New Ways for Beverage Formulators to Reduce Bitterness and Balance Sourness

Transcription

1 New Ways for Beverage Formulators to Reduce Bitterness and Balance Sourness Presented by: ABSTRACT Are you interested in reducing the bitterness of stevia and erythritol in light soft drinks, of minerals in sport drinks or of caffeine in energy drinks? Or are you eventually looking for a new acidifier to optimise the balance of sweetness and sourness in natural beverages? This paper discloses new technologies based on simple ingredients aiming to help beverage formulators to develop drinks that are healthy, functional, natural, and that still taste good.

2 INTRODUCTION Getting the bad things out, getting the good things in! This is the shaking trend in the highly mature beverage market in the developed countries. Looking specifically at the non-alcoholic beverages segment which represents 70% of the global beverage market in volume, but only 30% in value, manufacturers are confronted with four key expectations of consumers (according to Leatherhead Food Research, 2010): - Healthiness: with growing obesity, diabetes and heart diseases, consumers want to take in fewer calories, less sugar and less sodium, but more vitamins, minerals and antioxidants. - Functionality: with the culture of performance, consumers look for drinks that can fulfil specific needs like a shot of energy when they feel tired or high ion supply when they are exercising. Even water shall no longer only hydrate the body or quench thirst, but also provide important nutrients to the human being. - Simplicity: with the globalisation of the economy, the surge of food contamination scandals and the growing complexity of labels, consumers have lost confidence in what they eat and drink. As more and more they cannot trace where foods, beverages or their ingredients have been produced, and sometimes cannot even understand what they contain, many consumers turn to products which sound more authentic, e.g. certified organic, claimed natural or appealing to their sense of nostalgia. Such products shall contain only few, simple and recognisable ingredients and obviously no artificial ones. - Sustainability: with the increasing environmental awareness, local sourcing of foodstuffs and ingredients (or fair trade when the former is not possible) and carbon footprint aspects of packaging and of its content get more consideration in consumers purchase decisions. The good thing is that these themes allow innovative beverage manufacturers to grow in saturated markets and to get a premium in spite of fierce competition by delivering additional benefits to consumers. However, these themes also create new challenges for the beverage formulators, from physical and microbiological stability to sensorial perception. The challenge is even greater when the task is not to create a new beverage from scratch, but to make a healthy, functional, simple or sustainable variant of a highly successful drink tasting as the original because taste perception is unique to every person. Jungbunzlauer, a responsible and sustainable producer of food ingredients made by fermentation of natural renewable carbohydrates, aims to help beverage formulators to make their beverages more natural, healthy and functional, but still tasting good. The reputation of Jungbunzlauer citric acid and sodium citrates as refreshing ph regulators has already been second to none for decades in the beverage industry. More recently our highly bioavailable calcium, magnesium and zinc salts have permitted producers of fruit juices and clear beverages to increase healthiness and add functionality. Our potassium salts also meet this target according to the new European Health Claims regulation (more information available on request). New as well is the contribution of ERYLITE (Jungbunzlauer erythritol), a zero calorie naturally derived bulk alternative to sugar, to make healthier near water drinks. This paper now introduces gluconic acid and sodium gluconate as new ways to reduce bitterness and balance sourness in non-alcoholic beverages. February /12

3 WHAT ARE GLUCONIC ACID AND SODIUM GLUCONATE? Gluconic acid is an organic acid occurring naturally in low concentrations in fruits. Higher concentrations can be found in fermented beverages like wine and kombucha (up to 0.5%), and even higher ones in honey and royal jelly (up to 1%). Gluconic acid is the fruit acid with the closest kinship to glucose as it is nothing else than a molecule of glucose plus an atom of oxygen. In bee products an enzyme converts glucose into gluconic acid and in fermented drinks the job is done by microorganisms. Gluconic acid is commercially produced by fermentation of natural renewable carbohydrates and is typically available as a 50% solution in water. This is due to the fact that gluconic acid crystallises to glucono-delta-lactone (GdL) at higher concentrations. When GdL is dissolved in water, the reaction is reversed, resulting in a solution of gluconic acid. GdL is the standard dry form of gluconic acid as the latter cannot be obtained dry under normal crystallisation conditions. Sodium gluconate is the crystalline sodium salt of gluconic acid. REDUCING BITTERNESS WITH SODIUM GLUCONATE Inhibiting or masking bitterness has become a major challenge for beverage formulators with the increasing expectations of consumers relating to healthiness and functionality of beverages. In fact, many persons do not like bitter flavours and they like them even less where they do not expect them. Coffee drinkers know and expect the impact of caffeine on the taste of their preferred beverage, but the same coffee drinkers can find the same caffeine totally bitter in an energy drink as an energy drink is supposed to provide energy, it is not supposed to be bitter. Also sport drinks can taste bitter with their high load in minerals. And last but not least, Rebaudioside A ( x sugar sweetness) and erythritol (0.5x sugar sweetness) can both show a bitter aftertaste. Rebaudioside A is the most interesting component of Stevia Rebaudiana extracts and long awaited natural alternative to all artificial high intense sweeteners used in light beverages. Jungbunzlauer found that sodium gluconate can significantly reduce, and sometimes completely inhibit the bitterness of natural zero calorie sweeteners, minerals and caffeine. February /12

4 Bitterness reduction of natural zero calorie sweeteners In a sensory analysis performed according to ISO 5495, it was discovered that sodium gluconate reduces significantly the bitterness of stevia and erythritol without significant influence on sweetness (Fig. 1). Fig. 1: effect on sodium gluconate on bitterness and sweetness of stevia and erythritol solutions in water (paired comparison test, expert sensory panel, n = 17-21) sweetener sweetener dosage sodium gluconate optimal dosage effect of sodium gluconate on bitterness and sweetness stevia 0.05% % erythritol 10% * % significant reduction of bitterness no significant influence on sweetness significant reduction of bitterness no significant influence on sweetness * It shall be noted that such a concentration of erythritol is currently only relevant in Asia-Pacific where the use level of erythritol in beverages is partly unlimited. The USA have so far limited its use level in beverages to max. 3.5% and the EU has not yet permitted the use of erythritol in beverages. In further experiments, the ph of the aqueous stevia and erythritol solutions was lowered to a level of three with citric, malic and gluconic acids as well as combinations thereof in order to determine if the same or similar effects can be observed in media simulating a soft drink base (Fig. 2). It was shown that in such conditions, sodium gluconate can reduce strongly the bitterness of stevia and even inhibit completely the bitterness of erythritol. It was also discovered that sodium gluconate improves the balance between sweetness and sourness in such solutions. Fig. 2: effect of sodium gluconate on bitterness and sourness of aqueous stevia and erythritol solutions acidified to ph 3 using citric acid, malic acid, gluconic acid, citric acid + malic acid (80/20, 50/50, 20/80) and citric acid + gluconic acid (80/20, 50/50, 20/80) sweetener sweetener dosage sodium gluconate dosage effect of sodium gluconate on bitterness and sourness stevia 0.05% % stevia 0.05% % * erythritol 10% % erythritol 10% % ** reduction of bitterness increased sourness intensity strong reduction of bitterness increased sourness intensity strong reduction of bitterness decreased sourness intensity complete inhibition of bitterness decreased sourness intensity * At concentrations above 0.2% of sodium gluconate, salty notes become perceptible. ** At concentrations above % of sodium gluconate depending on the soft drink bases, salty notes become perceptible. February /12

5 Bitterness reduction of minerals Bitterness of minerals is a science by itself. Indeed it is difficult to predict if a combination of a given cation (the mineral) and anion (the carrier of the mineral) will taste bitter at a given percentage of the RDA of the said mineral, especially when the carrier is an organic acid. While chloride forms of calcium, magnesium and potassium always taste bitter at 15% RDA, and while the solubility in water of carbonate forms of those minerals is often too low to achieve a 15% RDA, there is no such rule for citrates, gluconates and lactates. While calcium lactate tastes bitter at 15% RDA, calcium gluconate and a calcium lactate gluconate do not taste bitter at the same RDA. On the contrary, while a potassium gluconate tastes bitter at 15% RDA, a potassium lactate does not at the same RDA. According to data extracted from Mintel GNPD, a database analysing new product launches, minerals added to new non-alcoholic cold beverages are mainly incorporated as chlorides, phosphates, carbonates and sulphates when inorganic salts are used, and lactates, citrates and gluconates when organic salts are used (Fig. 3). Fig. 3: most important mineral forms in non-alcoholic cold beverages (excluding water, dry beverage mixes and meal replacements) launched between 2008 and 2010 ranking potassium calcium magnesium zinc 1 citrate lactate carbonate gluconate 2 phosphate phosphate chloride sulphate 3 chloride chloride lactate lactate While the relative importance of calcium lactate as a single substance is by far the biggest in number of product launches (almost in three years), potassium in its three main forms was however more frequently incorporated into the categories of the analysis than calcium in its three main forms (approx launches with potassium vs. approx. 1'200 launches with calcium). This may be due to the fact that potassium salts are more frequently used for technological reasons than calcium salts that are mainly supposed to add functionality. The bitterness of 25 mineral salts was screened in aqueous solutions containing 15% of the RDA for potassium, calcium, magnesium (100% RDA for zinc). Carbonate forms of these minerals were not considered as their solubility in water is not sufficient to get to 15% RDA. The nine mineral salts written in italic in Fig. 3 were included in the screening test. All of them tasted bitter at 15% RDA for the mineral except zinc gluconate which did not even taste bitter at 100% RDA. A sensory analysis was then performed according to ISO 5495 on aqueous solutions of those bitter mineral salts (Fig. 4). It was discovered that sodium gluconate has a significant to very high significant effect for reducing the bitterness of the tested mineral salts. February /12

6 Fig. 4: effect of sodium gluconate for reducing the bitterness of aqueous solutions of mineral salts at a dosage corresponding to 15% of the RDA for potassium, calcium and magnesium, and 100% of the RDA for zinc (paired comparison test, expert sensory panel, n = 17-21) mineral salt mineral salt dosage sodium gluconate dosage effect of sodium gluconate for bitterness reduction potassium citrate 0.83% % very high significant potassium chloride 0.57% % high to very high significant calcium lactate 0.65% % high to very high significant calcium chloride * 0.33% % remarkable magnesium chloride 0.22% % very high significant magnesium lactate 0.47% % very high significant zinc sulphate 0.044% % significant to high significant zinc lactate 0.047% % high to very high significant * Results from the screening test Bitterness reduction of caffeine In a sensory analysis performed according to ISO 5495 (paired comparison test, expert sensory panel, n = 18), it was shown that % of sodium gluconate significantly reduce the bitterness of a 0.03% caffeine solution in water. BALANCING SOURNESS WITH GLUCONIC ACID Beverages containing gluconic acid naturally Gluconic acid is occurring naturally in fermented beverages like wine and kombucha. Kombucha is a fermented tea drink originating in Asia. A bunch of yeasts and bacteria converts sugar to alcohol, acetic acid, gluconic acid, lactic acid and other acids, whereby the alcohol is normally further converted to acetic acid and thus only present in trace amounts. Kombucha is getting momentum as an adult soft drink based on its claimed benefits on health, its lower sugar content and thus lower sweetness than mainstream soft drinks, as well as its naturalness. The most popular commercially available Kombucha brand is nowadays probably Carpe Diem from the energy drinks giant Red Bull GmbH. Red Bull GmbH had been quite visionary when it introduced Carpe Diem Kombucha in the Austrian market already fourteen years back, betting before others on the health and well-being trend. Carpe Diem has also jumped onto the simplicity train, claiming that it is 100% natural, and that it contains no colours, no preservatives and no artificial sweeteners. February /12

7 Bionade is another refreshment drink naturally containing gluconic acid which has rapidly gained popularity in Europe within the past decade. Contrary to Kombucha, Bionade contains only gluconic acid as the sourness provider, actually about 1%. In Bionade gluconic acid is produced by a bacterial fermentation of sugar and barley malt. Like Carpe Diem, Bionade contains no artificial colours, flavours, preservatives or sweeteners. But it has gone even further by using only ingredients of organic quality when available in sufficient quantities and thus received German and European organic seals. Bionade also addresses sustainability and authenticity concerns of consumers by sourcing important ingredients locally and, the icing on the cake, produced in a biosphere reserve recognised by UNESCO. And it appeals to their sense of nostalgia through its name, logo and bottle design. Not all beverage producers can maturate their new concepts so long and so perfectly as Bionade GmbH did, nor can all make gluconic acid in situ as soft drink manufacturers are normally rather blending specialists than fermentation experts. Those producers can get gluconic acid 50% solution in water as food grade from Jungbunzlauer. Sourness profile of gluconic acid Gluconic acid, like lactic acid, has a mild lingering sour taste. But, while lactic acid has a milky flavour, Jungbunzlauer found out that gluconic acid shows rather herbal notes (Fig. 5). Fig. 5: comparison of key features of gluconic acid with those of the four main organic acids (citric, malic, lactic and tartaric) and of the main inorganic acid (phosphoric) used in beverages gluconic citric malic lactic tartaric phosphoric natural occurrence commercial production fermentation fermentation chemical fermentation extraction chemical flavour effect mild, herbal bright, refreshing, fruity (citrus) mellow, fruity (apple) mild, milky brusque, dry very little sourness persistence long medium long long short short February /12

8 Owing to their fruity taste, citric and malic acids fit particularly well with fruit based flavours in carbonated soft drinks and flavoured still drinks. Due to its herbal notes gluconic acid, when being the sole acidifier, shall be more advisable in non-fruit flavoured carbonated soft drinks like cola, ginger, root or herbal, as well as iced tea. Several beverage recipes were developed with gluconic acid and tasted within Jungbunzlauer. A near to water drink with a delicate pear/mallow/melissa flavour (Fig. 6) had a ph of 3.1 and showed a well balanced sweetness and sourness as well as a clearly noticeable herbal flavour. Fig. 6: recipe of near to water drink ingredients % sugar 5.0 flavour base pear/mallow/melissa* 1.0 gluconic acid (50% solution) water ad * Wild, Germany: NW base A cola drink (Fig. 7) had a ph of 3.3 and showed a mild sourness, a typical sweetness and a round taste profile. Fig. 7: recipe of cola drink ingredients % sugar 10.0 flavour * 0.20 gluconic acid (50% solution) 1.75 water ad carbon dioxide ~7 g/l * Takasago, Germany: TEG Several tea beverages were also produced and tasted, all of them containing 5.0% sugar, 1.15% gluconic acid 50% solution, a natural tea flavour, and water to 100%. All drinks had a ph of 3.5 and showed a typical tea flavour (Fig. 8). February /12

9 Fig. 8: flavouring system and sensorial description of the tea beverages flavour % sensorial description black tea * 0.10 green tea ** 0.14 typical tea flavour pleasant sweetness and sourness typical green tea flavour slightly sour slightly sweet green tea with herbs *** 0.05 / 0.08 typical flavour of green tea and hints of herbs acidity not detectable chai with ginger and elderberry **** All flavours: Takasago, Germany 0.11 / 0.10 / 0.05 * vivid natural flavour, TEG ** natural flavour, TEG spicy flavour with essential oil notes slightly sour low sweetness *** natural flavour green tea TEG , natural flavour herbal drink TEG **** natural flavour chai TEG , natural flavour Ginger TEG , natural flavour elderberry TEG Gluconic acid combinations It has been shown that gluconic acid can be used as sole sourness provider in soft drinks and ready to drink teas. Combining acids may however make sense to optimise the balance between sweetness and sourness, to harmonise discordant flavour notes, to make the beverage microbiologically stable without using artificial preservatives, or to reduce costs. Combining gluconic and citric acids in the near to water drink with the pear/mallow/melissa flavour permitted for example to lower the ph from 3.1 to 2.9. This set the hurdle higher for microbial growth while keeping sweetness and sourness in a good balance, having still the clearly noticeable herbal flavour and adding a refreshing note (Fig. 9). Fig. 9: recipe of near to water drink ingredients % sugar 5.0 flavour base pear/mallow/melissa* 1.0 gluconic acid (50% solution) 0.22 citric acid 0.14 water ad * Wild, Germany: NW base February /12

10 In the bitterness reduction tests of 0.05% stevia solutions at ph 3 by sodium gluconate, the 50/50 blend of citric and gluconic acids also achieved a very good result, reaching the three preferred tastes out of the nine tested acids and combinations. Two preferred flavour profiles, namely citric acid and the 80/20 combination of citric and malic acids, were liked by the panellists because they resembled to commercially available light lemonades. Although they could not be used to the taste profile of the 50/50 blend of citric and gluconic acids as this is very new in beverages, the panellists particularly liked the balance between sweetness and sourness of this combination in presence of % sodium gluconate. Naturalness aspects Malic acid is quite often combined with citric acid, especially in light beverages containing artificial sweeteners, as its longer sourness persistence compared to citric acid allows masking the aftertaste of sucralose, aspartame, cyclamate, acesulfame K or saccharin. However, as stevia approval is broadening, as its cost shall come down with growing consumption and as sodium gluconate can significantly reduce its bitterness, the biggest hurdles are getting removed from the way to natural light beverages. But to reach the natural claim, beverage formulators then need to take out some more ingredients, thereof artificial colours, flavours and preservatives, but also acids produced by chemical reaction like malic acid, phosphoric acid and sometimes tartaric acid. From a sourness persistence point of view, phosphoric acid may be substituted by citric acid, but malic acid needs to be replaced by a lingering acid. The alternatives of choice are then logically fermented gluconic and lactic acids or combinations thereof, especially when artificial preservatives have to be taken out at the same time. Such a natural light soft drink has already been launched in France in Breizh Cola Stevia from the company Phare Ouest located in Britanny (Breizh in Breton language) is a natural, sugar reduced, ethnic cola. The combination of sugar and Rebaudioside A has permitted the manufacturer to achieve a 70% sugar reduction in a natural way. The traditionally used phosphoric acid in cola beverages has been replaced by a combination of gluconic, citric and lactic acids, claimed as a blend of organic acids obtained by fermentation. PepsiCo has a gone a similar, yet less advanced way, with Pepsi Raw in the UK (Pepsi Natural in the USA and Mexico). Like Breizh Cola Stevia, Pepsi Raw is claimed as a natural cola containing no artificial colours, preservatives, flavourings and sweeteners, but it is not yet sugar reduced. To get to the natural claim, PepsiCo replaced phosphoric acid therein by a combination of citric, tartaric and lactic acids. As tartaric acid sounds less familiar to consumers than citric and lactic acids which are automatically associated with citrus fruit and milk, the manufacturer explains on the Pepsi Raw website that these may sound scary, but all these acids are derived from natural sources. Tartaric acid, for example, is naturally occurring in grapes and we use it to add an edge to Raw s sweetness. Tartaric acid in fact has a short sourness persistence like phosphoric acid, but it can be quite expensive when extracted from wine lees, its traditional source in Europe and the Americas, and caution must be taken regarding naturalness of certain sources as novel production processes combining a fermentation step and a chemical reaction have been developed in Asia. February /12

11 HOW TO MAKE GLUCONATES RECOGNISABLE? As the closest derivative of glucose and made by fermentation on natural carbohydrates, gluconic acid is inherently simple and very close to nature. But like tartaric acid, and perhaps even more than tartaric, gluconates still suffer from a recognition problem even if a dry form of gluconic acid, glucono-delta-lactone, has already been used for decades in the dairy, bakery and meat industries. It is a fact that glucono-delta-lactone s name may be an issue for certain consumers and thus for certain food producers as it sounds long, complicated and chemical. Thereby it does not help to make ingredients lists on food packaging shorter and cleaner, even if it is as close to nature as citric acid or lactic acid. Another issue for certain food producers is that, after dissolution of GdL, its hydrolysis to gluconic acid takes a certain time. This feature makes GdL a unique acidifier and is the backbone of its use as a leavening agent in dough products and as a coagulant in cheese and tofu. But in soft drinks made by simple blending of ingredients, and thus with a high throughput, the stabilisation of the ph can take too long when using GdL. For these reasons Jungbunzlauer has developed a food grade version of gluconic acid 50% solution in water. Gluconic acid s name is already shorter, simpler and less chemical sounding than glucono-delta-lactone. The fact that its name contains the term acid also permits the consumer to assign it a function and to link it with other more familiar ingredients like citric acid or lactic acid. Yet the question remains: what is gluconic? Explaining what gluconic acid is allows addressing consumer s curiosity, sweeping away his eventual concerns and building awareness. PepsiCo does this with tartaric acid on the Pepsi Raw website. But as not every consumer is equipped with a smartphone or tablet PC yet, he may not be able to access the Pepsi Raw website while standing in front of the soft drinks shelf in the supermarket. PepsiCo has thus gone a step further with an ingredient of Pepsi Raw that is even less familiar to consumers than tartaric acid. PepsiCo explains directly on the packaging of the product that the stabiliser used therein, gum arabic, comes from the acacia tree and has put a drawing of an acacia tree next to the story. This elegant way to increase ingredient recognition can of course also be used for gluconates. A possible statement for gluconic acid on the beverage packaging could be: Gluconic acid is naturally found in honey. The gluconic acid herein is made by fermentation of glucose. This statement can be enhanced by a picture of honey or of a bee placed next to it. February /12

12 If gluconic acid and citric acid are used in combination, a possible variant may be: Gluconic acid is naturally found in honey, citric acid in lemon. The citric and gluconic acids herein are made by fermentation of sugars. When sodium gluconate is used, for example for bitterness reduction purposes, an additional sentence may be wise to make the link with gluconic acid, e.g. Sodium gluconate is a neutralised form of gluconic acid. Gluconic acid is naturally found in.... As GdL has a much longer history of use in the food industry than gluconic acid and sodium gluconate, its approval status is broader, especially outside of Europe and Japan. In some parts of the world it is thus not possible yet to use gluconic acid or sodium gluconate in beverages. This does however not mean that beverage formulators located in those countries are deprived of the benefits of those ingredients. Where only GdL is permitted, it can be used as an alternative to gluconic acid to balance sourness as it will anyway hydrolyse to gluconic acid once dissolved in the beverage recipe. If the ingredients blending process is too fast to end with a stable ph when using GdL, it may make sense to dissolve up to 45% GdL in warm water some hours before the production run to give it the time to hydrolyse to gluconic acid. GdL may also be used as an alternative to sodium gluconate to reduce bitterness, but, as it will also reduce the ph, the formulator will have to adjust the recipe by increasing the content of buffering agent like trisodium citrate. When GdL has to be used for approval reasons or is preferred for technological reasons, a possible introduction sentence for the statement on the label could be Glucono-delta-lactone is a dry form of gluconic acid. Gluconic acid is naturally found in.... CONCLUSION Getting the bad things out, getting the good things in! Gluconates can surely help to achieve this challenging objective in beverages. Produced by fermentation of sugars, they are close to nature and sustainable. Through their close kinship to glucose, they are also simple. By reducing the bitterness of Stevia, erythritol and important mineral salts, and by balancing sweetness and sourness remarkably, they permit beverage formulators to develop drinks that are healthy, functional, natural, and that still taste good. Gluconates, what else? Author: Raphaël Singer Product Manager Gluconates raphael.singer@jungbunzlauer.com February /12