FN 453 Paired Research Project - College of Health and ... of acai berry juice addition to vanilla...

Effects of acai berry juice addition to vanilla ice cream on texture, viscosity, color, and consumer preference indicated

palatability of final product

FN 453 Paired Research Project Cheryl Werner and Susan Yao

11/22/2010

I. Abstract

Acai berries are a good source of antioxidants which contain free radicals to help prevent cancer and lessen the effects of diseases such as decrease the oxidative stress in Parkinson’s disease. Cancer, along with Cardiovascular Disease, consistently dominate as the top causes of American mortality. Because of this problem the addition of acai berry juice into an American favorite such as vanilla ice cream seems to be a great way to incorporate antioxidants into one’s diet. However, with the addition of the acai berry juice, keeping the sensory characteristics such as texture, appearance, and even an appealing taste is essential as to not turn consumers away from the product. Varying concentrations of Acai Berry Juice was added to French vanilla ice cream base and objective evaluation of texture, pH, and color was conducted along with subjective testing of random sample population to determine consumer preference. The addition of Acai Berry Juice reflected a statistically significant difference in pH and color, with the effects on texture remaining inconclusive. Furthermore, results indicate majority of consumers sampled ranked the addition of 175g acai berry juice to most preferred, though no statistical significance was able to be established.

II. Introduction In this experiment varied amounts of acai berry juice is added to vanilla ice cream to see

how the addition affect the texture, viscosity, color, and consumer preference of the final product. According to USDA reports, over 81% of American households purchased ice cream in a 6 months period (Davis and others 2010). Incorporating acai berry juice into such a widely purchased and consumed product will help increase the nutrition density value of ice cream. Research shows that indeed acai berries have health benefits such as a good source of antioxidants and phenol compounds. Results from research have even been proven to help fight developing cancers (Stoner and others 2010).

Research shows that acai berries are a very good source of antioxidants, which can help in fighting free radicals and could help prevent individuals from getting cancer or help fight off cancer as well as other diseases that contain free radicals and increase antioxidant enzyme activity. The phenol compounds shown in acai berries through research have also been shown to have other added health benefits. One of these benefits is that they act as a disinfectant. Acai oil is proven by research to have very high phenol content and is a very great alternative for foods and supplements. Another health benefit of acai berries is that they contain anti-inflammatory agents which can help one with inflammation common in many diseases (Jensen and others 2008).

One research article also shows that acai berries can act as an oxygen quenching agent in human cells. Oxidative stress is in many illnesses and diseases such as Parkinson’s and Alzheimer’s disease, which are neurological disorders (Hogan and others 2010). The antioxidant effects of acai berries as discussed above can also help in decreasing the antioxidant enzyme activity which can help in the treatment of the hippocampus, cerebral cortex, and cerebellum. Acai berry treatment of these muscles can help decrease the damage to the lipids and proteins in these tissues. Ice cream dominates as an American favorite when selecting sugary treats, adding acai berries to such product would provide a way to allow consumers to obtain the added health benefits from acai berries. It would allow consumers to have a very easy access to consume a food product they love and get added benefits of acai berries.

The main concern regarding this project lies in the appearance and palatability of the final product, both factors heavily contribute to consumer choice and preference of edible items. Objective testing will be utilized to analyze the texture, viscosity, and color of the final product, and a sensory panel evaluation will provide more concrete evidence regarding how consumers react to ice cream products which may appear less familiar than the “normal” flavors such as vanilla, chocolate, and strawberry. The main focus regarding consumer sensory panel lies in the sweetness of the final product. While low sugar content is one of the positive nutritional attributes of acai berries, it may prove to be the most prevalent reason for its failure to appeal to normalized American palate. The sensory panel evaluation will help gain insight on what ratio of acai berry juice to vanilla ice cream will prove to be most appealing to the average consumer.

For this experiment, our purpose was to see if the addition of acai berry juice in different amounts to vanilla ice cream will affect the physical texture, color, pH of the ice cream and how these factors will affect consumer preference and palatability of the final product. The independent variables are the addition of varying amounts of acai berry juice to vanilla ice cream by weights of 0g, 50g, 125g, and 175g. These varying amounts will give us a control in the experiment and then three other variable to compare to the control. The dependent variable is the texture, viscosity, color, and consumer palatability of final product samples. The first three variables are to be objective measured using appropriate food chemistry analysis instruments, and the last variable will be measured using randomly selected consumer sensory panelists. The objective measures that we will be testing are the Hunter Colorimeter, texture analyzer, and the pH. We hypothesize that the addition of acai berry juice will produce a change in texture, color, or pH of the vanilla ice cream with subsequent discernable variations in consumer preference. III. Method:

The recipe for vanilla ice cream base for all control and experimental samples is a standard French vanilla recipe extracted from a reputable James Beard organization affiliated gourmet website (simplyrecipes.com). The ice cream recipe has also been utilized previously for personal use and have yielded satisfactory results. The unaltered, original recipe for the ice cream base is as follows:

2 1/2 cups heavy cream 1 1/2 cups whole milk (separated into 1 cup and 1/2 cup) 2 vanilla beans, halved lengthwise 8 large egg yolks 3/4 cup sugar 1/4 teaspoon salt

The recipe yields 1.5 quarts (1419g). After adjusting the recipe to yield 0.528qt (500g) per sample and converting all measurements to metric: The final recipe for each sample (assuming each sample of vanilla base ice cream is 500g) is: 211.2 g heavy cream 127.0 g whole milk 0.7 vanilla bean 2.8 large egg yolks 59.4g sugar 0.4 g salt

Therefore, the total recipe for all 4 samples is: 844.8g heavy cream 507.8g whole milk 2.82 vanilla bean 11.27 large egg yolks 237.6g sugar 1.6g salt

Naturally, the measurements for vanilla bean and egg yolks will be rounded to the next highest whole number in order to facilitate experimental material purchase and handling.

Procedures of vanilla ice cream base preparation will not deviate from methods provided by original recipe instructions.

For accuracy and precision of data collection, the experiment will be repeated 3 times in entirety. Therefore, each sample will have 3 different versions, each made at a separate trial occasion, making a grand total of 12 samples. Each sample of each trial has different 3-digit code identification, with the information regarding the true identity of each sample privy only to the experimenters. All 3-digit code identification numbers were randomly generated using a random number generator with fields set at numerical values between 1-1000. Information is as follows:

Variable Type Sample ID Acai Berry Juice %

in sample Acai berry Juice

added (g)

Control 160, 515,645 0 0g

Experimental 1 549, 320, 352 10 50g

Experimental 2 814, 198, 685 25 125g

Experimental 3 455, 876, 514 35 175g

It should be noted here that in order to achieve the final standardized weight of 500g per sample, equivalent weight of vanilla ice cream base mixture will be taken out as that of acai berry juice added to the respective sample. Final weight distributions of all 4 variable types are as follows, note that final weight refers to each sample within the variable type:

Variable Type Sample Vanilla Ice Cream (g)

Acai Berry Juice (g)

Final Total Weight (g)

Control 160, 515,645 500 0 500

Experimental 1 549, 320, 352 450 50 500

Experimental 2 814, 198, 685 375 125 500

Experimental 3 455, 876, 514 325 175 500

Therefore, the final adjusted recipe for each sample of each trial is as follows:

Sample Heavy

Cream (g) Whole

Milk (g) Vanilla Bean

Egg Yolks

Sugar (g)

Salt (g)

Acai Berry Juice (g)

160, 515,645

211.2 127.0 0.7 2.8 59.4 0.4 0

549, 320, 352

190.1 114.3 0.63 2.52 53.46 0.36 50

814, 198, 685

158.4 95.25 0.53 2.1 44.55 0.3 125

455, 876, 514

137.28 82.55 0.46 1.82 38.61 0.26 175

In order to eliminate as much extraneous variables as possible, all samples will be prepared in the same procedural fashion: vanilla ice cream base will be made according to original prescribed recipe, and acai berry juice will be added at the same step for all samples (after ice cream base has been completely chilled in ice-water bath, immediately prior to freezing). Furthermore, all materials used in sample preparation will be as identical as possible, from the manufacture brand of ingredients of vanilla ice cream, the brand of acai berry juice, to the type/size/material of cookware (for example, the mesh sieve used to drain ice cream mixture will uniformly be made of metal). Temperature will be controlled in the fashion that ice cream mixture will be tested with the same standardized centigrade thermometer at previously appointed check-points of the preparation process. The acai berry juice’s temperature will be checked as well before addition, and the final temperature of the mixture pre and post freezing will be checked as well. Location of preparation will be kept uniform in order to eliminate discrepancies due to atmospheric temperature and pressure. Objective testing will be standardized in the sense that instruments will be standardized prior to initial testing and periodically standardized in between sample testing. Lastly, both objective and subjective testing process will be standardized in the sense that testing time, place, and supporting materials such as plates, spoons, and napkins, will be kept uniform in order to eliminate subjective testing discrepancies, and maintain objective testing standardization. Subjective testing will be further standardized in the event that the same individual who tasted samples 161, 549, 814, and 455 (Trial 1) was selected again to taste 515, 320, 198, and 876 (Trial 2), their subjective results will not confounded by their recognition or memory of previous samples’ ID coding. Objective testing selected are: Hunter Colorimeter for L, a, b, values of each sample, Texture Analyzer for the physical texture of the samples, and the pH of each sample (prior to freezing).

Sample Preparation:

1. Beat together yolk and half of the sugar in a medium bowl for a few minutes until mixture is smooth.

2. Heat cream, 2/3 of the milk, the other half of the sugar, vanilla bean scrapings, and salt in a medium sauce pan over medium heat. Heat until mixture starts to simmer and remove from heat, let stand at room temperature for approximately 10 minutes

3. set aside a large bowl of ice water bath

4. whisk 1/4 of slightly cooled cream mixture into yolk mixture slowly. Add another 1/4 of the cream mixture to the yolk mixture, then transfer the egg mixture back into the sauce pan containing the remainder of the cream mixture.

5. cook over medium high heat while constantly stirring, until mixture is thick enough to coat the back of the spoon, and reads at 82°C. Remove from heat and add the remaining 1/3 of milk slowly into the mixture.

6. strain mixture through mesh sieve into steel bowl set in water bath, stirring mixture until completely cool, add in appropriate amount of acai berry juice as dictated by sample identity.

7. pour mixture into ice cream maker and let stir for approximate 1 hour on medium speed.

8. transfer soft-serve into air tight container and let freeze for at least 2-3 hours

9. Objective Testing

a. Texture Analyzer: after removal of sample from freezer, scoop out equivalent amounts (~2g) into sample cup. Using procedures provided on Texture Analyzer, measure the necessary puncture force for cone probe to penetrate ice cream sample. Repeat 3 times each sample.

b. pH : This step is advised to be done before ice cream freezing. After ice cream batter is prepared, take equivalent amounts of batter (~2g) and set aside in sample cup. Equilibrate pH meter with provided solutions and read pH of each sample 3 times. Wait until pH index is stabilize for at least 5 seconds before recording each data point.

c. Colorimeter: after removal of sample from freezer, scoop out equivalent amounts (~2g) into sample cup, use procedures provided by Hunter Colorimeter and measure the L,a,b values for each sample 3 times.

10. Subjective Testing

a. 9-Pt. Hedonic Scale perceived sweetness test: randomly select population (6-8 consumers per trial) and ask each subject to taste all 4 samples in order of least acai berry juice added sample to most acai berry juice added sample. The subjects are to rank in the samples’ sweetness on a scale of 1-9 with 1 being “extremely sweet” and 9 being “ extremely sour”

b. Consumer Preference Test: the same consumers who just finished the 9-Pt. Hedonic Scale are then to rank the 4 samples they tasted in order of preference from 1-4 with 1 being most preferred and 4 being least preferred.

Sensory Evaluation Sample

Please taste ALL samples in front of you Please wait 15-30 seconds between tasting EACH sample

On the scale below, please rate each sample

160

549

814

455

Please rank samples in order of preference, 1 = like the most 4 = like the least 160 _______________ 814_____________________ 549________________ 455___________________

Extremely Sweet

Very Sweet

Moderately Sweet

Slightly Sweet

Neither Sweet Nor Sour

Slightly Sour

Moderately Sour

Very Sour

Extremely Sour

Extremely Sweet

Very Sweet

Moderately Sweet

Slightly Sweet


Slightly Sour

Moderately Sour

Very Sour

Extremely Sour

Extremely Sweet

Very Sweet

Moderately Sweet

Slightly Sweet


Slightly Sour

Moderately Sour

Very Sour

Extremely Sour

Extremely Sweet

Very Sweet

Moderately Sweet

Slightly Sweet


Slightly Sour

Moderately Sour

Very Sour

Extremely Sour

IV. Discussions

The effects of adding varying quantities (g) of Acai Berry Juice (ABJ) to French Vanilla Ice cream are measured using both objective and subjective methodology. The objective testing methods include (1) Texture Analyzer evaluation of Penetration Force(g) on finished frozen samples, (2) pH recordings of sample batters prior to freezing, and (3) Hunter Colorimeter measured L, a, b values for samples. The Subjective evaluation methodology includes (1) Sensory Panel Ranking of Samples on a 9-point Hedonic Scale based on subjectively detected sweetness levels, and (2) Sensory Panel Ranking of samples on a scale of 1-4 based on subjective sample preference, with 1 being most preferred and 4 being least preferred.

As Figures 1-3 shows, samples from all trials exhibit similar trends in color variance as concentration of ABJ increased. Generally, L values, which measures color value on a scale of 0-100 with 0 being the darkest (black) and 100 being the lightest (white), exhibits an inverse relationship with ABJ Concentration within a sample. a-values, which measures color hue, ranging from (-)a to (+)a, or green to red, respectively, exhibits a positive correlation with ABJ Concentration. Lastly, b-values, which measures chroma, and ranges from (-)b to (+)b, or blue to yellow, respectively, exhibits a negative correlation with ABJ concentration. For visual depiction of L,a,b scale, refer to Appendix 2. The general relationship between ABJ concentration and effect of ice cream product color can be summarized in that the ice cream color becomes darker as the addition of ABJ to stock French Vanilla Ice cream sample increases. For visual swatches of sample colors from all trials, refer to Appendix 1. Furthermore, as Table 2 and Figures 4-6 show, various sample types of each trial does not stray far from the calculated average L,a,b value, with the exception of the L-value of 125g ABJ addition, which shows a mean standard deviation of 1.78. Furthermore, upon comparison, each sample type exhibits statistically significant difference in color (p<0.05), as shown in Table 3. The only three outliers are the L-value comparison between 50g juice addition vs. 125g juice addition, L-value and a-value of 125g juice addition vs. 127g juice addition. Such errors may have arose from manual mishandling during measurement or raw data recording, or it may have be due to incomplete mixing during sample preparation, as each trial samples are manually operated, the comprehensiveness of juice to ice cream mixture is difficult to standardize. Overall, the results reflected from Hunter Colorimeter allows for the rejection of Null Hypothesis. Progressive variance in ABJ concentration within stock French Vanilla Ice Cream samples produces a statistically significant effect in final sample color.

Texture Analyses of ice cream sample of all trials are completed using a cone probe to measure necessary force (g) to puncture through ice cream. All ice cream samples are previously frozen for three consecutive days after preparation. Table 4 reflects the average observed puncture force for each sample type of each trial, and Table 5 exhibits the compiled puncture forces with respectively standard deviations. And lastly, Table 6 reflects statistical differences, if any, of ice cream texture as a function of ABJ addition. The data from the aforementioned tables are congruent with graphs shown in figures 7-11 in that there does not seem to be an observable correlation between ABJ concentration and ice cream samples’ texture. Furthermore, as Table 6 confirms, observed texture analyzer values for samples are not statistically significant from one another (p>0.05), with the exception of 50g juice addition vs. 125g juice addition. However, such

random outliers may simply be due to miscalculations, and/or error in data recording. Therefore, the null hypothesis stands in this case- as observed data reflects, ABJ concentration does not seem to have an effect on final ice cream texture. It must be noted here that several manual errors were made during this specific objective evaluation that may have negatively affected the data collection and subsequent conclusions. The samples of each trial, although frozen in the same freezer for the standardized three-day time period, were simultaneously transferred out of the freezer into room temperature. Since the texture analyzer measurement of the ice cream samples were not done in a systematic fashion (control samples first, 50g ABJ addition samples second, etc), any samples that were measured later have begun to melt and obviously, such results would not be accurate. Furthermore, since each sample underwent three random texture analysis, the location where the probe punctured the ice cream has drastic effects on the reported puncture force, and as the ice cream is melting as each sampling measurement is taking place, the third measurement of each sample of each trial would definitely be much less than the initial recording. Therefore the precision factor of this analysis is also compromised. Such issues may have completely skewed the observed results, however, until this experiment is repeated and data gathered once again, there is not enough evidence to reject the null hypothesis.

pH evaluation of each sample is reflected in Table 7 and 8, with Table 8 exhibiting mean standard deviations from the calculated average of each respective sample type. Also, as Figure 12 shows, as ABJ concentration increases, the average observed pH value decreases, with such trends observed throughout all three trials. Such observations are within expectations, as the French-Vanilla ice cream recipe calls for basic ingredients such as cream, milk, eggs, and sugar, while the ABJ exhibits a comparatively lower pH of approximately 5.7 (Schreckinger and others 2010). Therefore, the more ABJ is added to the stock ice cream sample, the more acidic the final product becomes, with the 175g ABJ addition samples holding a pH of approximately 5.8 + 0.01, a value is extremely close to the expected pH of pure ABJ. Lastly, Table 9 reflects that the pH variances between different sample types are statistically significant, except for the comparison between Control and 50g Juice addition samples. Such lack of statistical difference in average pH values is expected, as 50g ABJ addition reflected only a minute decrease in pH (Table 7). Perhaps 50g of ABJ is sub threshold in terms of ability to cause a statistically significant decrease in sample pH. Overall however, the results allows for the rejection of the null hypothesis- ABJ concentration, once above threshold concentration, produces a statistically significant change (decrease) in pH of the ice cream sample.

Subjective Evaluation of the ice cream samples in all three trials are carried out using randomly selected college students. The first test requires the subject to evaluate the samples on a scale of sweetness, with 1 being “extremely sweet” and 9 being “extremely sour”. The average score depicted in Table 10 was calculated by compiling all scores for each sample type and dividing by total number of participants (24). Subsequently, the average scores are plotted the dotted-scale shown in Figure 13. Each dash is equivalent to 1/10th of a point, and the “x” marks where the average scores fall on the 9-point Hedonic Scale. Table 10-11 also reflect that there is no major difference between average consumers perceived sweetness difference in all samples from Trials 1-3. This trend is reflected in Figure 13. As the sweetness rankings on the 9-point

Hedonic Scale for all four different sample types falls in the ranges of 3.6-3.9, or between moderately sweet to slightly sweet, respectively. Such data is congruent with the results reflected by the pH values of sample types. Although sourness and astringency increases with decreasing pH levels, no significant changes in perceived sweetness is found at pH ranges from 3-7 (Schiffman and others 2000). Since all ice cream samples, although exhibiting a statistically significant decrease in pH with increased concentration of ABJ, did not fall out of pH ranges from 3-7, it follows that consumers would be unlikely to detect sweetness level alterations.

The second subjective test requires the same participants to rank each sample (4) in order of preference with 1 being most preferred and 4 being least preferred. Figure 14 shows the percentage distribution of rankings. 175g ABJ addition samples are the overall most preferred (38%) and Control samples are least preferred (17%). A correlation calculation between rankings and level of sweetness reflects a strong inverse relationship (Table 13). However, such data is incongruent with the aforementioned subjective sweetness ranking results. Therefore, A chi-squared test is conducted to determine the statistical significance of Panelist ranking distribution. The resulted value shown in Table 14 reflects that the resulted ranking order of samples is randomly distributed rather than statistically significant. Therefore, the null hypothesis cannot be rejected- ABJ concentration did not affect subjective sensory evaluation both in terms of perceived sweetness and in terms of preference. It should be noted however, that perhaps with a larger population, statistical significance between consumer preferences can be established.

Overall, this experiment proved to be successful in terms of objective evaluation of ABJ concentration and its effect on ice cream pH and color. For future studies, several alterations should be made in order to more successfully conduct this research. Firstly, a larger population sample should be selected. This experiment’s sample population, although randomly selected, was too small and only covered college age students in a specific geographical location. Such discrepancies may have confounded sensory panel evaluation results. Secondly, as previously mentioned in Texture Analyzer discussion, sample should be extracted from the freezer at a need-to basis in order to battle the confounding factor of time and melting. Thirdly, consumer preference of ice cream is dependent on multiple factors other than sweetness; perhaps future studies can limit experimental variables so consumer preference rankings can be concluded to be dependent on a single variable.

This experiment reflects many intricacies behind ice cream manufacturing, and exposes many previously overlooked factors in the production of a successful consumer product. The texture, color, sweetness index, and many other variables all play a big part in ice cream product formulation, which all in turn, may translate to variance in consumer preference.

V. Results

Table 1 Average L,a,b Values for Trial 1, 2, and 3 Samples

Trial 1 Trial 2 Trial 3

Sample Type

L

a

b

L

a

b

L

a

b

Control 79.94 0.24 16.54 80.62 0.49 17.25 79.01 -0.56 16.53

50g Acai Juice Addition 59.75 1.58 9.14 59.87 1.90 9.16 59.52 1.25 8.66



Table 2 Compiled Average L,a,b, Values for varying Sample Types for All Trials as Categorized by Sample Type

Sample Type L Mean Std. Dev. a Mean Std. Dev. b Mean Std. Dev.

Control 79.86 0.57 0.06 0.29 16.77 0.22

50g Acai Juice Addition 59.71 0.09 1.58 0.15 8.98 0.15



Table 3 2 tailed T-Test Established Statistical Significant difference of L,a,b values between Samples. (significance level: p<0.05)

Comparison P-Value

L a b

Control vs. 50 grams juice addition 0.0003 0.0091 0.0007

Control vs. 125g juice addition 0.0104 0.0046 0.0012

Control vs.175g juice addition 0.0001 0.0068 0.0007

50g juice addition vs. 125g juice addition 0.5881 0.0052 0.0246



Figure 1 Mean L values of samples from all three trials. Mean value calculated from average of three individual readings generated via Hunter Colorimeter

Figure 2 Mean a values of samples from all three trials. Mean value calculated from average of three individual readings generated via Hunter Colorimeter

Figure 3

Mean b values of samples from all three trials. Mean value calculated from average of three individual readings generated via Hunter Colorimeter

Figure 4 Compiled L-Value of Samples of all three trials as Separated by Sample Type. Error bars shown depict std. dev. from respective calculated average

Figure 5 Compiled a-Value of Samples of all three trials as Separated by Sample Type. Error bars shown depict std. dev. from respective calculated average

Figure 6 Compiled b-Value of Samples of all three trials as Separated by Sample Type. Error bars shown depict std. dev. from respective calculated average

Table 4 Average Texture Analyzer Measured Penetration Force(g) for Trial 1, 2, and3 Samples

Sample Type Trial 1 Trial 2 Trial 3

Average Texture Analyzer Reading (g)



Control (no Acai Berry Juice Addition) 4.55 5.20 2.75

50 g Acai Berry Juice Addition 3.95 4.75 7.60

125g Acai Berry Juice Addition 2.65 2.55 4.10


Table 5 Compiled Average Penetration Force (g) for Samples of Trials 1-3 as Separated by Sample Type

Sample Type Average Texture Analyzer Recorded Penetration Force (g) Mean Std. Dev.

Control (no Acai Berry Juice Addition) 4.2 0.66

50 g Acai Berry Juice Addition 5.4 1.01

125g Acai Berry Juice Addition 3.1 0.47


Table 6 2 tailed T-Test Established Statistical Significant difference of Penetration Force(g) between Samples. (significance level: p<0.05)

Comparison P-Value

Control vs. 50 grams juice addition 0.5530

Control vs. 125g juice addition 0.4765

Control vs.175g juice addition 0.4320

50g juice addition vs. 125g juice addition 0.0337



Figure 7 Mean penetration force (g) of samples from all three trials. Mean value calculated from average of three individual readings generated via Texture Analyzer

Figure 8 Observed Penetration Force(g) of Control Samples from Trials 1-3, shown with Respective Std. Dev. from Calculated Average

Figure 9 Observed Penetration Force(g) of 50g Juice Additionl Samples from Trials 1-3, shown with Respective Std. Dev. from Calculated Average

Table 7 Observed pH levels of Trial 1, 2, and 3 Samples

Trial 1 Trial 2 Trial 3

Sample Type Average pH Average pH Average pH

Control (no Acai Berry Juice Addition) 6.29 6.36 6.41

50 g Acai Berry Juice Addition 6.51 6.27 6.40



Note: Average Observed Acai Berry Juice pH: 5.7, 5.8, 5.7 for Trials 1, 2, and 3, respectively Table 8 Compiled Average pH levels for Samples of Trials 1-3 as Separated by Sample Type

Sample Type Average pH Mean Std. Dev

Control (no Acai Berry Juice Addition) 6.4 0.04

50 g Acai Berry Juice Addition 6.4 0.06



Table 9 Statistical Significance of observed pH between various Sample Types of Trials 1-3 (statistical significance: P<0.05)

Comparison pH levels P-Value Control vs. 50g Juice Addition 0.3544 Control vs. 125g Juice Addition 0.0006 Control vs. 175 Juice Addition 0.0022

50g Juice addition vs. 125g Juice Addition 0.0148 50g Juice addition vs. 175g Juice Addition 0.0004 125g Juice addition vs. 175g Juice Addition 0.0112

Note: significance established using 1-tailed Type 1 T-test.

Figure 12 Increasing Acai Juice Addition to Respective Samples in All Three Trials vs. Respective Changes in Average Observed pH Levels. Mean pH value calculated from average of 3 individual recordings of all samples

Table 10 Average Sensory Panel Ranking of Trials 1-3 on 9-Point Hedonic Scale as Categorized by Sample Type

Sample Type Average Score Control 3.9

50g Acai Juice Addition 3.7

125g Acai Juice Addition 3.9 175g Acai Juice Addition 3.6

Figure 13 Compiled Average Sensory Panel Ranking of Samples on 9-Point Hedonic Scale; each horizontal dash is equivalent to 1/10 pt. Table 11 Compiled Frequency of Sensory Panel Rankings of Trials 1-3 Samples’ Sweetness on 9-Point Hedonic Scale

Sample Type extremely sweet (1)

very sweet (2)

Moderately Sweet (3)

Slightly Sweet (4)

Neither Sweet nor Sour (5)

Slightly Sour (6)

Moderately Sour (7)

Very Sour (8)

Extremely Sour (9)

Control 0 4 6 7 0 4 3 1 0

50g Acai Juice Addition 1 3 4 11 2 2 1 1 0



Table 12 Compiled Frequency of Sensory Panel Preference of Trials 1-3 Samples

Sample Type 1 2 3 4

Control 4 3 2 15

50g Acai Juice addition 6 9 6 3

125g Acai juice addition 5 6 10 3

175g Acai Juice addition 9 6 6 3 Note: Ranking Scale from 1-4; 1 being Most Preferred, 4 being Least Preferred

Control Extremely Sweet----------------------------X--------------------------------------------------Extremely Sour

50g Acai Juice Addition Extremely Sweet---------------------------X----------------------------------------------------Extremely Sour

125g Acai Juice Addition Extremely Sweet----------------------------X--------------------------------------------------Extremely Sour

175g Acai Juice Addition Extremely Sweet-------------------------X-----------------------------------------------------Extremely Sour

Figure 14 Compiled Sensory Panel Preference Ranking of Most Preferred Trials 1-3 Samples Table 13 Correlation Between Sensory Panel Indicated Sweetness Level and Subjective Preference

Sample Type # of People who preferred it the most Level of Sweetness

Control 4 3.9 50g Acai Juice addition 6 3.7 125g Acai juice addition 5 3.9 175g Acai Juice addition 9 3.6

Correlation Coefficient -0.9258 Table 14 Statistical Significance of Panelist Preference Frequency Distribution

Sample Type Number of People who preferred it the most Expected

Control 4 6

50g Acai Juice addition 6 6

125g Acai juice addition 5 6

175g Acai Juice addition 9 6

χ2 Test Value 0.50617

VI. References

Davis CG, Blayney DP, Yen ST, Cooper J. An analysis of at-home demand for ice cream in the United States. Journal of Dairy Science 92(12): 6210-6216.

Hogan S, Chung H, Zhang L, Li J, Lee Y, Dai Y, Zhou K. 2010. Antiproliferative and

antioxidant properties of anthocyanin-rich extract from acai. Food Chemistry 118: 208-214

Jensen GS, Wu X, Patterson KM, Barnes J, Carter SG, Scherwitz L, Beaman R, Endres JR,

Schauss AG. 2008. In Vitro and in vivo antioxidant and anti inflammatory capacities of an antioxidant rich fruit and berry juice blend. Journal of Agricultural And Food Chemistry 56(18): 8326-8333

Schiffman SS, Sattely-Miller EA, Graham BG, Bennett JL, Booth BJ, Desai N, Bishay I.

2000. Effect of temperature, pH, and ions on sweet taste. Physiology & Behavior. 68: 469-481

Schreckinger ME, Lotton J, Lila MA, de Mejia EG. 2010. Berries from South America: a

comprehensive review on chemistry, health potential, and commercialization. Journal of Medicinal Food.13(2): 233-246.

Stoner GD, Wang LS, Seguin C, Rocha C, Stoner K, Chiu S, Kinghorn DA. 2010. Multiple berry types prevent N-nitrosomethylbenzylamine-induced esophageal cancer in rats. Pharmaceutical Research 27: 1138-1145

VII. Appedix

Appendix 1 Pigments of Different Sample Types of Trials 1-3 Respectively Compared to that of Average Color Swatch

Appendix 2 Hunter Colorimeter Color Solid Scale

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