Black Beans as a Functional Flour Replacer
and Protein and Fiber-Enhancer in Chocolate
Cake
By: Christine Murzyn, Claire Riehle, & Maura Killian
NUTR 453
Formal Written Report
Due Date: December 1, 2014
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Abstract:
Celiac Disease is a disorder that affects a substantial amount of the population. As
such, it is crucial that substitutions must be made in gluten-containing food products to
preserve the health of this subgroup. One potential alteration is the use of black beans as
a flour replacer in chocolate cake. Not only does this substitution allow this product to be
gluten-free, but it also increases the cake’s protein and fiber content. The null hypothesis
states that the replacement of flour by black beans has no effect on the texture, taste, and
coloring of a chocolate cake. Conversely, the alternative hypothesis claims that the
replacement of flour by black beans does have an impact on the texture, taste, and
coloring of a chocolate cake. To test this hypothesis, three trials consisting of baking
three different cakes were completed. One cake had the full amount of flour, one had fifty
percent of the flour replaced by black beans, and the last was a complete replacement of
black beans. After these cakes were baked and cooled at the same time and temperature,
they were evaluated objectively and subjectively for their texture, taste, and color. From
the tests, it was clear that people preferred the control cake overall, but said they liked the
color of the cakes containing beans more than the one without black beans. The objective
tests found that the control cake had the darkest color, followed by the full black bean
cake, then the half black bean cake. These results could be due to unexpected variances in
the baking process. The texture of the cake with the most black beans came out to be the
strongest, followed by the half black bean, then the control. Though the opposite result
was expected, it seemed that the black beans added strong texture to the cakes.
Although the cakes with black beans substituted for flour were less preferable to
the panelists, they are still a good, gluten-free option to those who cannot consume flour.
The black bean-substituted cakes were comparable to the control cake in color, water
activity, and texture. As one of the most common complaints was that the black beans in
the cakes were too large and noticeable, this recipe could be easily improved with using
more finely ground black beans.
Introduction:
In this experiment, black beans were used as a functional flour replacer to create a
gluten-free chocolate cake. The beans also acted to greatly increase fiber and protein
content of the product. Celiac Disease is an immune disorder that affects 0.6% to 1.0% of
the global population (Fasano 2012). Though this amount seems small, it translates to
420,000,000 – 700,000,000 people. As such, this disease is very prominent, with a large
influence on the general public. Its prevalence has spread to developing countries, and
has the ability to impact all individuals, regardless of age, race, ethnicity, and social class.
Fasano (2012) explains that those who suffer from Celiac Disease react poorly to the
consumption of gluten, which is a protein found in items such as wheat, rye, or barley.
When these individuals eat gluten, their immune system produces a “serum autoantibody
response” (Fasano 2012), which can cause irreparable and serious damage to the
intestines. This interaction is shown in Figure 1.
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Figure 1:
Mechanism of
Gluten
Reaction in
Celiac Disease
- Received from http://www.nature.com/ng/journal/v42/n4/fig_tab/ng0410281_F1.html.
This image shows the mechanism of gluten interactions in those with Celiac Disease.
First, the gluten antigen comes into contact with the antigen-presenting cell, which moves
the antigen into an area in which it interacts with a T-cell. This T-cell then signals to the
B-cell to produce antibodies, while simultaneously producing inflammatory cytokines.
Both the autoantibodies and inflammatory cytokines are sent to the intestines, where they
promote inflammation. In turn, this inflammation causes most of the issues and
symptoms associated with Celiac Disease.
The major treatment option offered to those who suffer from Celiac’s is to simply
cease consumption of gluten by adopting an entirely gluten-free diet. While a sufferer
may follow this guideline by completely avoiding all gluten-like products, most
individuals seek out substitutes, such as the black bean cake created in this experiment.
By substituting the flour for black beans, this cake is made gluten-free and thus, is safe
for those who have Celiac’s. As the black beans used in this product greatly increase the
amount of protein present, one does not have to worry about losing the protein-related
benefits of gluten. Regardless, according to Fasano (2012), gluten’s protein content is
low without any superb nutritional benefits, so it can be substituted out of the diet with
little impact to one’s nutritional status.
Unlike gluten, black beans have many nutritional benefits. Legumes are high in
protein. Shuang-kui Du and others (2013), while researching the capabilities of legumes,
found that “The protein content of legume grains range from 17g/100g to 40g/100g,
much higher than that in cereals and approximately equal to the protein content of meat,”
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
(Shuang-kui Du and others 2013). As most of the gluten-containing food products are
similar (though not identical) to cereals, one can assume that substituting black beans in
chocolate cake will result in a “much higher” protein content. Fortunately, increased
protein is not the only asset of black beans.
These legumes also enhance fiber content of the product in which they are placed. In
a study published in Food Chemistry on the effects of substituting different legumes for
wheat tortillas, it was found that, in comparison to the other legumes studied, black and
navy beans contained a, “…higher amount of fiber from the seed coats,” (Anton & others
2008). This signifies that not only are black beans high in fiber, but they are also higher
in this nutrient than many other types of legumes. Anton & others (2008) found that not
only due black beans increase fiber levels, but they also increase antioxidant activity of a
food product. As such, foods containing these legumes are more able to prevent free
radical reactions than those without.
Black beans improve one’s digestive system, due to both fiber and other related
effects. In a study published in the British Journal of Nutrition, researchers found that a
legume-based diet decreases the prevalence of inflammatory cytokines and increases
amounts of anti-inflammatory cytokines (Zhang and others 2014). Pro-inflammatory
cytokines cause inflammation of the intestines, as shown in Figure 1. Not only will the
substitution of legumes for flour decrease gluten-related inflammation, but it will also
reduce inflammation caused by other chemical and physiological factors.
As one can see that black beans possess many unique and essential nutritional
benefits, the purpose of this experiment was to examine whether chocolate cake made
with black beans, rather than flour, is perceived positively by consumers in terms of
color, texture, and flavor. In this experiment, the independent variable refers to the
percentage of black beans supplemented in the place of flour. These percentages are 50%
and 100% (ie. One cup of black beans for one cup of flour, one-half cup of black beans
for one cup of flour). The dependent variable is he effect the substitution has on texture,
taste, and coloring of the cake, and the control variable is a gluten-containing chocolate
cake made entirely with flour. The null hypothesis stated that the replacement of flour by
black beans would have no effect on the texture, taste, and coloring of a chocolate cake.
In order to examine whether the null hypothesis was to be rejected or not rejected,
researchers prepared three chocolate cakes – one control cake with the normal amount of
flour, one flourless cake with half a cup of black beans, and one flourless cake with one
cup of black beans. In three different trials, many subjects sampled each cake, and
completed a sensory scorecard related to texture, color, and taste. Afterwards, researchers
analyzed the cake using a texture analyzer, a Hunter colorimeter, and a water activity
machine. From the results, one can make an assumption on the acceptability of black
beans as a flour replacer in chocolate cake.
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Methods:
Overall Design:
Gluten-free chocolate cakes were baked with the substitution of black beans for
flour. The black beans were low-sodium. During each of the three trials, three cakes
were made: one with the full amount of flour, one with no flour and half the amount of
black beans, and one with no flour and the full amount of black beans. A modified a basic
chocolate cake recipe found from the Food Network website was used (Food Network
2013).
Ingredients for control cake:
▪
▪
▪
▪
▪
▪
▪
▪
▪
▪
165 grams (1 ¼ cups) all-purpose flour
Cooking spray
43.0 grams (1/2 cup) unsweetened cocoa powder (natural or Dutch
process)
200.0 grams (1 cup) sugar
3.45 grams (3/4 teaspoons) baking powder
2.3 grams (1/2 teaspoon) baking soda
3.0 grams (1/2 teaspoon) salt
1 1/2 large eggs, at room temperature
60.0 mL (1/4 cup) vegetable oil
5.0 mL (1 teaspoon) vanilla extract
Ingredients for half black beans cake:
▪
▪
▪
▪
▪
▪
▪
▪
▪
▪
107.5 grams (5/8 cup) black beans
Cooking spray
43.0 grams (1/2 cup) unsweetened cocoa powder (natural or Dutch
process)
200.0 grams (1 cup) sugar
3.45 grams (3/4 teaspoons) baking powder
2.3 grams (1/2 teaspoon) baking soda
3.0 grams (1/2 teaspoon) salt
1 1/2 large eggs, at room temperature
60.0 mL (1/4 cup) vegetable oil
5.0 mL (1 teaspoon) vanilla extract
Ingredients for full black bean substitution:
▪
▪
215 grams (1 ¼ cup) black beans
Cooking spray
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
▪
▪
▪
▪
▪
▪
▪
▪
43.0 grams (1/2 cup) unsweetened cocoa powder (natural or Dutch
process)
200.0 grams (1 cup) sugar
3.45 grams (3/4 teaspoons) baking powder
2.3 grams (1/2 teaspoon) baking soda
3.0 grams (1/2 teaspoon) salt
1 1/2 large eggs, at room temperature
60.0 mL (1/4 cup) vegetable oil
5.0 mL (1 teaspoon) vanilla extract
Procedure:
1. Preheat the oven to 350 degrees F. Coat 9-inch-round cake pans with
cooking spray.
2. Boil 177.0 mL of water. Whisk the cocoa powder and water in a medium
bowl until smooth; set aside.
3. Whisk the flour (control cake only), sugar, baking powder, baking soda
and salt in a large bowl until combined. Add the eggs, vegetable oil, and
vanilla and beat with a mixer on medium speed until smooth, about 1
minute.
4. For cakes with black bean replacement, whisk beans in a separate bowl to
a smooth paste. Add to mixture.
5. Reduce the mixer speed to low; beat in the cocoa mixture in a steady
stream until just combined, then finish mixing with a rubber spatula. (The
batter will be thin.)
6. Pour batter in pan and tap against the counter to help the batter settle.
Bake until a toothpick inserted into the middle comes out clean, about 30
to 40 minutes. Transfer to racks and let cool 10 minutes, then run a knife
around the edge of the pans and turn the cakes out onto the racks to cool
completely. Trim the tops of the cakes with a long serrated knife to make
them level, if desired.
Figure 2. The preparation of the cakes
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Special Precautions:
To control all variables except the independent variable, there were many special
precautions taken when preparing, cooking, and testing the chocolate cake. Because one
trial was done the first week and the next two the second week, the very same ingredients
were used each time, the cakes were baked in the same oven if possible, the baking and
cooling times kept consistent, all the samples served on identical plates with the same
type of fork. The process was the exact same both weeks. When conducting the sensory
evaluation, the three different types of cake were labeled as random 3-digit numbers and
served in equal sizes. The order the three cakes were arranged on the counter was
randomized.
Objective and Subjective Testing:
After the product has been created, it will undergo subjective testing by asking
subjects questions concerning taste, texture, and appearance (see sensory scorecard).
Aspects of the cake will also be objectively analyzed– utilizing the texture analyzer,
water activity machine, and Hunter colorimeter. To test the texture of the chocolate cake,
the Texture Analyzer was used with the following settings: a cone probe, cake setting, a
pre-test speed of 1mm/sec, a test speed of 1mm/sec, a post-test speed of 1mm/sec, a
distance of penetration of 3mm, and a trigger force of 1 gram. One sample of each cake
was tested three times on the texture analyzer. To test the moisture content, also relating
to the texture aspect of the chocolate cake, the Aqualab Water Activity System Meter
CX-2 was used. One sample of each cake was tested three times with this machine. To
determine the color changes between each type of cake, the Hunter Colormeter tested one
sample of each cake three times and generated a L, a, and b value for each test. Since a
machine could not be used to rate the taste of each cake, 6-12 subjects tasted the samples
and rated them on a hedonic scale. They also rated their preference for color and texture
on a hedonic scale.
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Figure 3. Subjective testing of the cakes
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Sensory Evaluation
Texture
On a scale of 1(thin, flimsy, soft) to 3 (tough, hard, thick), rank the texture of the
chocolate cake
_____ 497
_____309
_____964
Color
Rate the samples from lightest color to darkest
Lightest ____________
____________
Darkest ____________
Taste
497
Dislike extremely
Dislike very much
Dislike moderately
Dislike slightly
Neither like or
dislike
Like slightly
Like moderately
Like very much
Like extremely
Additional comments:
309
964
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Results:
Subjective Analysis:
Figure 4- Effect of Black Beans on Texture. Scale (1-3): 1=thin, flimsy, soft; 3=tough,
hard, thick.
Figure 5- Effect of Black Beans on Color. Scale (1-3): 1= lightest; 3= darkest
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Figure 6- Effect of Black Beans on Consumer Preference. Scale (1-9): 1= dislike
extremely; 9= like extremely
Objective Analysis:
Figure 7- Effect of Black Beans on Texture. Measured by Texture Analyzer.
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Figure 8- Effect of Black Beans on Color. Measured by Hunter Colorimeter.
Figure 9- Effect of Black Beans on Aw. Measured by Water Activity Meter.
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Discussion:
While the null hypothesis for this experiment stated that the utilization of black
beans as a flour substitute for chocolate cake would have no impact on the texture, flavor,
and color of the cake, the alternative hypothesis claimed that the alteration would result
in a change in texture, taste, and coloring of the cake. For the most part, the findings
obtained from this experiment support the alternative hypothesis and reject the null
hypothesis.
Many of the results received in these trials have been obtained in prior research
conducted on legume substitutions. In fact, results were very similar to those findings
obtained from Rankin and Bingham (2000) from an experiment involving substitution of
fat by black beans. Rankin and Bingham explained, “For overall acceptability and
appearance, color, flavor, and texture, there were significant differences based on the
amount of beans that were substituted” (Rankin & Bingham 2000). These researchers
found that the relationship between palatability of cookies and amount of beans
substituted was statistically significant. The use of beans as a fat substitute negatively
impacted the group’s hedonic ratings (Rankin and Bingham 2000). Similarly, in the
experiment explained in this lab report (Figure 6), the substitution of flour by black beans
resulted in lower hedonic scores, for both the half and full-substitutions. Like the work
conducted by Rankin and Bingham (2000), there were significant taste differences
between all three products made in this experiment.
Contrarily, in the subjective analyses of both texture and color of the chocolate
cake, while the control results were significantly different than those of the black bean
cakes, the latter two products did not receive statistically significant differences. In
regards to texture in Figure 4, panelists asserted that the fully-substituted cake was the
least tough, while the control cake was the most tough. According to Anton and others
(2008), as bean products are added to a sample, the sample should decrease in firmness.
This is congruent with the results obtained in the subjective analysis.
When analyzing color in Figure 5, panelists claimed the control cake to be of the
lightest color, and the two black bean-substituted cakes to be similarly dark in control.
According to Anton and others (2008), in an experiment analyzing the impact different
legume flours have on the properties of a tortilla, the use of the black bean-based flour
resulted in the largest color difference of all legume-based flours used, when in
comparison to the color of control, wheat tortilla. This dark color is due to the dark
pigments of this specific legume. As such, the results of Anton and others’ experiment
correspond with those explained in this subjective assessment. The objective analysis of
color (Figure 8) obtained similar results, in which the differences in color of all three
samples were all significant. This signifies that the use of black beans has a major impact
on the color of the cake.
After utilizing the Texture Analyzer on samples of cake for an objective analysis,
it was found in Figure 7 that the fully-substituted cake was the toughest, and the control
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
cake was the weakest. Overall, the texture differences of all three cakes were statistically
significant. Anton and others’ (2008) analysis of texture is somewhat congruent with the
work displayed in this lab report. According to researchers, “Addition of bean flour,
regardless of cultivar or concentration, significantly affected firmness [of product],”
(Anton and others, 2008). However, unlike in Anton and other’s trials, in the case of this
experiment, substitution of flour for black beans increased firmness of the product, shown
by high force readings on the Texture Analyzer. It is important to note that consumer
panelists scored the control cake as the sample being the most tough. This discrepancy
will be discussed later, as it was predicted that the control should have been the firmest
sample.
Through objective assessment of the water activity of the cakes created in the
aforementioned experiment, it was found that though the fully substituted cake possessed
the highest water activity, none of the cakes had any statistically significant differences in
this characteristic. When they substituted bean flours for wheat flours in tortilla products,
Anton and others (2008) found that those foods made with the legume flour possessed a
higher water absorbing capacity. Though this is not the same concept as water activity, it
measures moistness in a similar fashion. As such, an increase in water absorbing capacity
is often correlated with an increase in water activity. As one can see from Figure 9, when
the full substitution of black beans (1 ¼ cup) was made for flour, the modification
resulted in higher water activity. Though the difference in water activity among the
control and full substitution was not significant, it is still in line with the work published
in Food Chemistry. However, because the differences in water activity in this experiment
are not significant, it implies there may not be any significant changes in shelf stability or
spoilage in the control cake versus the black bean cakes. In a similar study, Du and others
(2014) found that use of black bean flour results in very high oil absorbing capacity as
well. Though not analyzed in the chocolate cake experiment, prior research conducted in
the same area discovered other significant quality changes in bakery products made with
the aid of black beans. For example, Anton and others (2008) asserted that use of this
legume flour resulted in low dough stability and consistency. Similarly, Siddiqu and
others (2010) asserted that use of this legume led to a low bulk density, a low viscosity,
and low foaming and emulsion capabilities. Overall, most of these characteristic changes
are not beneficial. However, the use of black beans in bakery products does lead to
positive results.
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Figure 7. From left to right: Control cake, 50% black bean replaced cake, 100% black bean replaced cake
Overall, the substitution of black beans increased both the protein and fiber
content within the cake. While the dietary fiber content of 1 ¼ cup of enriched, allpurpose flour is 5 g, the dietary fiber content of 1 ¼ cup of low-sodium, black beans is
18.75g (USDA, 2012). This is almost four times as much protein as the control. The
protein content of the control cake was 15 g. The completely substituted black bean cake
- 1 ¼ cup black beans - was 19.05 g, about four grams higher than that of the control
(USDA, 2012). Though the half-black bean batch (⅝ cup) contained a lower protein
content than that of the control (9.525 g and 15 g, respectively), it still contained almost
double the fiber content. While the control only had a fiber level of 5 g, the half-black
bean batch had a level of 9.375 g (USDA, 2012). After substitution of black beans for
flour, the fiber content increased substantially for both the full and half-legume
substitutions. The full substitution resulted in a higher protein content as well, signifying
that this modification not only creates a gluten-free product, but also a product with
enhanced protein and fiber benefits.
Potential sources of error that resulted from this experiment could have occurred
because we had to use different ovens out of the sake of time although we had not
planned to do so. The use of multiple ovens for the various trials could have affected the
texture and moisture content of the chocolate cake. Since most of the class finished after
the first laboratory period, there were a lot less subjects and a completely different pool
available to do a sensory evaluation for the second and third trial. Since the sensory
panelists took samples of the cake before the objective test were performed, there was a
limited amount of cake to test. Consequently, the objectively tested samples came from
varying parts of the cake; some came from the middle and some from the crust area. This
discrepancy could have created another unwanted variable in our measurements. One last
source of error was the differing texture results from the objective and subjective tests.
While the subjective analysis concluded that the control cake was the most tough, the
objective assessment concluded that the fully substituted cake was the most tough. One
potential cause for this discrepancy may have been a misunderstanding between to
scorecard directions and the consumer panelists. However, a more likely cause
inconsistent testing of the cake (ie. testing the crust rather than the middle of the cake, or
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
vice versa). This signifies that the consumers may have sampled different parts of the
cake than that which was analyzed in the Texture Analyzer, which would lead to
incorrect results.
If this experiment was to be conducted a subsequent time, multiple suggestions
for future work may aid in the betterment of this study design. One recommendation
includes analyzing different volumes of black beans (acting as a substitute) to find the
optimal legume content. For example, rather than simply substituting ½ cup and 1 cup of
beans for 1 cup of flour, future researchers should attempt to substitute more volumes as
well, such as ¼ cup, ⅓ cup, ⅔ cup, and ¾ cup. Also, experimenters should ground the
black beans into a finer consistency, attempting to make it as powder-like as possible.
This may improve consumer perceptions of texture, and could result in texture analyzer
readings closer to that of the control. Researchers should make certain that only a specific
area of the cake is assessed. For example, when preparing samples for both objective and
subjective analysis, they should use only the crust or only the middle of the cake. This
will allow for more consistent readings. A fourth suggestion includes using the same
pool of subjects to ensure consistent consumer perception results. Another
recommendation is the repeat the experiment step-for-step, but to try it with a different
time of legume, such as chickpeas or kidney beans. The type of legume has the ability to
influence many aspects of both the objective and subjective results. Lastly, future
experimenters should attempt to alter the black bean to liquid ratio within the recipe, and
analyze how this impacts consumer perceptions and water activity readings.
Christine Murzyn
Claire Riehle
Maura Killian
NUTR 453
Formal Written Report
Works Cited:
Anton, A, & others. 2008. Influence of added bean flour (Phaseolus vulgaris L.) on some
physical and nutritional properties of wheat flour tortillas. Food Chemistry 109: 33-41.
Du, S, Jiang, H, Yu, X, & Jane, J. 2013. Physicochemical and functional properties of
whole legume flour. LWT – Food Science and Technology 55: 308-313.
Fasano, A & Catassi, C. 2012. Celiac Disease. N Engl J Med 375 (25): 2419-2426.
Food Network. 2013. Basic Chocolate Cake. Available from:
http://www.foodnetwork.com/recipes/food-network-kitchens/basic-chocolate-cakerecipe.html. Accessed 2014 September 23.
Rankin, LL & Bingham, M. 2000. Acceptability of oatmeal chocolate chip cookies
prepared using pureed white beans as a fat ingredient substitute. J Am Diet Assoc 100
(7): 831-833.
Siddiq, M., Ravi, R., Harte, J.B., & Dolan, K.D. 2010. Physical and functional
characteristics of selected dry bean (Phaseolus vulgaris L.) flours. LWT - Food Science
and Technology 43: 232-237.
USDA. 2012. Household USDA Foods Fact Sheet. Flour, all-purpose, enriched.
Available from: http://www.fns.usda.gov/sites/default/files/HHFS_FLOUR_ALLPURPOSE_100400November2012.pdf. Accessed 2014 November 23.
USDA. 2012. Household USDA Foods Fact Sheet. Beans, black, low-sodium, canned.
Available from:
http://www.fns.usda.gov/sites/default/files/HHFS_BEANS_BLACK_110020aug2012.pdf
. Accessed 2014 November 23.
Zhang & others. 2014. Cooked navy and black bean diets improve biomarkers of colon
health and reduce inflammation during colitis. Br J Nutr 111: 1549-1563.