance, a small amount of sweetness, saltiness, or umami achieved through different ingredients can effectively mask bitterness, while sweetness can be utilised to decrease acidic perception.

Fats, as well as thickening ingredients such as gums, starches, and fibres, have the ability to minimise various off-flavours and off-tastes. This is due to their ability to coat the mouth and gradually release off-flavours and off-tastes from the food matrix.

Microencapsulation

Another option for addressing unwanted tastes and flavours is through microencapsulation. This process involves applying a protective coating to a specific ingredient. This method regulates the release of unwanted tastes and flavours effectively, thereby enhancing the overall taste profile of the finished product.

This technique can be applied to various components, including vitamins, minerals, amino acids, and botanicals like ashwagandha.

Flavour pairing

Another technique is to use flavour pairing to find complementary flavours.

Instead of trying to cover the tastes and flavours brough by plant-based protein, vitamins, minerals and botanicals, you could instead work with the base by finding the right flavour profile to blend, complement and balance the off-tastes and off-flavours.

For example, the natural bitterness of dark chocolate, cranberry, tea, coffee, kale, lime, grapefruit or mature parmesan can complement bitter off-notes, while orange, yuzu, mandarin or lemon may be good flavour choices for products with sour off-taste. 

For earthy and musty off-flavours, adding a nut flavour can be effective, such as opting for hazelnut, almond or peanut butter chocolate over a plain chocolate flavour. But you can also use savoury flavours like mushroom, beetroot, camembert, brie or even some bleu cheeses.

If the off-flavour is sulphury, a ripe raspberry, strawberry or tropical fruits flavours can add balance.

Leveraging the natural tastes of these ingredients can also help to create endless innovative sweet and savoury flavour offerings.

Conclusion

Through a deep understanding of sensory perception and molecular interactions, flavour masking plays a crucial role in the development of consumer-friendly products.

As the field of food science continues to advance, flavour masking becomes increasingly important in shaping the future of healthier, functional, and more enjoyable food options.

Instead of considering flavour masking solely as a way to cover up undesirable tastes and flavours at the end of the product development process, product developers should strategically explore tastes and flavours from the beginning.

This involves optimising the base, exploring flavour pairing, and gaining a thorough understanding of what causes unwanted flavours and tastes.

It should be noted that the exact science behind these molecular interactions is actively researched and closely guarded by each flavour house.

Link to related blogs you may enjoy

 🔶What You Need to Know Before Using Flavourings

🔶 What is a flavouring with modifying properties (FMP)?

🔶Finding Harmony in Chaos: The Art and Science of Flavour Pairing

🔶 Demystifying “Natural X Flavourings”: The Composition and Regulations Explained

References

Previous experience includes working at a flavour house, where I received comprehensive flavour trainings. 

IFST Masking flavours for plant proteins, 2020, https://doi.org/10.1002/fsat.3401_8.x 

Danielle R. Reeda,* , Toshiko Tanakab, and Amanda H. McDaniela, Diverse tastes: Genetics of sweet and bitter perception, Physiol Behav. 2006 June 30; 88(3): 215–226.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1698869/ 

Chauhan, Rohit. (2017). Taste Masking: A Unique Approach for Bitter Drugs. Journal of Stem Cell Biology and Transplantation. https://www.imedpub.com/articles/taste-masking-a-unique-approach-for-bitter-drugs.php?aid=20177 

Natcha Laokuldilok, Prodpran Thakeow, Phikunthong Kopermsub, Niramon Utama-ang, Optimisation of microencapsulation of turmeric extract for masking flavour,
Food Chemistry, Volume 194, 2016, Pages 695-704, https://doi.org/10.1016/j.foodchem.2015.07.150 

Gary Reineccius, Flavour chemistry and technology, second edition, 2006

Various flavour houses website, including Givaudan, Symrise and Mane.