58 March 2012 • The Manufacturing Confectioner ➤ F ood-grade organic acids have diverse functionality and fulfill several roles. Acids can enhance or extend flavors, decrease pH, preserve food and provide “pucker power.” In confections, supersour, flavor enhancement, flavor extension and nontraditional flavors are all growing trends. An acid’s job description is to extend or enhance tartness or sour perception in addi- tion to specific functions for gelled confec- tions. What would orange, cherry, straw- berry or lemon-lime be without acid as the star player? This paper will cover food-grade organic acids used in confections, their chemical pro- files, attributes, similarities, differences and alternative forms of the acid (liquid, powder, granular and encapsulated). A case study is presented as an opportunity to explore the application of acid blends for fruit flavors since they are found naturally in some fruits. FUNCTIONALITY OF ACIDS Taste Modification Acids are tart by nature. Flavor character- istics are due primarily to the acid’s molec- ular structure, solubility and the level of buffering in the food or beverage system. Hard candy, chews, gels and filled gels, licorice, fruit leathers or panned hard and soft confections all have different formula- tions. Use of acids in formulations that are sensitive to slight variations in pH, or the presence of components sensitive to acids, may require buffers to work with the acids to provide stability. Acids offer ranges in sourness, intensity and linger. These attrib- utes impact and help define flavors, balance sweetness and round out the total taste pro- file of the flavor in confections. In addition to taste modification, acids perform other functional activities in con- fections. These functional activities include setting pectin and establishing gel strength of gelatin gels by impacting pH of the con- fection. Sugar Inversion Another beneficial function of acid is its utilization to invert sugar. Acids used to control sugar inversion to make invert sugar can have dual roles depending on the candy and pH level. Acid in hard candy contain- ing high-fructose corn syrup and sucrose in conventional ratios also functions to cause low sugar inversion. Invert sugar helps to prevent recrystallization of sugar crystals. This helps to minimize grittiness or sandi- ness in hard candy. Inversion, when uncon- trolled by correct acid usage levels, can cause candy to become sticky. Sugar inver- sion is the hydrolysis of sugar (sucrose) and results in the component molecules glucose and fructose (sucrose → glucose + Acids in Confections Food-grade organic acids in confections offer ranges in sour- ness, intensity and linger; balance sweetness; and round out the taste profile; and perform other functions. Tammy Nash Jarrett Univar Tammy Nash Jarrett is employed at Univar in its Food Ingredients division in technical development. Prior to Univar she has worked at The NutraSweet Co., Chr. Hansen Lab- oratories and Silesia Flavors in quality assurance, research, product development and sales.
Transcript
58 March 2012 • The Manufacturing Confectioner
➤
Food-grade organic acids have diversefunctionality and fulfill several roles.
Acids can enhance or extend flavors,decrease pH, preserve food and provide“pucker power.” In confections, supersour,flavor enhancement, flavor extension andnontraditional flavors are all growing trends.An acid’s job description is to extend orenhance tartness or sour perception in addi-tion to specific functions for gelled confec-tions. What would orange, cherry, straw-berry or lemon-lime be without acid as thestar player?This paper will cover food-grade organic
acids used in confections, their chemical pro-files, attributes, similarities, differences andalternative forms of the acid (liquid, powder,granular and encapsulated). A case study ispresented as an opportunity to explore theapplication of acid blends for fruit flavorssince they are found naturally in some fruits.
FUNCTIONALITY OF ACIDS
Taste Modification
Acids are tart by nature. Flavor character-istics are due primarily to the acid’s molec-ular structure, solubility and the level ofbuffering in the food or beverage system.Hard candy, chews, gels and filled gels,licorice, fruit leathers or panned hard andsoft confections all have different formula-tions. Use of acids in formulations that are
sensitive to slight variations in pH, or thepresence of components sensitive to acids,may require buffers to work with the acidsto provide stability. Acids offer ranges insourness, intensity and linger. These attrib-utes impact and help define flavors, balancesweetness and round out the total taste pro-file of the flavor in confections.In addition to taste modification, acids
perform other functional activities in con-fections. These functional activities includesetting pectin and establishing gel strengthof gelatin gels by impacting pH of the con-fection.
Sugar Inversion
Another beneficial function of acid is itsutilization to invert sugar. Acids used tocontrol sugar inversion to make invert sugarcan have dual roles depending on the candyand pH level. Acid in hard candy contain-ing high-fructose corn syrup and sucrose inconventional ratios also functions to causelow sugar inversion. Invert sugar helps toprevent recrystallization of sugar crystals.This helps to minimize grittiness or sandi-ness in hard candy. Inversion, when uncon-trolled by correct acid usage levels, cancause candy to become sticky. Sugar inver-sion is the hydrolysis of sugar (sucrose)and results in the component moleculesglucose and fructose (sucrose → glucose +
Acids in ConfectionsFood-grade organic acids in confections offer ranges in sour-ness, intensity and linger; balance sweetness; and round outthe taste profile; and perform other functions.
Tammy Nash JarrettUnivar
Tammy Nash Jarrett isemployed at Univar inits Food Ingredientsdivision in technicaldevelopment. Prior toUnivar she has workedat The NutraSweetCo., Chr. Hansen Lab-oratories and SilesiaFlavors in qualityassurance, research,product developmentand sales.
fructose). The result is cold flow; thecandy becomes hygroscopic and loses itsform/structure (Figure 1).
Impact of pH in Gelled Confections
Gelled confections manufactured withstarch, gelatin or pectin hydrocolloids areimpacted by pH. It is important to maintainpH control and appropriate acidity levels ingelled confections to maintain stability. Lackof pH control may result in variations in thegel set of pectin. The set may occur too fastor too slow. For gelatin gels, acidity and pHimpact the strength of the gelatin set andmay degrade it. Too much acid impacts gel-atin gel strength and decreases firmness. Thegel strength of gelatin decreases at lowerpH levels independent of acid type. A pos-sible remedy to help gel strength in the pres-ence of acid is to add buffering salts orbuffered acids in the formulation to helpcontrol pH. Figure 2 illustrates the influenceof pH on gelatin gel strength. This informa-tion is important when using acid to flavorthe gelled candy as well as acidifying or for-tifying the candy.
Candy Fortification
Candy fortification represents anotherdiverse function for acid. Ascorbic acid, alsoknown as vitamin C, is used in gelledgummi-type vitamin confections and regu-lar gummi candy such as fruit snacks. Ascor-bic acid is an essential nutrient. Ascorbicacid is synthesized using cost-effective, nat-ural fermentation of carbohydrates. In for-mulating confections with ascorbic acid,dosage levels may need to be optimized todeliver targeted fortification levels due toheat, light and oxygen sensitivity of the acid.Another trend to consider with acids incandy applications is acid sanding. This isthe application of acids to the outer layer ofthe candy. Sanding the outer layer of gelledconfections has increased with the demandfor more sour taste.
Supersour Taste
Supersour taste appears to embrace themore sour the better theme. Surface sour-ness is meeting consumers’ demand formore sourness and manufacturers’ uti-lization of more acid. To accomplishincreased sourness, manufacturers aresanding the outer surface of candy withacid or acid-containing blends and avoid-ing degradation of the candy. The quality ofthe sanded candy depends on the steamtemperature for a sticky candy surface.Steam for the surface should be hot anddry for good adherence to the surface. Typ-ically, acid is added as part of a dry-mixblend for sanding. Blends may also includeencapsulated acids, buffering salts con-taining acids or lower-solubility acids likefumaric acid. A key factor to avoid productloss is proper time, temperature andhumidity when drying the candy.
Acids in Confections
A possible remedyto help gel strengthin the presence ofacid is to addbuffering salts orbuffered acids inthe formulation tohelp control pH.
Sugar inversion is induced by• low pH (high acid content)• high temperatures• high humidity
High inversion levels result in hygroscopicity:› Fructose is very hygroscopic› Cold flow
Figure 1
Acid’s Diverse Functionality
Figure 2
Gelatin Degradation
Acids offer many benefits through theirdiverse functionality and characteristics.Features and benefits of acids include nat-uralness and different acidity profiles aswell as their impact on flavors (Figure 3).Although scientists (i.e., sensory, product
developers and flavor chemists) considersourness from acids a basic taste categorywith varying intensity and duration of thesourness, the acids are not consideredequivalent. Figure 4 shows the similaritiesand differences of acids.
ACIDS IN CONFECTIONS
Acids in confections offer the various attrib-utes described earlier and have differentchemical structures and other analyticalvariations as points of differentiation. Fig-ure 5 shows the analytical attributes foracidulants used in confections.
Acids in Confections
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Acid Benefit
Citric acid Natural; impacts citrus flavors — refreshing; low cost in use
Lactic acid Natural; mild and lingering; good for creamy flavors with fruit notes;enhances mint and eucalyptus flavors
Fumaric acid More sourness than other acidulants; may help acid-coatedcandy due to low solubility
Malic acid Mellow, smooth, persistent sourness; enhances flavor profile;can mask some flavors; works well with high-intensity sweeteners
Figure 3
Acids — Features and Benefits
Similarities
Can modify flavorsAdjust pHModify sournessModify sweetness
Differences
Strenth/intensity, type of flavorCost in useSolubility and hygroscopic tendenciesSynthesis/structure/forms/molecular weight
(not typically in confections)Molar weight: 98.00Melting point (MP): 41°CSolubility: miscibleSource: mineralsTaste: sharp and blandForm: liquid (75%+)InorganicAcidity (pKa): 2.15, 7.20, 12.35
Phosphoric Acid H3PO4
D,L Malic Acid C4H6O5
Molar weight: 150.1 g mol-1
Melting point (MP): 206°C/403°FSolubility: 58% (wt/wt)Synthesis: natural (L+)Taste: strong/tartForm: solid, fine granularAcidity (pKa): 3.02, 4.34
Chemical structures and analytical char-acteristics of acids (e.g., form, solubility,molecular weight) impact the choice ofacid used for various profiles in confec-tions. The strength of the acid impacts theintensity of sourness observed in confec-tions. Acid strength is measured by disso-ciation— the measurement of release of thehydrogen ion. Hydrogen ion dissociationis represented by dissociation constants(Ka) and reported as Ka values. The val-ues are established experimentally andfound in technical literature.For example, high Ka values represent
strong acids. Some acids have more than onehydrogen ion to contribute and may havemore than one Ka value. Figure 6 is a chart ofcommon acids showing the number of hydro-gen ions available for dissociation.Acid choice for confections may be influ-
enced by storage conditions available tomanufacturers. Some acids are hygroscopicand will harden at inappropriate tempera-tures and humidity levels during storage.Ingredients that compact, become hard orlack flow properties have a negative impacton manufacturing. It is difficult to resolveissues if equipment or conditions are notavailable to grind or solubilize the ingredi-ent for processing. In some cases, liquid acidsolutions are available for manufacturing.One typical solution for confections is 50percent citric acid. Lactic acid is also avail-able as a solution (Figure 7).
Acid Profiles
As available acidulants at manufacturingsites and formulations evolve with newtrending candy types, consideration mustbe given to the acid’s sourness for thedesired sweetness and flavor profiles. Acidsourness can vary with each respective acid.Acids also have different sourness/tartnessintensities, taste perception and linger. Someorganic acids like those used in confectionsoffer quick sour sensation and dissipate
quickly. Examples would be citric acid andtartaric acid. Acids like fumaric, malic andlactic may linger longer depending on otherformulation parameters. These attributescould be helpful with sweeteners and fla-vors to balance the overall taste profile.Sweeteners and flavors should worktogether. Acid selection may help with bal-ancing the profile. For example, if a sweet-ener lingers longer in taste, organolepticallyit may be better for the flavor to extendwith the sweetener. In this situation it maybe more advantageous to use an acid witha longer linger to balance the profile. As acase in point, consider nonsucrose confec-tions with bulking agents and high-inten-sity sweeteners or consider candy formula-tions with alternative sweeteners havingdifferent sweetness onset and linger. It maybe favorable to use the traditional acid forthe flavor with an additional acid to com-plement the overall taste of the confection.In the example with the sweetener havinga longer linger, one may consider using
Acids in Confections
Acid choice forconfections may be influenced bystorage conditions.Some acids arehygroscopic andwill harden atinappropriatetemperatures andhumidity levelsduring storage.
(*form used in candy) Tartaric Hygroscopic Phosphoric–Inorganic Corrosive
Figure 7
Acids — Storage/Handling
Protons Acid1 Lactic
Acetic
2 FumaricMalicTartaric
3 CitricPhosphoric
Figure 6
Hydrogen Ions in Common Acids
Acids in Confections
Use of acids incandy should be
optimized to deliverflavor or broaden
the flavor profile inthe presence ofsweetness andcomplementing
target flavor.
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malic acid. It lingers longer and may carrythrough with the sweetener and flavor. At this point, we have covered different
aspects of acids from their profiles to per-formance. From an application point ofview, acids can help provide different per-ceptions in confections. Attributes such asmolecular weight, solubility and strength allhave a role in an acid’s profile in the appli-cation. The same role is demonstrated invarious fruits and fruit flavors.
ACIDS AND FRUIT FLAVORS
Consider the natural acids available in fruit.Some fruits naturally have more than oneacid present in the fruit’s profile.In formulating confections with fruit fla-
vors, evaluations should include the natu-rally occurring acids of the fruits repre-senting those respective flavors. Blends ofacids may characterize fruit flavors closerto the natural fruit. Some common fruitflavors with main and secondary acids areshown in Figure 8.Development of candy with fruit flavors
such as orange, cherry, and apple may bemore characteristic of the true fruit flavorif formulated with acids found in the nat-ural fruits. Fruit flavors described as “rawfruit,” “juicy,” “cooked” or “ripe” alsoimpact the choice of acid or acid blend tocharacterize the flavor as well as the inten-sity, linger and onset of sourness. As theflavor profile is defined, acid can help buildthe profile. The tart taste in the candy can
represent growth stages of the fruit suchas green, sharp or ripe for fruits like appleand strawberry. The different stages ofgrowth may have different concentrationsof the main and secondary acids andincrease as the fruit ripens. The flavor pro-files may also represent stages in process-ing which would allow for changes in acidor acid levels. Use of acids in candy shouldbe optimized to deliver flavor or broadenthe flavor profile in the presence of sweet-ness and complementing target flavor.Candy with unbalanced sweetness in thepresence of acids could result in it beingflat or overly sweet. It becomes moreimportant to select the proper acid basedon the intensity and duration of the acidfor the overall flavor.
Taste Profile Comparisons
Anhydrous citric acid serves as the stan-dard for relative intensity and duration andis set with an intensity of 100 (Figure 9).Lactic acid has a higher intensity and longertaste duration than citric acid. In compari-son, fumaric acid has much less intensity,but has longer taste duration. These char-acteristics are influenced by the acid’s lowsolubility and chemical structure.
Flavor Intensity
Orange flavor has higher flavor intensity inthe presence of citric acid followed by lac-tic acid (Figure 10). Observe cherry’shigher favor intensity with malic acid andlactic acid compared to citric acid. Straw-
The experimentallowed ademonstration ofthe traditional useof citric acid incitrus fruit flavorsand the potentialimprovement of thetotal taste profilewith the addition ofmalic acid to thecandy.
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berry flavor with lactic acid also shows anincreased flavor intensity in the data com-pared to citric acid. The data presentedsupports evaluating different acids in fla-vor profiles which may result in increasesin flavor perception and flavor intensity.
ACIDULANT CASE STUDY
Orange Hard CandyAcidulants in applications can be discussedin terms of case studies. In one case study,orange hard candy was commercially man-ufactured to demonstrate the impact of acidsand acid blends on flavor, sweetness andtartness perception. The experiment alloweda demonstration of the traditional use of cit-ric acid in citrus fruit flavors and explorationof the potential improvement of the totaltaste profile with the addition of malic acidto the candy. The orange hard candy sam-ples were wrapped in different color papersto aid in evaluations. For the tasting analy-sis, people were given six orange candy sam-ples with different treatment. Each candypiece was evaluated in the mouth for aperiod of time and descriptors were used todescribe the orange flavor character, sweet-ness and tartness. The tasting exercise with orange-
flavored hard candy provided an oppor-tunity to evaluate candy in the presenceof the traditional acidulant for orange fla-vor (citric acid) and citric acid blends. Theparticipants’ comments were varied withthe differences found with each acid treat-ment. However, the general consensus forthe most flavorful and balanced treatmentof the orange-flavored candy was the blendof citric and malic acid. It is important tonote the following observations regardingcharacteristics for malic acid:
• Malic acid provides a smoother flavorand flavor release
• Malic acid acts as a flavor blender• Malic acid provides more bufferingcapacity at low pH
These three attributes may account for theobservations with the samples describedin the case study.Throughout the discussions in this paper,
we have reviewed various acids used inconfections. We have reviewed the physi-cal, chemical and sensorial attributes fortypical acids found in fruits as well as prac-tical applications derived from evaluatingacids with a new perspective. Blends ofacids may bring more defined flavor pro-files in addition to possible cost- savings asa result of decreased usage levels.
CONCLUSION
In summary, we have learned that acidshave diverse features and functionality.Acids vary in molecular weight, pKa val-ues, forms (fine granular, granular, pow-der, and liquid), solubility and manufac-ture. Acids provide various functions inconfections: adjusting pH, impactingsucrose inversion, facilitating gelling prop-erties, determining firmness of gelatin gelsand modifying taste. Acids provide tastecharacteristics associated with tartness/sourintensity, solubility and flavor. Acid selec-tion in confections may facilitate balancebetween flavor, sweetness and tartness. Inreviewing the characteristic acids in fruitsand fruit flavors, combinations of acids mayprovide opportunities for flavors to char-acterize or enhance the true fruit taste per-ception in confections. n
