Title: The Use of Pumpkin Puree as a Fat Replacement in ... The Use of Pumpkin Puree as a Fat Replacement in Chocolate Cupcakes Abstract: An emerging challenge in the food industry

Title: The Use of Pumpkin Puree as a Fat Replacement in Chocolate Cupcakes

Abstract:

An emerging challenge in the food industry is to utilize fat replacers in products while still

obtaining the most desirable qualities that people associate with full-fat foods. The problem with

most fat replacer is that they fail to reach the desirable flavor, leavening, moisture, and

tenderness. The methods used to replace oil for pumpkin puree was simply a 1:1 replacement of

the required oil amount for pumpkin puree. It was found that using the pumpkin puree as an

alternative to fat was not statistically different in the following categories: Softness, Moisture,

and Overall Preference. Using a pumpkin puree as a fat replacer is a good method to reduce the

fat content and total calories in chocolate cupcakes without significant changes in objective and

sensory variables.

Introduction:

An emerging challenge in the food industry is how to create products that are lower or void of fat

yet still have the same desirable qualities that people associate with in their favorite full-fat

foods. Replacing oil with a fat replacer can also improve nutrition by decreasing total fat and

calories (American Dietetic Association, 2005). This becomes difficult especially with baked

goods because fat is very important in providing flavor, richness, aeration, tenderness, flakiness,

smooth mouth feel, leavening, and moisture retention (Lucca and others 1994). Using fat

replacers is very popular and can be classified as carbohydrate or protein-based and is

manufactured to mimic the fats commonly found in a wide variety of foods. However, other

foods, such as pumpkin puree in our experiment, can be used to replace fat in a product that is

more easily accessible than what the food industry uses. Pureed pumpkin contains pectin which

is a polysaccharide, and makes pureed pumpkin a good carbohydrate-based fat replacer.

Polysaccharides interact well with water by controlling the structure and mobility of water. Due

to the fact that pectin is not hydrophobic like oil, it inhibits gluten formation by competing with

flour to bind water which will increase viscosity, lubricity, and gel formation (Min and others

2010). The resulting product using a carbohydrate-based fat replacer will mimic the lubricity and

viscosity of fat containing baked goods (Sanchez and others 1995). The purpose of this

experiment was to observe the effects of replacing oil with pumpkin puree in chocolate cupcakes

in order to decrease total calories and fat without negatively compromising palatability. The

independent variables included a control cupcake with full oil, a ½ pumpkin puree and ½ oil

cupcake, and a cupcake with full replacement of oil with pureed pumpkin. The dependent

variables include objective data from the viscometer, height and diameter measurements, and

texture analyzer and subjective data from rankings and structured ratings.

A variety of methods are available to test for viscosity, leavening, texture, and consumer

acceptability. The viscosity was measured using a Brookfield viscometer because it is an indirect

measure of liquid texture (Weaver and Daniel 2003). It was necessary to measure the liquid

texture because the viscosity of the batter can affect the texture and leavening of the final

product. Stefan Palzer from the Nestle Research Center Lausanne identified that replacing the

fat in a product with a fat replacer will often increase the viscosity of the product (Palzer 2009).

This will be expected in our cupcakes because pumpkin puree is thicker than oil. In order to

measure leavening, the diameter and height of each cupcake were measured in millimeters once

they were cooled to room temperature. This method was implemented because it results in an

assessment of leavening in the final product. Greater leavening is associated with density and

texture of baked goods. Texture was assessed objectively using the Texture Analyzer. This

measure was important to our data collected because it directly measures texture by puncturing

the cupcake and measuring the force needed to penetrate the surface of the cupcake (Weaver and

Daniel 2003). According to Alphons G.J. Voragen from the Department of Food Technology,

using a carbohydrate-based fat replacer may improve the texture of the final product (Voragen

1998). Consumer acceptability was measured using a structured rating and ranking evaluation.

In order to determine overall acceptability by the consumer, a ranking evaluation of the three

variables was used. Structured rating evaluated sensory qualities of softness, moistness, and

overall acceptance. These qualities were important to measure because they were related to our

objective measures of viscosity, leavening, and texture.

Methods:

Overall Design and Procedures

A box mix was used to standardize the recipes and canned pumpkin puree was used to replace

vegetable oil. Betty Crocker super moist chocolate cake mix and Payless store canned brand

pumpkin puree, vegetable oil, eggs, and tap water was used. The recipe for cupcakes was taken

from the back of the box of cake mix. Each recipe was divided in half to conserve ingredients.

Five boxes total were used to make a total of nine different cupcakes (3 variables, triplicated).

Directions for making the cupcakes were followed from the box mix. Cake mix, pumpkin puree,

and egg were measured by weight. Water and oil were measured by dividing each ingredient in

half by using a liquid measuring cup. The ingredients were then placed in a large bowl and

mixed using a rubber spatula for 2 minutes. Paper cupcake liners were used and each pan cavity

was filled to 2/3 capacity. The cupcakes were baked for 25 minutes in a conventional oven at

350o F (177o C). The cupcakes were served at room temperature and without a carrier such as

icing. Objective measures utilized include the Brookfield Viscometer, Texture Analyzer, and the

diameter and height. Subjective data was collected by a panel 13 semi-trained Purdue University

Nutrition Science students completing a ranking and structured rating evaluation (See

Appendix). Panelists completed the evaluation in the middle of the afternoon (4:30 pm) and did

not rinse their mouths between samples.

Table 1: Ingredient amounts for each variable

Ingredients

Control (full

oil)

Variable 1 (half

oil, half

pumpkin)

Variable 2 (full

pumpkin)

Betty Crocker Box

Mix

217 g 217 g 217 g

Eggs 1.5 1.5 1.5

Water 115 g 115 g 115g

Vegetable Oil 36.5 g 18 g 0 g

Canned Pumpkin

Puree

0 g 20.5 g 41 g

Table 2: Settings for objective measures

Instruments Settings

Brookfield Viscometer Probe 5, 12 rpm

Texture Analyzer Cone probe, auto setting

Diameter cm

Height cm

Replications, Randomization, and Sampling

All 3 trials were completed on the same day to ensure consistent lab conditions. Test subjects

volunteered for the subjective evaluation. In order to prevent sampling bias a random, 3-digit

number was assigned to each of the 3 variables and the control was not served first. 506 was

assigned to the control, 422 was assigned to the ½ pumpkin, ½ oil variable, and 302 was

assigned to the full pumpkin variable.

Discussion:

In quantifying our qualitative data we assigned a ranking number to each of the choices on the

sensory evaluation. They were assigned numerically starting from most soft with a value of one

to extremely tough with the value of 7. Moisture was evaluated by assigning the value of 1 to

extremely moist, and the value of 7 to extremely dry. Preference was evaluated by assigning the

value of 1 to like extremely and the value of 7 to dislike extremely. Overall ranking was also

analyzed in this way by assigning the value of 1 for most preferred and the value of 3 for least

preferred. The number of responses was multiplied by the assigned values for the qualitative

choices given. These results were then added and divided by 14 which was number of subjects

who completed the evaluation. Therefore the smallest average number was the most desirable.

Sample Calculation: [(1*5)+(2*2)+(3*1)+(4*1)+(5*3)+(6*1)+(7*1)]/14 = 3.14

After statistical analysis of the objective data using an ordinary ANOVA, it was determined that

there were no significant differences between variables in regards to texture, viscosity, and

height (Tables 3-6; Figures 1-2, 4). Our data contrasts that of Lucca and Tepper which found

that carbohydrate based fat replacers will increase the viscosity of foods by creating a gel-like

matrix which stabilizes large amounts of water (Lucca and Tepper 1994; Khalil 1998). Sanchez

and others also found a significant increase in breaking strength of cookies when using a

carbohydrate based fat replacer. They also found no significant difference in height which is

what was determined by our research as well (Sanchez and others 1995). However, some

research does suggest an increase in height with the use of carbohydrate-based fat replacers

along with an emulsifier (Khalil 1998). Regarding the current data, there was a statistical

difference in diameter (Table 3-6; Figure 3). The control verses pumpkin was significantly

different at p<0.05, and the ½ and ½ verses pumpkin was significantly different at p<0.01. This

suggests greater leavening with increasing replacement of oil with pumpkin. The data is

encouraging because there is no significant difference in the majority of objective data when

replacing oil with pumpkin. Similar research from John F. White and others determined in their

research that using a fat replacer to reduce calories is more efficient than reducing carbohydrate

content (White and others 1989). This leads to a lower fat and calorie cupcakes with few changes

in objective measurements.

Similar results were found with subjective data. No significant results were found when an

ordinary ANOVA was run between the three variables at a significance of p<0.05. Again, this

data shows that there are no differences detected in regards to moisture and softness according to

the panelists. Research from Sanchez and others using a carbohydrate based fat replacer found

that moisture content increased with increasing fat replacer (Sanchez 1995). The data also

suggests there is no significant difference in consumer acceptance for overall preference and

ranking. Past research has suggested that only up to 50% replacement of fat with a fat replacer is

desirable to maintain sensory characteristics (Zoulias and others 2002; Khalil 1998). However,

our research with pumpkin as a fat replacer in chocolate cupcakes suggests that full replacement

of fat with a substitute shows no significant differences in sensory characteristics. Since the goal

of this experiment was to determine if pumpkin is an acceptable fat replacer in chocolate

cupcakes, the conclusion can be drawn that the experiment was a success and pumpkin is an

excellent option for reducing fat and calories in chocolate cupcakes.

Sources of error for this experiment include measurement error when halving the recipe to

prevent waste of batter. When the recipe was cut in half, 1.5 eggs were required which required

whisking the egg before measuring. The texture of the final product could be altered if different

amounts of yolk and white were incorporated into the cupcakes. A second source of error is the

Brookfield Viscometer. On two occasions, the viscometer would not give a reading on our batter

because it was too thick. This could be traced back to measurement error of the ingredients. A

final source of error would be the amount of batter that was placed in each cupcake cavity. Each

cavity was filled to 2/3 capacity which was not a standardized amount by weight. The amount of

batter in each cavity could have impacted height and diameter of the cupcakes.

The take home message is there is no difference in objective or subjective tests. This means that

to the consumer there was no difference in overall preference between the control cupcake and

the pumpkin cupcake. By adding pumpkin to cupcake batter the calories will be decreased and

there will be added nutritional benefits. Cupcake recipes can be altered to increase nutritional

value without compromising taste.

A suggestion for further work would be to replace the oil in cupcakes with other fruits or

vegetables. Since our data concluded that full replacement of oil with pumpkin shows no

significant changes in objective and subjective data, further research is needed to see if other

fruits and vegetables are equally successful. More research could determine if pumpkin is an

adequate fat-replacer in other baked goods such as cookies or brownies.

Results:

Objective Data

Table 3: Control cupcake objective data

CONTROL TA (G) VISCOSITY

(12RPM)

DIAMETER

(CM)

HEIGHT

(CM)

TRIAL 1 18.7 N/A 7.1 4.2

TRIAL 2 24.7 15300 6.5 4.5

TRAIL 3 34.7 17200 6.5 4.5

AVERAGE 26.03 16250 6.70 4.40

STANDARD

DEVIATION

8.08 1343.50 0.35 0.17

Table 4: ½ oil, ½ pumpkin cupcake objective data

1/2 AND 1/2 TA (G) VISCOSITY

(12RPM)

DIAMETER

(CM)

HEIGHT

(CM)

TRIAL 1 27.3 14500 7 4.8

TRIAL 2 18.4 N/A 7.5 5

TRAIL 3 30.9 13200 7.5 5

AVERAGE 25.53 13850 7.33 4.93

STANDARD

DEVIATION

6.43 919.24 0.29 0.12

Table 5: Full replacement of oil with pumpkin objective data

PUMPKIN TA (G) VISCOSITY

(12RPM)

DIAMETER

(CM)

HEIGHT

(CM)

TRIAL 1 21.8 17730 6 3.8

TRIAL 2 26.5 12200 6 3.75

TRAIL 3 16.5 13200 6 4

AVERAGE 21.60 14377 6.00 3.85

STANDARD

DEVIATION

5.00 2946.80 0.00 0.13

Table 6: Statistical analyses of objective data.

Comparison (TA) Difference q P value

================================== ========== ======= ===========

Control vs 1/2 and 1/2 0.4000 0.07696 ns P>0.05

Control vs Pumpkin 3.600 0.6926 ns P>0.05

1/2 and 1/2 vs Pumpkin 3.200 0.6157 ns P>0.05

Comparison (Viscosity) Difference q P value

================================== ========== ======= ===========



1/2 and 1/2 vs Pumpkin -1548.3 0.3467 ns P>0.05

Comparison (Diameter) Difference q P value

================================== ========== ======= ===========

Control vs 1/2 and 1/2 -0.6333 4.214 ns P>0.5

Control vs Pumpkin 0.7000 4.657 * P<0.05

1/2 and 1/2 vs Pumpkin 1.333 8.871 ** P<0.01

Pumpkin Control 1/2 and

1/2

6 6.7 7.33

a

b

Comparison (Height) Difference q P value

================================== ========== ======= ===========




0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

TA (g)

Average Texture Analyzer

Control 1/2 and 1/2 Pumpkin

Figure 1: Average force applied to all three variables.

Figure 2: Average viscosity for all three variables.

Figure 3: Average diameter for all three variables.

0

5000

10000

15000

20000

Viscosity (12rpm)

Average Viscosity


0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

Diameter (cm)

Average Diameter


aab

Figure 4: Average height for all three variables.

Subjective Data

Table 7: Average Subjective Data and statistical analysis for Softness

Control 1/2 and

1/2

Pumpkin

Average 3.1 2.6 2.2

Standard

Deviation

2.1 1.2 1.2

0.00

1.00

2.00

3.00

4.00

5.00

6.00

Height (cm)

Average Height


Comparison Difference q P value

================================== ========== ======= ===========




Figure 5: Average ranking of softness. Note: A lower value is considered more desirable.

Table 8: Average Subjective Data and statistical analysis for Moisture

Control 1/2 and

1/2

Pumpkin

Average 3.6 3.4 2.6

Standard

Deviation

1.8 1.2 1.7

0

1

2

3

4

5

6

Softness Ran

king

Average Ranking for Softness



================================== ========== ======= ===========




Figure 6: Average Rankings for moisture of all three variables. Note: A lower value is

considered more desirable.

0

1

2

3

4

5

6

Moisture Ran

king

Average Ranking for Moisture

Control 1/2 and 1/2 pumpkin

Table 9: Average Subjective Data and statistical analysis for Preference

Control 1/2 and

1/2

Pumpkin

Average 3.1 2.6 2.7

Standard

Deviation

1.7 1 1.4


================================== ========== ======= ===========




0

1

2

3

4

5

6

Preference Ran

king

Average Ranking for Preference

Control 1/2 and 1/2 pumpkin

Figure 7: Average ranking for preference. Note: A lower value is considered more

desirable.

Table 10: Average Subjective Data and statistical analysis for Ranking

Control 1/2 and

1/2

Pumpkin

Average 2.1 2.1 1.8

Standard

Deviation

0.9 0.7 0.8


================================== ========== ======= ===========




Figure 8: Average ranking for overall ranking. Note: A lower value is considered more

desirable.

0

0.5

1

1.5

2

2.5

3

3.5

Overall Ran

king

Average Overall Ranking


References:

American Dietetic Association. 2005. Position of the American Dietetic Association: Fat

Replacers. Journal of the American Dietetic Association. 105: 266-275.

Khalil AH. 1998. The influence of carbohydrate-based fat replacers with and without

emulsifiers on the quality characteristics of low fat cake. Plant Foods for Human

Nutrition 52: 299-313.

Lucca PA, Tepper BJ. 1994. Fat replacers and the functionality of fat in foods. Trends in Food

Science and Technology 5(1):12-19.

Min B, Bae IY, Lee HG, Yoo SH, Lee S. 2010. Utilization of pectin-enriched materials from

apple pomace as a fat replace in a model food system. Bioresource Technology.

101(14): 5414-5418.

Palzer S. 2009. Food structures for nutrition, health and wellness. Trends in Food Science and

Technology 20(5):194-200.

Sanchez C, Klopfenstein CF, Walker CE. 1995. Use of carbohydrate-based fat substitutes and

emulsifying agents in reduced-fat shortbread cookies. Cereal Chemistry. 72(1): 25-29.

Voragen AGJ. 1998. Technological aspects of functional food-related carbohydrates. Trends in

Food Science and Technology 9(8-9):328-335.

Weaver C., Daniel J. 2003. Equipment Guide. 2nd ed. Boca Raton: CRC Press. p 107-109, 127-

129.

White JF and others. 1989. Non-digestible fat substitutes of low-caloric value. Patent Number:

4, 861, 613. Grant.

Zoulias E, Oreopoulou V, Kounalaki E. 2002. Effect of fat and sugar replacement on cookie

properties. Journal of the Science of Food and Agriculture. 82(14): 1637-1644.

Appendix:

Sensory Evaluation

Please try all three cupcakes.

Rank the three cupcakes in order of preferance.

302 _______

422 _______

506 ________

Please indicate where each cupcake falls on all three scales. Write the number of each cupcake

above your mark. (There should be three marks on each scale, one for each cupcake.)

Like ExtremelyLike SlightlyDislike Slightly

Dislike

Extremely

Dislike

Moderately

Neither Like or

Dislike

Like Moderately

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Title: The Use of Pumpkin Puree as a Fat Replacement in ... The Use of Pumpkin Puree as a Fat Replacement in Chocolate Cupcakes Abstract: An emerging challenge in the food industry