Effects of High-Fructose Corn Syrup on Perception and Release of

Chapter 17

Effects of High-Fructose Corn Syrup on Perception and Release of Flavors in Soft Drinks 1,3

Downloaded by UNIV OF QUEENSLAND on October 30, 2015 | http://pubs.acs.org Publication Date: November 11, 2003 | doi: 10.1021/bk-2003-0867.ch017

Thomas N. Asquith , and Robert L . Swaine, Jr.

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Asquith Flavor Systems, Cincinnati,OH,45231 Proter & Gamble Company, 6210 Center Hill Avenue, Cincinnati,OH45224 Current Address: Brown-Forman Distillary Company, 850 Dixie Highway, Louisville,KY40210 2

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Small changes in the amount of carbohydrate sweetener (Brix) can totally change the sensory character of a soft drink. Are the sensory effects caused by changes in release and/or perception of flavor? Model soft drinks were prepared that differed by 1 g of high fructose corn syrup per 100 g of beverage. The acid/brix ratio, amount of flavor and other ingredients were constant. The composition of head-space and breath were analyzed by APCI-MS. Replicate samples were rated by sensory panels for both aroma and flavor. The sensory ratings for changes in overall flavor and sweetness were larger than for changes in aroma. The composition of headspace and breath were changed by Brix. We concluded that Brix had more impact on flavor perception than on flavor release.

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© 2004 American Chemical Society

In Challenges in Taste Chemistry and Biology; Hofmann, T., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2003.


255 The amount of sugar (Brix) in juices and soft drinks has a major impact on consumer ratings for flavor. A difference of only one Brix (about 1% w/w) can significantly change the flavor of beverages. The cause for this flavor change is not fully understood. Possible explanations are changes in flavor perception and/or flavor release. Brix does affect the perception (1,2) and the release of flavor volatiles (3, 4, 5). However these studies reported the effects of large changes in Brix on flavor. Companies typically make small changes in Brix when developing new formulas. Yet flavorists must still adjust flavor composition to compensate for changes in Brix. Often this work relies on repetitive cycles of formulation and sensory evaluations. Understanding the impact of formulation changes on flavor systems should reduce development time and expense. Our experiments assessed the impact of small changes in Brix on perception and release of flavor. The experiments were done as part of a product development project to launch new varieties of juice products on accelerated timelines.

Materials and Methods

Sensory Evaluations Panelists were prescreened for ability to recognize and distinguish between basic tastes and aromas. They were also tested for ability to rank order the intensities of tastes and aromas on a nine point scale. Panelists also regularly consumed juice products. Samples were rated by thirty to fifty panelists for overall flavor intensity, sweetness, tartness, uncharacteristic flavor, aftertaste and overall liking. The rating scales ranged from 1 = low intensity to 9 = high intensity. Panelists were instructed to evaluate first for aroma and then for flavor.

Instrument and Operating Conditions Spectra were collected using a Micromass ZMD under conditions for atmospheric pressure chemical ionization (APCI). For headspace analyses the capillary flow rate was 2 ml/min with a desolvation gas flow rate of about 600 l/h. Capillary voltage was 4.50 kV, extractor voltage was 3.0 V, Rf lens was 0.3, source block temperature and desolvation gas temperatures were 50°C. The transfer line was a fused silica capillary (0.53 mm ID) encased in a copper line, which was kept at 120°C. Individual flavor components were analyzed by total ion current to verify major ions and relative purity. Ionization efficiency of



256 compounds depended on cone voltage values. Therefore each compound was analyzed as single ions (SJM-mode) to determine optimal cone voltages for maximum ionization efficiency (Table 1). Cone voltage values were generally higher for breath analysis than for headspace analysis. Note that mass resolution of the Micromass ZMD was too small to distinguish between the common terpenes in orange juice. Although method development was done with limonene and linalool the experimental values were reported as generic "terpenes". For actual analyses of samples, identities were based on abundance and behavior relative to standards. Identities were not confirmed by spiking standards. Conditions for breath analyses were based on recommendations from Dr. R. Linforth (personal communication). The capillary flow rate was about 280 ml/min with a desolvation gas flow rate of about 710 l/h. The high flow required the 1 mm (ID) tip rather than the 1.6 mm (ID) tip. Other parameters remained the same. Flavor components were analyzed as single ions (SIMmode).

Headspace Analysis The basic method was adapted from (3). Fifty ml of sample was poured into a 100 ml Schott Botde and equilibrated at room temperature for at least two hours. Caps for the Schott bottles had holes of about 3 mm. At ten minute intervals, the capillary was inserted about two centimeters into the jar. Headspace was sampled for one minute. Each sample was analyzed with seven replications. Excel software was used to calculate values for average peak area, standard deviation and coefficient of variation.

Breath Analysis Fifty mL of beverage were poured into a plastic cup. The breath was sampled by exhalation through a plastic tube into a T-splitter (Swagelock), which was connected to the transferline. Representative baselines were established by monitoring the acetone (M H+ = 59) peak in breath during several exhalations. Then beverages were consumed by sipping through a straw. After each swallow, the released odorants were exhaled. No further standardization was performed. Each beverage was sampled twice. There were large variations in the absolute amounts of ion from breath to breath. However the relative amounts of ions are fairly constant breath to breath (6). Seven distinct breaths were chosen. Using values for ion 117 as the common denominator, the other ions were converted to ratios against ion 117.


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Table I: MH+ Values and Cone Voltages for Selected Compounds Compound Major Ion C V. HS C.V.NS 25 Acetone NA 59 Ethyl Butyrate 18 18 117 Ethyl Valerate 16 18 131 26 Benzaldehyde 24 107 Octanal 21 19 129 14 16 Methyl Anthranilate 151 22 Limonene 20 155

Samples The "fruit punch" base contained a blend of fruit flavors, gum arabic, colorants and sodium benzoate. The amount of high fructose corn syrup (HFCS) was adjusted such that samples contained 11, 12, 13 or 14 Brix HFCS. The amount of citric acid was adjusted such that there was a constant acid/Brix ratio of 0.011. The citrus base contained citrus oils supplemented with individual flavor compounds as well as sodium hexametaphosphate, colorants and potassium sorbate. The amount of high fructose corn syrup (HFCS) was adjusted such that samples contained 11, 12 or 13 Brix HFCS. The amount of citric acid was adjusted with Brix such that there was a constant acid/Brix ratio of0.03.

Results

Sensory Ratings for aroma intensity were essentially constant (Figure 1). In contrast ratings for flavor intensity, sweetness and hedonics increased as Brix increased. Sourness intensity tended to parallel sweetness but the percent change was less than for sweetness (data not shown).


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Relath

w c M c t

1.40 1.35 1.30 1.25 1.20 1.15 i.io : 1.05 1.00 0.95 0.90 -

m Δ

/ 1

•

X

i w

—ι

Brix

Figure 1. Effect of Brix on Sensory Attribute; • = aroma intensity, • = flavor intensity, A= sweetness intensity and X = overall liking

Volatile Analyses Method Precision: coefficient of variation values were less than 0.05 for ions 117, 129 and 131, and generally less than 0.10 for ions 107, 151 and 155. Day to day variation was less than 10% except for ion 155, which varied by 20%. Effect of HFCS on Headspace Composition: Values from the fruit punch product are shown in Figures 2 and 3. The amounts of ions 117, 129 and 131 changed by about 20% between 11 to 14 Brix (Figure 2). The amounts of ions 107, 151 and 155 changed by about 70% between 11 to 14 Brix (Figure 3). The standard deviation values were small enough to detect significant differences in headspace composition between products that differed by one Brix. Clearly there was a larger effect of Brix on ions 107, 151 and 155 than on the other ions. The amount of Brix did not change the amounts of ions 117, 129 and 155 in headspace of the citrus product (data not shown). In order to check if the composition varied due to different amounts of flavor in the products, average peak area values were converted to ratios using ethyl butyrate as the common denominator (Table II). The trends were similar to those in Figures 2 and 3.



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Figure 2: Effect ofBrix on Ions 117, 129 and 131

Brix 11 12 13 14

Table II: Ratios of Volatiles in Headspace 107/117 129/117 131/117 151/117 155/117 11.9 1.5 14.6 0.6 1.1 13.4 12.4 1.6 0.5 1.0 13.8 2.0 0.5 18.6 1.0 16.0 21.0 0.6 1.0 2.3



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Figure 3: Effect ofBrix on Ions 107, 151 and 155


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Effect of HFCS on Breath Composition: Average peak area values were converted to ratios using ethyl butyrate as the common denominator (Table III). Values for 129/117 and 131/117 were essentially unchanged, 107/117 was variable while 151/117 and 155/117 increased as Brix increased. The trends were similar to those in Table 2. Just as with headspace composition, there were few differences between 11 and 12 Brix. Interestingly there was relatively more ion 151, and less ion 155, in the breath than in the headspace. The relative decrease in ion 155 was previously observed when the compositions of headspace and breath were analyzed for citrus products (6).

Brix 11 12 13 14

Table III: Ratios of volatiles in breath. 107/117 129/117 131/117 151/117 13.6 0.3 1.6 3.5 12.6 0.4 3.0 1.1 11.4 0.4 4.0 1.7 0.4 5.4 15.5 1.4

155/117 3.4 3.4 4.0 4.9

Conclusions APCI-MS can provide accurate measurements of headspace composition. The measurements showed that a difference of one Brix can affect headspace composition. Terpenes and aromatic compounds were more affected than esters and short chain aldehydes. Our results contrasted with published work (3, 4, 5). This was possibly because we examined fairly low concentrations of sugars (about 10-15%) whereas others examined effects across a broader range (about 20-60%). Changes in headspace composition reflect changes in water structure and solute solubility (5, 4, 5). Solute solubility may be very different at lower concentrations of sugar. Flavor solubility in ethanol/water systems is complex because the physical chemical structure of ethanol/water mixtures changes as the relative amounts of the two solvents change (7). Flavor release can be enhanced or suppressed depending upon percent alcohol and nature of the solute. Interestingly the same effects on flavor release were generally observed in exhaled breath after drinking products. Therefore the basic principles of release were similar in both the bottle and in the mouth. The relative decrease of terpenes in the breath, versus in the headspace, is probably not related to Brix. We consistently detected this phenomenon in citrus products regardless of amount or type of sweetener (6). Loss of terpenes may result from dispersion of limonene into the saliva rather than less release into the vapor phase. Despite the changes in headspace composition, panelists had a stronger reaction to the sweetness than to changes in aroma. The dominance of taste over aroma when rating beverage attributes was consistent with other work (i, 2). This suggests that adjusting total sweetness can compensate for small


262 changes in Brix. Large changes in Brix may require targeted reformulation of flavor volatiles.


References 1. Nahon, D.; Koren, P.; Roozen, J.; Posthumus, M . J. Agric. Food Chem. 1998, 46, 4963-4968. 2. Davidson J.; Linforth R.; Hollowood T.; Taylor A. J. Agric. Food Chem., 1999, 47, 4336-4340. 3. Friel, E.; Linforth, R ; Taylor, A. Food Chem. 2000, 71, 309-317. 4. Voilley, Α.; Simatos, D.; Loncin, M . Lebensmitt. Wiss. Technol., 1977, 10, 45-49. 5. Roberts, D.; Elmore, J.; Langley, K.; Bakker, J. J. Agric. Food Chem., 1996, 44, 1321-1326. 6. Zehentbauer, G.; Asquith, T.; L i , J.-J. in Trends in Flavour Research; Editor Etievant, P., Elsevier Science, Amsterdam, 2003; in press. 7. Conner, J.; Paterson, Α.; Piggott, J. J. Sci. Food Agric., 1994, 66, 45-53.


Effects of High-Fructose Corn Syrup on Perception and Release of

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