The effect of gluten-free flour substitutes on texture ... 453 Group Project Written Report The Effect of Gluten-Free Flour Substitutes on Texture, Appearance, and Palatability in

Angela Schwarz, Laura Stricker, Courtney Yaggi FN 453

Group Project-Written Report 21 November 2011

The Effect of Gluten-Free Flour Substitutes on Texture, Appearance, and

Palatability in Chocolate Chip Cookies

Angela Schwarz, Laura Stricker, Courtney Yaggi

FN 453 Group Project

Written Report

The Effect of Gluten-Free Flour Substitutes on Texture, Appearance, and Palatability in Chocolate Chip Cookies

Abstract:

Celiac Disease is a common autoimmune disorder that affects the small intestine. Patients with Celiac Disease may cause damage to the small intestine if they consume gluten, a protein composite found in foods made from wheat and other related grains. Products with gluten are common, and may include bread products such as bagels, pizza, and desserts. Gluten may give elasticity, stability, and viscosity to foods, making acceptable substitutes for gluten difficult to find for Celiac patients. The purpose of this experiment was to determine the differences in quality between gluten-free cookies and cookies with gluten, based on texture, appearance, and palatability. Pecan flour and quinoa were chosen as gluten-free flour substitutes, and all-purpose flour was the control. Using a Texture Analyzer, Hunter colorimeter, water activity meter, hedonic ranking, and preference ranking, quality of the cookies was measured. Results showed that overall quinoa flour is a good substitute for all-purpose flour in chocolate chip cookies, and pecan flour is not. Some of the main results that prove this statement are those from the sensory tests. From the 9 point hedonic scale results showed that when ranked on how hard or soft the cookies were there was no significant difference in the ratings between quinoa and the control cookies. Also for the preference test, the panelists equally chose the control and quinoa as their favorite cookies. As for the objective data, the water activity data, there is no statistical difference between the measures in water activity of the quinoa and the control cookies. Also, height and spread were not statistically different for quinoa and control, showing that the batters cook similarly. Finally the color values from the Hunter Colorimeter show that the L and a parameters for quinoa and the control are also not significantly different. Therefore the color, water activity, size and texture of the quinoa and control cookies were successfully similar. In conclusion, based on palatability, texture, and appearance, quinoa is an acceptable gluten-free flour substitute while pecan flour is not an acceptable substitute. Introduction: Celiac Disease is a lifelong, autoimmune disorder induced by the gluten proteins in wheat, rye, barley, and possibly oats. According to one source, the prevalence of Celiac Disease in America and Europe is in the range of 1:250 to 1:150 (Rewers, 2004). If patients with Celiac Disease consume gluten, an immune reaction occurs in the small intestine causing damage to the inner lining. This can lead to the inability of an individual to absorb certain nutrients (Staff- Mayo Clinic, 2011). To better absorb nutrients and limit the damage to the small intestine, Celiac patients must consume a gluten-free diet. A gluten free diet excludes any foods containing gluten, including many commonly eaten foods like wheat, barley, rye, malts, triticale, and possibly oats (Gluten-free diet, 2011). Because of the high prevalence of wheat and wheat products in the food market, the demand for gluten-free products for patients with Celiac Disease is high. The goal of

this experiment is to make a commonly eaten food product with gluten-free flour substitutes. Chocolate chip cookies were chosen because of their popularity and because flour can be easily substituted in the recipe. Flour substitutes in this experiment are quinoa, a grain like crop with nutrient composition comparable to common cereals (Gluten-free diet, 2011), and pecan flour, a baking flour made from pecan nuts (Turner, 2011). These flours may be a good choice not only because they are gluten-free, but also because they may add some nutritional value with the incorporation of fiber, which is a nutrient that this population is often lacking. This is seen in Schoenlechner and Berghoter's study in which they completed trials using quinoa flour in bread and found that bread quality and nutritional aspects were improved in gluten-free products as long as dough moisture could be increased (Gallagher, 2004). There have been some studies done to test the quality of cookies when using gluten-free flour. Singh et al performed a study in which they used sweet potato flour in chocolate chip cookies to make the cookie either low gluten or gluten-free and to add fiber to the cookie. They found that if a cookie was only 40% gluten-free flour, it was still acceptable to the population; but once they made it completely gluten-free, the population's acceptance of the cookie dropped significantly (Singh, 2008). They also found that the L value decreased significantly and the b value increased significantly in terms of color. However, the positive outcome they did find was that the texture of the cookie was tender and acceptable, even when completely gluten-free (Singh, 2008). These findings show the challenges likely to be faced when trying to formulate a gluten-free cookie. The tests that will be performed to measure quality of the product have all been deemed to be important by those who often test for acceptable substitutes with gluten-free products. Crumb texture is often times affected by the absence of gluten in the product. Sciarni et al found that when doing a study using rice, soy, and corn flours, all were deemed to have low rate of crumb hardening but a lower volume. Therefore, texture is something that should be tested for in these products. Thus, the Texture Analyzer will be used to test for the crumb texture. Sciarni et al also found in their study that the different flours caused different color appearances. The corn flour products had much lighter crusts where the rice flours had much darker crusts. When dealing with gluten-free products a darkening of the crust is much more desirable because gluten-free products often times tend to have a lighter appearance than regular bread products (Sciarni, 2008). Therefore, color measurements will be done using the Hunter colorimeter with the products as well to examine which has a more desirable visual appearance. The water activity meter was used to evaluate the products water activity level. Determining a products water activity level is important in evaluating mouthfeel, flavors, and aromas of products. (Decagon, 2011) Lastly, the subjective testing methods are extremely valuable because the main point of creating these products is to make an acceptable item for people with Celiac Disease. It is imperative that the product has an appropriate taste as well as look or the consumers are not going to want to eat or buy the product. A Hedonic Ranking Scale will be evaluated by a panel to rate hardness or softness of the product, as well as a ranking of preference. Methods:

In this experiment tests were conducted to find whether gluten free flours can be

used interchangeably with flours containing gluten in chocolate chip cookies. Throughout the experiment, the goal was to determine if gluten-free flours would change a regular all-purpose flour chocolate chip cookie in terms of texture, appearance and overall preference/palatability. In order to do this, a recipe was found for chocolate chip cookies from allrecipes.com that used all-purpose flour. This was used as the control recipe, since chocolate chip cookies are normally made with gluten. For the variables, quinoa flour, and pecan flour (meal) were used, which are both gluten free flours. During each of the trials one member at a time was baking the control, quinoa, and pecan cookies, while another member was taking objective measurements and the third member then was conducting the subjective tests. The schedule of tasks for each trial is recorded in Table A below.

To begin, the member making the cookies that week started off making the quinoa cookies, then the pecan cookies, and then their final batch the control cookies. This schedule was strictly set and met to keep from having wheat flour in the presence of two cookies that were going to be gluten-free. To begin the experiment the oven was preheated to 325 degrees F, and all ingredients were measured out by cutting the recipe for “Best, Big Fat Chewy Chocolate Chip Cookies” recipe in half. The ingredients were measured with a scale for the most accurate measurements. The 125grams (g) of flour (First trial quinoa, Second pecan, third all-purpose flour), 1.5g salt, and 1g of baking soda were sifted into a medium size bowl and set aside. The next step was to melt the 85g unsalted butter for 45 seconds on high heat in the microwave. The butter was then creamed with the 110g of packed dark brown and 57.5g of white granulated sugar in a large bowl for 1 minute on high. Once a minute has passed the sides of the bowl were scraped down with a spatula, and then the mixture was mixed again on high for 30 seconds. Next the 1/2 egg, 1/2 egg yolk, and the 7.5ml of vanilla were combined in the same bowl. To correctly measure half of an egg, the egg was beaten with a fork, then weighed and half of the contents was then used the in batter. For the egg yolk the same methods were used, the yolk was separated from the white, beaten, weighed, then half was used in the batter. The egg, butter, sugar and vanilla mixture was mixed with an electric hand mixer on medium speed for 2 minutes. The dry ingredients were mixed into the butter mixture in 2 steps. First half of the dry ingredients was added to the large bowl containing the creamed wet ingredients and mixed for 30 seconds on medium speed. After 30 seconds the sides of the bowl were scraped down with a spatula, and add the other half of the dry ingredients were added and mixed again for 30 seconds on medium speed. Once the mixture was completely mixed, the sides of the bowl were scraped down again with a spatula and the 1675g of chocolate chips were folded into the batter 10 times with a wooden spoon. Finally a standard size ice cream scoop, with a knife to level the dough in the scoop, was used to properly size the cookies onto a parchment lined baking sheet. Each scoop of dough was placed 3 inches away from the next with a total of 9 cookies per a try. The baking time for all cookies the baking time was controlled at 15 minutes. Once cookies were baked they were cooled on a wire rack.

Once the cookies cooled the objective measurements were taken and recorded by the designated person for that trial. The Stable Micro Systems Texture Analyzer was used to test the breaking strength of the cookie using the knife probe. The water activity meter was used to test the water activity in the cookies, and the Hunter Colorimeter tested the color differences between the cookies. The final objective measurements taken were

the length and height of the cookies using a Vernier Caliper and recorded in centimeters (cm). These two measurements were important in determining how different cookie batters melted and spread. To find the specific methods used for each of the objective methods equipment used in this experiment, please reference The Food Chemistry Laboratory written by Connie M. Weaver and James R. Daniel, 2003 pages 111-112,127-130,132. The subjective methods were used to evaluate how consumers would judge a gluten free cookie compared to a cookie made with wheat flour (gluten). The specific subjective methods used were the 9- point hedonic ranking scale based on hardness/softness of the cookies, and a preference test of which cookies tastes the best. The panel used for the subjective testing were college students ranging from ages 19-30, both men and women. Samples pf the hedonic scale used and preference test are located below in Table C, and decoding for subjective tests in table C.1.

Table A: Schedule of Tasks for Trials 1, 2, and 3.

Trial Preparation Objective Methods Subjective

Methods

1 Angela Courtney Laura

2 Laura Angela Courtney

3 Courtney Laura Angela

Table B: List of Ingredients and materials used for all tests conducted Metric Units: 375 g All Purpose Flour 375g Quinoa Flour 375g Pecan Flour 9g Baking Soda 13.5g Salt 765g Unsalted Butter 990g Dark Brown Sugar 517.5g of White Granulated Sugar 67.5mL Vanilla Extract 9 eggs 1507.5 g Semi -Sweet Chocolate Chips Parchment Paper US Measurements: 3 Cups All Purpose Flour 3 Cups Quinoa Flour

3 Cups Pecan Flour 2 ¼ tsp Baking Soda 2 ¼ tsp Salt 7.5 sticks of Unsalted Butter (60 TBS) 4.5 Cups Dark Brown Sugar 2 1/4 cups White Granulated Sugar 4.5 Tbs Vanilla Extract 9 eggs 9 cups of Semi-Sweet Chocolate chips Parchment paper Supplies: Ovens 6 Baking sheets 3 Sifters 3 Medium bowls 3 Large Bowls (big enough for hand mixing dough) 3 Wooden Spoons 1 Roll of paper towels 3 Metal Spatulas 3 Silicone scrapers (Other type of spatulas) 3 Sets of Measuring cups 3 Sets of Measuring spoons 3 Small Microwaveable Bowls 3 Knifes (Table utensil knifes) 3 Ice cream scoops with scraping handle Table C. Sample of Subjective Test Forms Hedonic Ranking Sample Form and Preference Testing Form Sensory Evaluation Trial 1. Please taste each sample in front of you. On the scale below please mark the line that best describes each cookie. 319 Very soft Slightly Soft Slightly hard Very hard

l_______l_________l________l________l________l________l________l________l Extremely soft moderately soft neither soft moderately hard extremely hard Nor hard

511 Very soft Slightly Soft Slightly hard Very hard



l_______l_________l________l________l________l________l________l________l

Extremely soft moderately soft neither soft moderately hard extremely hard Nor hard Rank the samples in order of preference, where 1 is the one you like most and 3 is the one you like least.

319 _______

511 ________

912 ________ Sensory Evaluation Trial 2. Please taste each sample in front of you. On the scale below please mark the line that best describes each cookie. 920 Very soft Slightly Soft Slightly hard Very hard





l_______l_________l________l________l________l________l________l________l Extremely soft moderately soft neither soft moderately hard extremely hard Nor hard Rank the samples in order of preference, where 1 is the one you like most and 3 is the one you like least.

920 _______

529 ________

324 ________ Sensory Evaluation Trial 3. Please taste each sample in front of you. On the scale below please mark the line that best describes each cookie. 937 Very soft Slightly Soft Slightly hard Very hard





l_______l_________l________l________l________l________l________l________l Extremely soft moderately soft neither soft moderately hard extremely hard Nor hard Rank the samples in order of preference, where 1 is the one you like most and 3 is the one you like least.

937 _______

530 ________

336 ________ Table C.1 Decoding Table for Samples in Subjective Testing Trial 1 Trial 2 Trial 3

Quinoa 912 920 937

Pecan 511 529 530

Control 319 324 336

Discussion:

The effects of adding gluten-free flours in substitution for all-purpose flour in chocolate chip cookies resulted in quinoa being successfully substituted for all-purpose flour for most subjective and objective measurements. Pecan flour was not as successful in substitution and only resulted in a few common measurements. To begin, in analyzing the measurements from the Texture Analyzer, referring to Table 1, the total averages for the force in grams used to break the cookies, were extremely different. The control all-purpose flour cookies had the highest average force, and pecan flour had the smallest average force, with quinoa being close in the middle of the two values. However, when the information was statistically evaluated, Table 1.1 and Figure 1 show that quinoa and the control flours were not statistically different. Also quinoa and pecan flours force were not statistically different, with pecan being significantly different than the control. This information shows that statistically, when

eating a quinoa and a control cookie, the breaking strength or texture would be similar. Also, this information shows that the same is true for quinoa and pecan, but when comparing pecan and control there would be a definite difference in texture. When evaluating the texture using the subjective measurements, the results showed that the pecan cookie was significantly different than both the quinoa and control cookies. The method used for subjective measurements was the 9-point Hedonic scale, with 1 being extremely soft and 9 being extremely hard. Table 5 shows the average ratings for each of the cookies, in which quinoa and control had the most similar averages, and were rated to be “neither soft nor hard” to “slightly hard.” Pecan’s average hardness was much lower than the other two, and was rated “very soft” to “moderately soft.” Table 5.1 and Figure 5 show that quinoa and control statistically have no difference, while pecan statistically different from both. Again these results show that quinoa does not affect texture in substitution for all-purpose flour in cookies, while pecan flour does. Water activity results showed that there was no significant difference between the water activity of the quinoa cookie and pecan cookie, as well as no difference between the control cookie and the quinoa cookie. However, pecan and control were significantly different according to statistical analysis. Differences in water activity can affect mouthfeel, flavors, and aromas of products. An important measurement was that of the color differences of the cookies using different flours. The Hunter Colorimeter was used to evaluate this. The results were that in the “L” value, in which a higher value represents a lighter color, and a smaller value represents a darker color, quinoa was the lightest and pecan was the darkest based on their values. For the “a” parameter, which evaluates red (+) to green (-), all “a” values for all three cookies were positive, and therefore closer to a red pigment. Control was the highest, followed by quinoa, then pecan. For the “b” parameter, which evaluated yellow (+) to blue (-), all values were positive, with the highest value being quinoa, then control, then pecan. Referring to Table 3.1 and Figure 3, the statistically analyzed data is represented, showing that for the “L” values there is no significant difference between the control and the quinoa and that pecan is different from both of the other. For the “a” values, control and quinoa are not significantly different, and control and pecan are not significantly different, but pecan and quinoa are statistically different. Finally, for the “b” values, all three are statistically significantly different. These results show that when judging appearance based on color of the different flours in the cookies, quinoa and control had the most similar results. The final objective measurement used was the evaluation of the height and spread of the cookies after baking using a Vernier Caliper. Table 4.1 and Figure 4 show that the sizes of the cookies in spread, the quinoa and control were not significantly different, but that pecan was significantly different from the other two. This was expected due to the thin batter that the pecan meal provided. In evaluating the height the cookie rose, quinoa and control were not significantly different and pecan was significantly different from the two. This information shows that the ability of the quinoa and control cookies to rise and spread were similar, thus the change of quinoa flour for all-purpose flour results in the same size cookies. The final subjective measurement was based consumers’ preferences to determine the palatability of the cookies, and which was most preferred. A preference test was used,

with 1 being the most preferred, and 3 being the least preferred. Based on the averages (Table 6) results showed that quinoa and control had very similar ratings, and quinoa was the preferred cookie. The quinoa rating was 1.5, control’s rating was 1.7, and pecan was least at 2.6. When adding up the scores of the cookies to see which cookie received the most votes for preferred cookie, quinoa and control were tied for first with both having 40% of the votes for first place. When statistically analyzing these results, quinoa and control had no significant differences, and pecan was significantly different than the other two. These results show that quinoa is a successful substitute for all-purpose flour cookies in taste and palatability. Sources of error for this experiment may include the different places on the pan that the cookies baked. Cookies on the outer edge of the pan may have had a chance to bake more thoroughly, resulting in a harder texture on the Texture Analyzer and on the Hedonic scale. This may also affect the color of the cookies, which may have received more browning from the baking. In addition, the rise may have been affected. When using the texture analyzer, errors could have been made by the knife probe hitting a chocolate chip instead of a part of the flour-substituted part of the cookie. This would result in a higher or lower force exerted, since chocolate chips may be softer or harder than the other part of the cookie after baking. The chocolate chips may have also affected the Hunter colorimeter readings, based on the darkness of the chips. More chips in the sample may have resulted in a darker reading and affecting color. More chocolate chips in a sample may have also affected the measure of the water activity meter. Depending on the amount of chips in the sample, the water activity value could have been less or more, causing a large standard deviation between samples. The chocolate also could have been the result of higher values for cookie heights if the Vernier Caliper was measuring a chocolate chip which sticks out of a cookie. Chocolate chips could have also affected the preference ratings of the cookies, if a participant had a cookies loaded with chips versus one lacking chips, resulting in a panelist liking the one based solely on the chocolate and vice versa. The baking methods could also been a source of error. The ovens used were not the same models and they were not tested for accurate temperatures. The temperatures were based on the electronic settings. The cookies in the different ovens were either baked alone or had other sheets of cookies baking with them at the same time. If more than one baking sheet was in an oven, then one sheet was higher than the other. These two things can affect the overall temperature inside because of more product baking. Also the heat source was either further or closer away to the baking cookies depending on placement on racks. The final source of error had to do with the time frame in which the cookies were baked and then evaluated. Because of time constraints, the cookies were baked and put in plastic baggies overnight. From the cookies being left overnight they could have had more time to harden and therefore resulted in higher force loads for the Texture Analyzer measurements, and higher ratings in the 9-point Hedonic Scale sensory test. If the experiment was to be replicated, it is in the experimenter’s best interest to bake all cookies in the same oven, on the same rack, one at a time, and with the same amount of chocolate chips in each cookie. Also the measurements, both subjective and objective, should be done as soon as possible.

In conclusion quinoa is an acceptable substitute for gluten flours, specifically all-

purpose flour, to create gluten free cookies. Pecan meal, however, proved to be too heavy and too dark, and did not produce similar results to the control cookie. For patients affected with Celiac Disease, it is an interesting find that quinoa, being a successful replacement in chocolate chip cookies, may result in more substitutions in baking for them in the future. Results: Table 1:Texture Analyzer results for Quinoa Flour, Pecan Meal and the Control All-purpose Flour with Averages and Standard Deviation Trial Quinoa Pecan Control TA (g) TA (g) TA (g) T1.1 5384.5 3807.3 20262.0 T1.2 2175.2 5881.6 11477.327 T1.3 1714.4 5400.3 6858.751 Average: 3091.3 5029.7 12866.0 T2.1 5724.4 2636.5 6581.513 T2.2 3100.2 753.3 1654.066 T2.3 2808.3 1589.2 4521.838 Average: 3877.6 1659.7 2745.2 T3.1 2013.0 772.2 4730.8 T3.2 5133.7 2003.6 5584.4 T3.3 4910.1 2876.2 5760.0 Average: 4018.9 1884 5358.4 ________________________________________________________________________ Total Averages: 3662.6 2857.8 7492.3 STD Deviation: 1609.017 1859.98 5446.93 Table 1.1 Texture Analyzer Result Means with Statistically Significant Data Sample: Average Force in grams (g) ________________________________________________________________________ Control: 7492.3A

Quinoa: 3662.64AB

Pecan: 2857.8B

________________________________________________________________________ Averages not bearing the same superscript are statistically significantly different, p<0.05.

Texture Analyzer

AB

A

0

2000

4000

6000

8000

10000

12000

14000

Quinoa Pecan Control

Samples

Fo

rce

in G

ram

s (g

)

Texture AnalyzerB

*Averages not bearing the same superscript are statistically significantly different, p<0.05.

Figure 1: Texture Analyzer results for Quinoa Flour, Pecan Meal and the Control All-purpose Flour with

Averages and Standard Deviation

Table 2: Water Activity results for Quinoa Flour, Pecan Meal and the Control All-purpose Flour with Average and Standard Deviation Trial Quinoa Pecan Control aW, °C aW , °C aW, °C T1 .481 23.3 .567 23.7 .417 24 T2 .427 23.7 .560 23.8 .616 23.9 T3 .446 27.7 .583 24.3 .528 23.4 Averages: .451 24.9 .570 23.9 .520 23.8 Std Dev: .0274 .0118 .0997

Table 2.2: Water Activity Average Results for Quinoa Flour, Pecan Meal and the Control All Purpose Flour Cookies Statistically Significant Differences Samples: aw averages ________________________________________________________________________ Pecan: .570A

Control: .520B

Quinoa: .451AB

________________________________________________________________________ Averages not bearing the same superscript are statistically significantly different, p<0.05.

Table 3: Hunter Colorimeter results for Quinoa Flour, Pecan Meal and the Control All-purpose Flour Cookies with Average and Standard Deviation Trial Quinoa Pecan Control L a b L a b L a b T1.1 52.27 6.71 19.78 23.49 5.81 7.62 52.51 6.16 17.81 T1.2 50.81 5.80 18.66 21.70 4.77 6.65 48.40 7.89 17.61 T1.3 52.18 6.13 19.32 22.37 4.44 5.72 47.77 6.40 16.50 T2.1 52.14 5.34 18.86 28.06 5.92 9.08 37.93 10.88 15.73 T2.2 7.69 7.72 18.6 24.36 5.67 7.17 38.94 11.38 16.22 T2.3 50.82 5.96 19.15 26.02 6.52 8.31 41.95 11.28 17.45 T3.1 51.38 7.07 19.45 24.02 5.19 6.94 54.08 5.11 17.31 T3.2 47.25 9.07 18.96 23.78 5.10 6.86 54.67 6.08 18.64 T3.3 50.94 5.26 19.08 24.02 5.18 6.94 54.36 7.33 19.34 ________________________________________________________________________ Avg: 50.61 6.56 19.1 24.2 5.40 7.25 47.85 8.06 17.4

SD: 1.88 1.24 0.38 1.89 0.64 0.98 6.73 2.47 1.15 Table 3.1: Hunter Colorimeter Result Averages with Statistically Significant Data L-Values a-Values b-Values ________________________________________________________________________ Quinoa 50.61A 6.56CD 19.1E

Control 47.85A 8.06C 17.4G

Pecan 24.2B 5.40D 7.25F

____________________________________________________________________________________________________________

Averages not bearing the same superscript are statistically significantly different, p<0.05.

Table 4: Height and Spread Measurements of Cookies baked with Quinoa, Pecan Meal, and Control- All purpose Flour with Averages and Standard Deviations Trial Quinoa (cm) Pecan (cm) Control (cm) Height, Spread Height, Spread Height, Spread T1.1 6.5 11.9 3.1 15.2 6.5 11.4 T1.2 6.0 11.4 3.2 14.7 7.0 11.4 T1.3 7.0 11.4 3.0 15.5 8.0 11.2 T2.1 5.0 14.2 3.1 15.7 6.5 14.0 T2.2 6.0 12.7 3.0 13.7 7.5 10.9 T2.3 4.0 13.2 3.1 14.0 5.5 10.9 T3.1 5.0 11.7 3.0 15.2

5.5 13.7 T3.2 6.0 12.4 3.0 14.7 5.5 13.0 T3.3 5.1 11.7 3.1 14.7 5.5 11.9 ________________________________________________________________________ Avg: 5.6 12.29 3.1 14.82 6.4 12.04 SD: 0.92 0.94 0.07 0.66 1.12 1.21 Table 4.1: Averages of Height and Spread of Quinoa, Pecan Meal, and Control Cookies and the Statistically Significant Data Quinoa Pecan Control ________________________________________________________________________ Height (cm): 5.6A 3.1B 6.4A

------------------------------------------------------------------------------------------------------------ Spread (cm): 12.29C 14.82D 12.04C

________________________________________________________________________ Averages not bearing the same superscript are statistically significantly different, p<0.05

Table 5: Results from 9 Point Hedonic Test for Quinoa Flour, Pecan Meal, and Control All-Purpose Flour Chocolate Chip Cookies for the Evaluation of Texture/ Hardness Participant Quinoa Pecan Control 1= Extremely Soft 9= Extremely Hard ________________________________________________________________________ Trial

1 1 5 4 8 2 4 3 6

3 4 1 8

4 7 3 6 5 5 3 6

Trial 2 1 6 4 4

2 2 3 4 3 3 1 6 4 2 1 5 5 4 3 4

Trial 3 1 6 4 4

2 4 3 6 3 5 1 5 4 3 2 4 5 4 3 3

________________________________________________________________________ Averages: 4.3 2.6 5.3 Std Dev: 1.44 1.12 1.49

Table 5.1 Results from 9 Point Hedonic Test for Quinoa Flour, Pecan Meal, and Control All-Purpose Flour Chocolate Chip Cookies for the Evaluation of Texture/ Hardness and Statistically Significant Differences. Samples: Average Ratings 1= Extremely Soft 9= Extremely Hard ________________________________________________________________________ Control: 5.3A

Quinoa: 4.3A

Pecan: 2.6B


Table 6: Average Rating Results from Preference Test for Quinoa Flour, Pecan Meal,

and Control All-Purpose Flour Chocolate Chip Cookies on Palatability Participant Control Pecan Quinoa 1= Like Best 3= Like Least ________________________________________________________________________ Trial

1 1 2 1 2 2 1 3 1

3 1 3 1 4 2 3 2 5 1 3 1

Trial 2 1 2 1 2

2 2 3 2 3 1 3 1 4 1 3 1 5 2 3 2

Trial 3 1 2 1 2

2 2 3 2 3 1 3 1 4 1 3 1 5 1 3 1

________________________________________________________________________ Averages: 1.7 2.6 1.5 Std Dev: 0.617 0.828 0.516

Table 6.1: Average Rating Results from Preference Test for Quinoa Flour, Pecan Meal, and Control All-Purpose Flour Chocolate Chip Cookies on Palatability with Statistically Significant Differences Samples: Average Ratings 1= Like Best 3= Like Least ________________________________________________________________________ Pecan: 2.6B

Control: 1.7A

Quinoa: 1.5A


References: Decagon Services. 2011. “Water Activity Theory”. Wateractivity.org. 13 November

2011. <http://www.wateractivity.org/theory> Gallager, E., Gormley, T.R., and Arendt, E.K. 2004. Recent Advances in the Formulation

of Gluten-Free Cereal –Based Products. Trends in Food Science & Technology. 15 (3-4): 143-153.

<http://www.sciencedirect.com/science/article/pii/S0924224403002590#bBIB6>. “Gluten-free diet.” 2011. Wikipedia, the free encyclopedia. 13 November 2011.

<http://en.wikipedia.org/wiki/Gluten_free_diet>. Rewers, Marian. 2005. Epidemiology of celiac disease: What are the prevalence, incidence, and progression of celiac disease? Journal of Gastroenterology. 128(4)1: S47-S51. <http://www.sciencedirect.com/science/article/pii/S001650850500199X>. Sciarni, L. S., Ribotta, P. D., Leon, A. E., & Perez, G. T. 2008. Influence of Gluten-free Flours and their Mixtures on Batter Properties and Bread Quality. Food and Bioprocess Technology. 3(4): 577-585. Singh, S., Riar, C., &Saxena, D. 2008. Effect of Incorporating Sweet potato Flour to Wheat Flour. African Journal of Food Science. 2: 65-72. Staff-Mayo Clinic. “Celiac Disease.” 2011. MayoClinic.com. Mayo Foundation for

Medical Education and Research. 13 September 2011. <http://www.mayoclinic.com/health/celiac-disease/DS00319>.

Turner, B. “What is Pecan Flour?” 2011. WiseGeek.com. Conjecture Corporation. 27 September 2011. <http://www.wisegeek.com/what-is-pecan-flour.htm>.

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The effect of gluten-free flour substitutes on texture ... 453 Group Project Written Report The Effect of Gluten-Free Flour Substitutes on Texture, Appearance, and Palatability in