Black Beans as a Functional Flour Replacer and Protein · PDF fileBlack Beans as a Functional Flour Replacer and Protein and Fiber-Enhancer in Chocolate Cake By: Christine Murzyn,

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 MurzynClaire Riehle

Maura KillianNUTR 453

Formal Written ReportAbstract:

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.



Formal Written Report

Figure 1:

Mechanism of Gluten Reaction in Celiac Disease

- Received from http://www.nature.com/ng/journal/v42/n4/fig_tab/ng0410-281_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,”




(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.



Formal Written ReportMethods:

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




▪ 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



Formal Written ReportSpecial 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.




Figure 3. Subjective testing of the cakes



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

497 309 964 Dislike extremely Dislike very much Dislike moderately

Dislike slightly Neither like or

dislike

Like slightly

Like moderately Like very much Like extremely

Additional comments:



Formal Written ReportResults:

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




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.




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.



Formal Written ReportDiscussion:

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




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.




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, all-purpose 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




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.




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-cake-recipe.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_ALL-PURPOSE_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.

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Black Beans as a Functional Flour Replacer and Protein · PDF fileBlack Beans as a Functional Flour Replacer and Protein and Fiber-Enhancer in Chocolate Cake By: Christine Murzyn,