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The secret of boosting freshness in juice beverages

Updated: Mar 5, 2021


Thomas Eidenberger,Jack Shi


Abstract:Freshness is one of the most important factors in determining consumer liking of a juice beverage and in making purchasing decisions, however it is often neglected by beverage manufacturers. Therefore, the manufacturers should pay more attention to the freshness of beverages, and improve it by means of flavor modulators. This article took sensory evaluation group blind tasting method to illustrate the how freshness can be perceived, freshness in beverages, creating freshness during flavor perception. Finally concluded that freshness is the result of a multi-sensory decision. As a result, the flavor modulator can be used to adjust the aroma, taste and other sensory factors of the beverage, so as to make it consistent with the previous freshness memory in consumers' brains, so as to improve the freshness of the beverage and enhance consumer liking for the overall sensory performance.

Key words:juice beverage; freshness; sensory; flavor; mouthfeel; flavor modulator; flavours; consumer liking


Success of non-alcoholic beverages on the market depends on a variety of factors. Although sensory quality (flavour) is a central factor, manufacturers tend to follow simple concepts to evaluate sensory quality: (1) Design of packaging, (2) Color & Appearance, (3) Smell & Taste, (4) Comparison with competitors.

Common sensory properties ascribed to beverages by consumers are “fresh” and “refreshing”. Not surprisingly the Health and Wellness Survey, conducted 2015 in 60 countries and involving 30.000 consumers, revealed that the most desirable food attribute is Freshness。[1]

Manufacturers neglect widely the importance of freshness as sensory property of finished goods. It might be speculated that from the manufacturer’s point of view freshness is introduced in products with the raw materials and by manufacturing conditions. It should be emphasized that beverages are perceived as fresh by consumers who are not aware about raw materials or manufacturing conditions.

The non-alcoholic beverage market is estimated to about 1.000 billion US $. Major trends in this segment are the consumer desire for beverages promoting health and well-being. Sugar reduction, functional ingredients, “all natural” and no added food additives are important to satisfy the desire for health, green/organic/sustainable and creating new experiences are important to satisfy the desire for well-being. Beverages following these trends are seldom rated top in freshness.

To overcome this discrepancy between the major trends in the beverage industry and products rated top in freshness has become a challenging task. Consequently many new beverages on the market flop and disappear quickly from the shelves or become niche products for very selected consumer groups. In our experience, neglecting the consumer driven expectation of freshness is the main reason for failing success.

Perception of Freshness is for beverages the most important sensory attribute to trigger high consumer liking and a buying decision[2]


1. How Freshness can be perceived


The "Oxford Languages and Google” provides a series of definitions and examples for the term freshness (languages.oup.com/google-dictionary-en/). From the various definitions provided it is obvious that freshness is used in a multitude of meanings. Although only few of the meanings are apparently relevant for beverages, other meanings may be transported by marketing and advertisement activities.

Freshness can be triggered on a semantic and symbolic level (i.e. presenting orange juice under an orange tree, freshly cut apple on juice package, presenting a beverage bottle within a group of young and healthy people celebrating or presenting youngsters sipping a bottle at the beach at sundown with strong wind)[3][4]

Freshness can be triggered on a perceptual level and is an important part of the sensory characteristics of a product (smell, taste, mouth-feeling, cognitive mechanisms and psychophysiological factors).

Semantic and perceptual information is processed concomitantly, inter-connected and each other influencing. The processing involves a continuous context-based alignment with information stored in our memory[5] At the end of the processing stands a decision whether or not freshness is perceived.


The first sensations are the color, the appearance (clear, cloudy, fizzy) and the temperature (ice in the glass, ice coated bottle). These alone can already trigger a sensory decision. In case of unblinded tasting (i.e branded can) our brain may also trigger a decision solely on basis of the brand, the design of the can/bottle or the prize in the shelves. [6][7][8]

The second set of sensations is related to the smell of a product, more precisely ortho-nasal sensations experienced while breathing in. The smell (in case of pleasantness “aroma”) is a very important decision-making part of sensations as it determines whether we ingest a beverage or not .[9][10]Interestingly, the recognition of a smell in our brain is more important than its pleasantness (i.e. the smell of tonic water is far from pleasant but quickly recognized).

When ingesting a beverage, contact with the tongue, the palate and the cheek’s mucosa creates a variety of sensations which bombard our brain .[11]Constant breathing while the beverage stays in the mouth, prompts retro-nasal sensations during breathing-out. Retro-nasal sensations affect the overall smell but also taste perception.[12][13][14]Evolutionary, the ortho- and retro-nasal “detection-system” is one of the most well preserved systems and functions anatomically very similar in Dinosaurs and humans. The explanation is that ortho- and retro-nasal sensations are extremely important to prevent swallowing of harmful food. While ortho-nasal sensations are acting as first barrier preventing ingestion, retro-nasal sensations act as last barrier preventing swallowing. [15]

Swallowing of a beverage triggers anatomically opening of the retro-nasal cavity which then is flooded with volatiles by breathing-out immediately after swallowing[16]

In a last step, flavor receptors in the throat induce after-taste sensations.


2. Freshness is a multi-sensory decision


From a sensory point of view perception of freshness is a multi-sensory decision process .[17] Freshness cannot be perceived by single taste receptors nor is it represented by a single stimulus of somatosensory neurons.

The freshness decision is a based on olfactory (smell) and gustatory (taste) signals sent via chemoreceptors (receptor cells), somatosensory signals sent by mechanoreceptors (mechanical stimuli) and nocireceptors (pain and temperature stimuli). Although apparently different stimuli are recognized by different cells/neurons and the information is sent to the brain via different nervous pathways, the brain coordinates all the information concomitantly and align it with previous experience to make to a decision.[18]

It is important to understand that perception of freshness cannot be created de-novo by sensations. Freshness is perceived as a consequence of associative stimuli processing that relates to previously experienced and memorized sensations and their meaning to us.[19]

Freshness perception is mandatory to generate a refreshing feeling that is associated positively in the memory with freshness. Fresh fruits are a good model to comprehend the perceived freshness and the refreshing feeling (i.e. apple, orange). Freshness is not necessarily associated with refreshing (i.e fresh bread, fresh fish) but in case of beverages, especially fruit based ones, refreshing feeling is in most cases the ultimate target to achieve. A refreshing feeling is connected to the positive experiences of alleviating unpleasant symptoms in the mouth and throat (dry mouth, thirst) as consequence of feeling hot, of exercise or of mental fatigue.

The freshness decision depends on the combination of sensory signals and their fit with our acquired perception of freshness. The clearer and the more easy recognizable a set of signals appears, the quicker and easier our brain can decide in favor of freshness perception. Ambiguity in a set of signals prevents a quick decision making process. A set of unclear and/or unrecognized sensory signals triggers uncertainty in our brain. This uncertainty is either interpreted as “not recognizable” or yields a decision telling us “similar to …. with following defects”. Both are decisions against freshness.

Quick and early recognition of a flavor is not only of major importance for the freshness decision. Our brain tends to stop further considerations once a decision is made (evolutionary useful feature as thinking costs a lot of energy). With other words, once a freshness decision is made, sensory attributes will no more followed up making failure responses or defect analysis much less probable than in cases where it took long time to recognize a flavor.

Freshness perception is an important contributor to “consumer hedonic preference”. A complicated and long lasting sensory decision making process to recognize a flavor triggers failure search and defect analysis (lower overall quality rating).


3. Freshness in beverages


The aroma (smell) is the first sensory attribute contributing to freshness. The freshness of a fruit based beverages is assessed by the perceived closeness of the smell to the perception of the original, unprocessed fruit. The closer the smell resembles the fresh fruit, the quicker our brain assigns it to the corresponding fresh fruit.

Table 2 provides an example how modification of lemon aroma triggers different freshness perception. Lemon juice was prepared from commercial lemon juice concentrate and water with a final sugar concentration of 5 g/100 ml. This lemon juice was assessed by smelling (5 blinded tasters) and compared to the same juice with added limonene/citral (0.25 mg each/100 ml) or with a flavour concentrate prepared from fresh lemons (Lemon Juice Volatiles Conc., Capua, Italy). As observed, the freshness perception based on smelling the aroma is strongly dependent on the quality of aroma and is directly related to the degree of liking.


Complex aromas in mixed fruit beverages can easily create ambiguity and disturb the decision making process. In such cases it should be considered to formulate the beverage with a quickly recognizable lead (dominant) aroma. Table 3 shows the effects when comparing a commercial “mixed red fruits juice” without and with added bilberry flavor to create a dominant aroma.


In an ideal scenario the smell triggers the decision making process and a freshness expectation is already created. It has to be emphasized that such an expectation needs confirmation by taste.

Taste is a major player in the freshness perception as it can confirm expected freshness or direct the brain by additional sensory attributes to the favored decision. Taste is part of the overall sensations in the mouth which include also the temperature, viscosity, sparkling properties and mechanical stimuli (shredded fruits).

Freshness is the consequence of a flavor perception (processed sensory attributes) if all sensory signals point in a balanced, coordinated and unambiguous way to the same stored image in our brain associated with freshness.

A refreshing feeling results from a freshness decision together with a mouth-feeling that is described as mouth-watering .[20] Mouth-watering is triggered by a balanced sweet/sour balance, a harmonic embedded taste signaling freshness and the absence of mouth-coating and lingering (fresh milk would be an example where freshness is perceived by smell and taste, but due to the lack of sweet/sour balance and mouth coating properties milk is usually not associated with refreshing).

4 . Creating Freshness during flavor perception

Aroma and taste are mainly responsible for a perceived freshness. Mouth-feeling contributes to the freshness perception and is of outmost importance for a refreshing feeling.

To connect the impact of mouth-feeling on the overall flavour perception, more recently a model for universal flavor factors has been described.[21] see Table 4.



In this model beverages are classified according to the mouth-feeling (contracting, coating, drying) and flavor intensity/complexity (low, high). Contracting mouthfeel is experienced as tactile “tingling” or “stinging” impression which is perceived as refreshing feeling. Acidity, saltiness, coldness (ice cubes) trigger a contracting mouth-feeling in the mouth. Refreshing is closely associated with a dominant mouth contracting and a low flavor intensity/complexity (equivalent to quick recognition).

Lemon beverages follow this categorization and are a prototype model for freshness/refreshing feeling. Pear juice can be perceived as fresh but is seldom refreshing. Low quality orange juice (pressing whole oranges at elevated temperature) is not perceived as fresh due to off-tastes contributed by skin and albedo (white skin) ingredients present in the juice.


5. Why beverages lack freshness


Lack of freshness can be caused by defects in a product. This case is excluded from further considerations below.

Frequently beverages lack freshness due to a mismatch of aroma and taste. Any mismatch creates ambiguity and prevents an early and clear flavor recognition which is important for freshness perception. Aroma creates an expectation and if the expectation is not confirmed by taste, ambiguity in the processing of sensory signal occurs.

Crude aroma and taste mismatches are nowadays seldom seen due to better flavours on the market and improved technology.

However even subtle mismatches cause ambiguity and delay in recognition but are much more difficult to correct. Especially improvement of taste is challenging due to the multitude of different sensations and their inter-dependence.

Following list shows frequent causes for subtle taste deficiencies:


Off-Notes (artificial, metallic, bitter, herbal)

Impaired sweet/sour balance

Too sweet or too sour

Time to onset and to peak intensity unbalanced

Mouth-feeling

Unexpectedly mouth-coating (thickener, high viscosity, aged or over-ripe fruits)

Weak mouth-watering (weak taste, lack of sourness)

Empty/void (lack of sugar)

Sweetness profile (especially sugar reduced/sugar free products)

Onset of sweetness too slow

Long lasting peak sweetness

Lingering sweetness

Impaired Time/Intensity sequence

Flavor, sweetness and acidity time/intensity curves are not congruent (not fitting to

the expected fruit flavor)


6. How freshness perception can be improved


EPC Natural Products has developed a range of products to improve the flavor perception and guide our brain to a freshness decision.

One example is Zestaroma 100LN (200 ppm) added to lemon juice with 5 % sugar. A comparative sensory evaluation showed that added Zestaroma 100LN accelerates the time to peak intensity of the flavor together with a quicker recognition of the flavor. The freshness perceived was rated substantially higher (4 against 2 on a five-point scale) in the sample with added Zestaroma 100LN (see Figure 1).



Figure 2 shows a sensory comparison for a commercial apple juice (7 % sugar) with added Zestaroma 100LN (200 ppm). The effect observed relates to an increase in the timed congruence of sweetness, acidity and flavor. The overall effect of adding Zestaroma 100LN is described as more balanced flavor, more matching natural (apple) and as better freshness perception.

Figure 3 shows a sensory comparison of orange juice samples prepared with a 50 % sugar reduction by adding Aspartame/Acesulfame-K without or with Zestaroma 100LN (200 ppm). In these samples, Zestaroma 100LN can reverse the changed perception of acidity and sweetness introduced by artificial high intensity sweeteners almost completely.

Figure 4 shows a comparative sensory evaluation of a sugar free carbonated orange/mango beverage with or without Zestaroma 100LN. In this example the Time Dominance Sensations for 3 attributes (acidity, sweetness and adequate mouth-feeling) was recorded. As seen addition of Zestaroma 100LN corrected the inadequate mouth-feeling and the inadequate time dominance of acidity/sweetness to yield a flavor perception rated as much more sugar-like sweets, improved sweet/acidic balance and improved mouth-feeling.


These examples show convincingly that the product range of Zestaroma is able to correct the flavor perception is various aspects to yield increased freshness perception and ultimately a refreshing feeling.


7. Conclusions

The market for non-alcoholic beverages exceeds the 1.000 billion US $ margin. Success in this market depends on the Freshness and Refreshing feeling associated with a beverage by consumers. Perception of Freshness is for beverages the most important sensory attribute to trigger high consumer liking and a buying decision.

From a sensory point of view Freshness is a multi-sensory decision mainly based on smell and taste signals processed in our brain. Quick and easy recognition of a flavor is the basis for freshness perception. Complicated flavor with ambiguous signals sent to the brain prevents quick recognition and finally a freshness perception.

Many products on the market suffer from more or less subtle deficiencies in smell and taste. Usually smell creates an expectation which needs confirmation by taste. Any mismatch between smell and taste disturbs the required quick recognition required for freshness and refreshing perception,

The product range of Zestaroma corrects various aspects of smell and taste deficiencies as well as mismatches yielding improved freshness perception and ultimately a refreshing feeling.



References

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