Download The Effects of Adding Varying Amounts of Spinach to Boxed Brownies

The Effects of Adding: 1 The Effects of Adding Varying Amounts of Spinach to
Boxed Brownies
Adam Holley
Jessica Kaag
F&N 453
November 24, 2008
The Effects of Adding: 2 Abstract:
Increasing the nutritional value of traditionally low nutrition foods has many benefits.
The addition of spinach to traditional brownies may lend some answers to different ways that
nutritional foods can be added to such products. In this experiment an attempt was made to
incorporate nutritionally significant amounts of spinach into brownies while not creating changes
in the attributes of flavor, texture, odor, and moisture content. It was found that the addition of
nutritional ingredients is possible, but some changes in preparation and spinach processing may
be required for desirable results.
Introduction:
There is a current trend in America that shows children are consuming less nutritionally
dense foods. This lack of child nutrition is leading to health problems and chronic illnesses
earlier in life than ever before. According to Krebs and colleagues, only 36 percent of children
ages two to nineteen years of age are meeting their daily vegetable requirement of three to five
servings. One of the main nutrients that children are becoming deficient in is iron. This is leading
to anemia which can cause fatigue, loss of concentration, weakness, frequent colds and
infections, and a pale complexion. A child can increase their iron intake by adding iron fortified
cereals, meat, and leafy green vegetables to their diet (Harrar, 2005).
Part of the problem with children's lack of vegetable intake is their dislike for vegetable's
taste and texture. The idea for disguising vegetables in more kid-friendly foods is a strategy to
get children to eat more vegetables. Many children will refuse to eat a serving of spinach, but
will never turn down a brownie. By adding spinach to the brownie recipe, a child can eat a
dessert without knowing that they are actually eating vegetables. According to Bessinger and
The Effects of Adding: 3 colleagues, cannellini beans have been used in a similar manner. The cannellini beans were used
to replace 25%, 50%, and 75% of the fat in the original recipe. After sensory tests using
untrained panelists, it was found that 50% of the fat could be replaced with cannellini beans with
little to no change in texture, taste, and flavor. By replacing 50 percent of the fat with pureed
cannellini beans, the brownies had less fat and more nutrition than with the original recipe.
Increasing your spinach intake can benefit adults as well as children. Spinach is high in many
important nutrients such as vitamin K, vitamin A, manganese, folate, magnesium, iron, vitamin
C, and many other nutrients necessary for human's health and well being. Spinach has even been
shown to reduce risk for certain types of cancer (Esminger, 1986).
Spinach has even been shown to reduce risk for certain types of cancer (Esminger, 1986).
It has been shown to aid in the prevention of ovarian cancer, prostate cancer, and colon cancer.
This is due to the antioxidants found in the spinach. Neoxanthin is a predominate carotenoid in
leafy green vegetables such as spinach. This carateniod has been found to be a powerful
antioxidant. It has been found to prevent the proliferation of prostate cancer cells (Asai 2004).
With the preceding findings in mind, we will be setting the dependent variable as the
quantity of spinach that can be added to brownies and still be undetectable by means of texture
analysis using a Brookfield Texture analyzer, changes in water activity measured by a water
activity meter, and through subjective panel rankings based on taste and moisture.
The main concern with the outcome of this experiment is that the increased water content
from the spinach will negatively affect the texture and overall quality of the brownies. This
problem may be able to be avoided with further experimenting involving various fat content as
well as spinach content. This would have to be tested in a separate experiment to allow for only
one variable.
The Effects of Adding: 4 This experiment will show if there is a possibility to increase the nutritional aspects of
brownies while not sacrificing texture, flavor or moisture qualities typical of a traditional
brownie.
Methods:
The brownies were prepared according to the box specifications and then each batch was
separated into three equal portions. All ingredients were added in whole before dividing the test
batch in to equal thirds. After the division of the batch, spinach was added to two of the thirds in
the quantities of 284 and 369 grams respectively. The recipe in metric units is as follows:
•
595 gram Box Duncan Hines Chewy Fudge Brownie Mix
•
114 grams of egg
•
59.25 mL water
•
109 mL oil
•
0 gram control, 284 grams, or 368.55 grams of Frozen Spinach (thawed and excess
moisture drained off)
•
22.9x12.7x7.6 cm baking pan
Remove the spinach from the freezer. Let it thaw completely. Squeeze out the remaining
moisture in the spinach and then set it aside. Set oven to 177 C. In a large bowl, add brownie
mix, oil, water, egg, and spinach and then mix using a spoon until combined. Spray a
22.9x12.7x7.6 cm baking pan with cooking spray. Pour brownie batter into the pan and spread it
evenly. Place in the pre-heated oven for 36 minutes. Remove them from the oven and then
place on a rack to cool. Once cooled, cut into equal sized samples and served.
The Effects of Adding: 5 The spinach that was used was packaged frozen chopped spinach. Before being added to
the samples, the spinach was defrosted and drained through cheese cloth and the access moisture
was squeezed out. To ensure equal moisture in all samples, the spinach was drained all at one
time in the same batch. This way there was an equal amount of pressure applied and an equal
amount of moisture was removed from all samples. After the addition of the spinach to the two
samples, the samples were placed in separate 22.9x12.7x7.6 cm baking pans. All three samples
were baked simultaneously in the same oven at 177oC rotating positions three times to ensure
that any oven variation is accounted for. The samples spent a total time of 36 minutes in the
oven. This procedure was completed a total of three times to create triplicate test batches for
evaluation.
Once baking was complete for each test batch, the samples were cooled to room
temperature at 25 degrees C. Once at the desired temperature, texture analysis and water activity
tests were completed. The texture analysis was completed using a Brookfield Texture Analyzer.
The machine was equipped with a conical probe at a penetration speed of 0.5 mm per second and
a force of 0.588 N. The texture analysis was undergone to observe any changes that may occur
when spinach was added to the brownies. These changes in texture may be related to moisture
content and the presence of the leafy green to the tested samples. To ensure accuracy, only center
portions of the brownies were analyzed to decrease results representing the hardened edges of the
samples that were closer to the sides of the baking pan. The water activity was taken using a
water activity meter that was calibrated to zero before each test. Water activity was measure to
find the optimum amount of spinach that can be added to the mix without changing the water
activity qualities of a traditional brownie. The water activity will show the changes in available
moisture in each sample of the brownies. To ensure accurate results, it is imperative that all
The Effects of Adding: 6 samples produced were baked for the same amount of time and in the same oven positions.
Subjective results were taken to ensure that the spinach additions did not produce any
exceedingly undesirable flavors or textures. Samples were given using the randomization
method. Each sample was given a random three digit number. From these samples, 50
participants of varying backgrounds were asked to rate the samples texture, flavor, odor, color,
and overall appeal using a nine point hedonic scale. A representation of the sensory scorecard
that was used in our experimentation can be viewed on the following page. Tables three, four and
five show the results from the subjective testing of our samples and the correlating sample
numbers that were presented in the sensory scorecard.
The Effects of Adding: 7 Sensory Evaluation for Brownies
(Please check the box that applies for each sensory attribute (Texture, Flavor, Odor, Color,
and Overall Appearance) for each sample)
Sample 152
Dislike
Extremely
Dislike
Very Much
Dislike
Moderately
Dislike
Slightly
Neither like
nor Dislike
Like
Slightly
Like
Moderately
Like Very
Much
Like
Extremely
Dislike
Very Much
Dislike
Moderately
Dislike
Slightly
Neither like
nor Dislike
Like
Slightly
Like
Moderately
Like Very
Much
Like
Extremely
Dislike
Very Much
Dislike
Moderately
Dislike
Slightly
Neither like
nor Dislike
Like
Slightly
Like
Moderately
Like Very
Much
Like
Extremely
Texture
Flavor
Odor
Color
Overall
Appeal
Sample 653
Dislike
Extremely
Texture
Flavor
Odor
Color
Overall
Appeal
Sample 457
Dislike
Extremely
Texture
Flavor
Odor
Color
Overall
Appeal
The Effects of Adding: 8 Results:
Table 1: The Effect of Quantity of Spinach on the Texture (g) of Box Brownies as
Measured by the Texture Analyzer
Box Brownie Variable
Average (g)
Standard Deviation
Range
Control Box Brownies
33.0
4.5
28.7-37.7
Variable 1- 284 g
Spinach Added
52.3
4.6
47.9-57.1
Variable 2- 369 g
Spinach Added
43.5
11.9
29.9-52.3
Table 2: The Effect of Quantity of Spinach on Water Activity as Measured by the Water
Activity System meter
Box Brownie Variable
Average
Standard Deviation
Range
Control Box Brownies
0.600
0.07
0.546-0.683
Variable 1- 284 g
Spinach Added
0.717
0.01
0.704-0.727
Variable 2- 369 g
Spinach Added
0.833
0.02
0.821-0.851
Table 3: The Sensory Attributes of the Control Box Brownies (Sample 152) as Measured
on a Hedonic Scale with 1 Being the Worst and 9 Being the Best
Sensory Attribute
Average
Standard Deviation
Range
Texture
7.28
1.12
6.0-9.0
Flavor
7.87
1.25
6.0-9.0
Odor
8.10
1.11
5.0-9.0
Color
7.01
1.55
4.0-9.0
Overall
8.02
1.99
6.0-9.0
The Effects of Adding: 9 Table 4: The Sensory Attributes of the Brownie Variable with 284 g Spinach Added
(Sample 653) as Measured on a Hedonic Scale with 1 Being the Worst and 9 Being the Best
Sensory Attribute
Average
Standard Deviation
Range
Texture
4.78
1.98
2.0-6.0
Flavor
5.10
1.11
3.0-8.0
Odor
6.24
2.03
4.0-7.0
Color
6.06
1.25
3.0-7.0
Overall
5.13
1.99
2.0-7.0
Table 5: The Sensory Attributes of the Brownie Variable with 369 g Spinach Added
(Sample 457) as Measured on a Hedonic Scale with 1 Being the Worst and 9 Being the Best
Sensory Attribute
Average
Standard Deviation
Range
Texture
1.75
1.08
1.0-3.0
Flavor
2.83
1.12
1.0-4.0
Odor
4.14
1.75
1.0-6.0
Color
5.04
2.01
1.0-7.0
Overall
2.15
1.75
1.0-5.0
The Effects of Adding: 10 Table 6: Water Activity ANOVA
AW
Between Groups
Within Groups
Total
Sum of
Squares
.081
.011
.093
df
2
6
8
Mean Square
.041
.002
F
21.334
Sig.
.002
Table 7: Texture Analysis ANOVA TA
Sum of
Squares
df
Mean Square
F
Between Groups
559.496
2
279.748
Within Groups
388.107
6
64.684
Total
947.602
8
Sig.
4.325
.069
60
50
Force (g)
40
30
20
10
0
Control
284 g Spinach Added
368 g Spinach Added
Brownie Variation
Figure 1: Average Grams of Force Required for Texture Analyzer to Penetrate Brownies at each Amount of Spinach
The Effects of Adding: 11 0.9
0.8
Water Activity (aw)
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Control
284 g Spinach Added
368 g Spinach Added
Brownie Variation
Figure 2: Average Water Activity Measured in Brownies with Varying Spinach Levels
12
Hedonic Scale Rating (1‐9)
10
8
6
4
Control Brownies
Brownies with 284 g of Spinach
2
Brownies with 369 g Spinach
0
Texture
Flavor
Odor
Color
Overall
Sensory Attributes of Brownies
Figure 3: Average Sensory Attributes of Box Brownies with Varying Levels of Spinach as Measured by Hedonic Scale
The Effects of Adding: 12 Discussion:
The health benefits of adding or increasing leafy green consumption in the daily diet is
well documented and known. The objective of this experiment was to examine the possibility of
masking the health benefits of such leafy green by adding them to well received brownies. With
this tact, the addition of leafy greens to a child’s diet would be greatly increased. In looking at
the effects of the addition of these greens, many attributes were analyzed. The main changes that
were predicted to occur through the addition of spinach, our leafy green of choice, were thought
to be observed in the texture, moisture content and sensory aspects of the brownies.
The health benefits of spinach, when cooked and drained, stem from their being a good
source of Niacin, and a very good source of Dietary Fiber, Protein, Vitamin A, Vitamin C,
Vitamin E (Alpha Tocopherol), Vitamin K, Thiamin, Riboflavin, Vitamin B6, Folate, Calcium,
Iron, Magnesium, Phosphorus, Potassium, Zinc, Copper and Manganese (nutritionData.com,
2008). With the standard serving size of this type of spinach being 180 grams the tested
additions of spinach to the box brownies yield 42 grams of spinach per serving for the 284 g test
and 55 g per serving for the 369 g test or 24% and 30% respectively of the regular spinach
serving size. With this being noted, the amounts of spinach that were added to each sample add
a significant amount of nutrition of a typical serving of brownies.
In looking at the texture attributes of the brownies and how they may be effected by the
addition of spinach in varying amounts, we expected to see no significant difference in the
penetrating forced needed when measuring the brownies using a conical probe affixed to the
Hunter Texture Analyzer. The data that was collected suggests that the most force needed for
penetration was witnessed in the testing of the 284 g sample. The force required for the control
sample was far less than the force required for the samples with the addition of spinach, by an
The Effects of Adding: 13 average of 14.9 g of force. Therefore, there was a significant difference between all test samples
as indicated in Table 6. When the samples were inspected, the causation for the unexpected
texture results became evident. In the preparation of the spinach for this experiment, the chop of
the spinach was large. In this test, the consistency of the spinach in the sample played a large
role in the outcome of the texture analysis. A consideration of future testing would be to
uniformly puree the spinach prior to its addition to the brownies. This application will also show
merit with the analysis of sensory panel data.
The other attribute of the brownies for objective consideration when adding in spinach
was the final product water activity. Analysis of the water activity will show how the addition of
spinach changes the available water in the prepared samples. Some implications of an increase
in water activity are viable in the possibility of a decrease in prepared product shelf life. With an
increase in available water, the possibility of microorganism growth also increases. This
increase in water activity, if observed, can be decreased by a longer baking time or decreasing
the liquids that are added in preparation when spinach is applied to the recipe. As expected,
there was a positive and significant correlation to the amount of spinach that was added and the
water activity of the end products. Because of this increase in the water activity, the moisture of
the brownie was higher which may lead to an increased possibility of microbial growth, staling,
and an overall decrease in the shelf life of the brownie product. After this analysis, omitting the
water required in the recipe when adding the samples should be explored as a possible way of
decreasing the water activity of the final baked product. The lengthening of the baking time was
not recommended due to the possibility of increasing the dryness of the samples on the outside to
ensure that the middle of the samples has had the correct amount of water removed.
The Effects of Adding: 14 Along with mechanical analysis of the samples, subjective testing was observed in the
areas of texture, flavor, odor, color, and overall liking of the samples. All of the samples were
allowed to cool before subjective testing was done. This cooling decreases the spinach odor and
flavor and allows it to be masked by the chocolate in the brownies. The original idea was that the
284 g sample would produce similar results to the control brownies. However, an inverse
relationship was observed between the amount of spinach added to the samples and all of the
sensory evaluation scales. With this in mind, the idea that was previously presented about
decreasing the cut of the spinach to a puree once again becomes a factor. Analysis of the data
shows texture to be least desirable attribute of the spinach added brownies when compared to the
control. The odor, while still an issue, was the most similar attribute when compared to the
control samples. With this being said, another masking technique, in addition to brownie
cooling, would be to add in another flavoring from the leafy green, mint. By decreasing the cut
size to a puree we believe that the texture distaste would be decreased within the subjective tests.
The odor issue can be dampened by the addition of mint as a masking olfaction attribute. We
also believe the addition of mint to the sample would also bolster the flavor profile of the spinach
added samples in the same way it would aid the olfactory sensory data.
The Effects of Adding: 15 References:
Asai A, Terasaki M, Nagao A. An epoxide-furaniod rearrangement of spinach neoxanthin occurs
in the gastrointestinal tract of mice and in vitro: formation and cytostatic activity of
neochrome stereoisomers. Journal of Nutrition. 2004; 134(9):2237-2243.
Bessinger, C., Szafranski, M., and Whittington, J. A., Pureed Cannellini Beans Can Be
Substituted for Shortening in Brownies. Journal of the American Dietetic Association
105(8):1295-1298 (2005).
Ensminger AH, Esminger M. K. J. e. al. Food for Health: A Nutrition Encyclopedia. Clovis,
California: Pegasus Press; 1986. PMID:15210.
Harrar, SarA N., Popeye’s Prescription. Prevention 57(11):127-128 (2005).
Krebs-Smith SM, Ballard-Barbash R, Cleveland LE. Food intakes of US children and
adolescents compared with recommendations. Pediatrics 100(3):323-329 (1997).
NurtitionData: Know What You Eat. 2008. Spinach, cooked, boiled, drained, without salt.
CondeNet Inc. Available from: http://www.nutritiondata.com/facts/vegetables-andvegetable-products/2627/2. Accessed: October 12, 2008.