15% Plantain Flour Vanilla Muffins Preferred Over Control

Transcription

1 15% Plantain Flour Vanilla Muffins Preferred Over Control Nicole Boling, Victoria Horton, and Rachel Stroud 23 November 2009 Food and Nutrition 453 Purdue University

2 15% Plantain Four Vanilla Muffins Preferred Over Control Nicole Boiling, Victoria Horton, Rachel Stroud Abstract Plantain flour contains a high amount of resistant starch, which possesses fiber like qualities that can aid in digestion, blood glucose stability, and other body functions. This experiment sought to explore the possibility of plantain flour substitution for all-purpose white flour in vanilla muffins. The objective of this study was to provide access to more fiber-like compounds in traditional baked goods and test the preference of consumers. A traditional recipe for vanilla muffins was used as the control. Substitutions of 15%, 30%, and 45% plantain flour quantities were variables used for comparison. These varying proportions were baked alike, underwent objective analysis, and were evaluated subjectively by sensory panelists. As plantain flour increased, there were no consistent change in texture, lightness decreased, and volume increased. Sensory panelists preferred the 15% substitution of plantain flour in all categories; including appearance, mouthfeel, texture, and flavor. Therefore, it can be concluded that consumers find a 15% substitution of plantain flour even more palatable than the control. 1. Introduction In 2009, it is projected that $174 billion will be spent on the 8% of the US population struggling with diabetes. This research project began with a desire to look at small changes that could be made to start taking action against these and other outrageous numbers of people struggling to get enough fiber into their diet and maintain blood glucose stability. How could something that everyone already loves be slightly altered to help those struggling with their health? This experiment took a basic muffin, sought to create a healthier alternative, and offered it to panelists in a subjective sensory evaluation. According to an article in Food Chemistry, unripe bananas, widely produced in several Latin American countries, are a source of carbohydrates and nutritionally interesting bioactive compounds. There is an excess of production and large quantities of fruits are lost during commerce, as a consequence of deficient postharvest handling. New economic strategies are considered for banana as a food ingredient (Agama-Acevedo and others 2008). With this in mind, about one-fifth of all banana harvested is wasted and rejected banana are normally disposed improperly. Green banana flour is a low-cost ingredient for food industry and an alternative to minimizing banana wastes (Bello-Perez and others 2009). For this particular

3 experiment, plantain flour will be used due to better accessibility in the United States. Plantain belongs to the family of banana and is popularly called cooking banana, since it is seldom eaten raw (Olaoye and others 2006). Many studies suggest that unripe banana flour exerts many benefits for human health because of its indigestible components and source of antioxidant polyphenols (Agama-Acevedo and others 2008). The high dietary fiber content may protect against bowel cancer via many mechanisms including bulking and laxation and fermentation of fiber to short-chain fatty acids (SCFAs) (Birkett and others 2002). Banana flour exists as a resistant starch which greatly lowers its glycemic index (GI) rating. Considering its benefits, banana flour and plantain flour are contributors to digestive health and helpful for diabetics or any others needing to choose low GI foods. The predominant type of starch found in plantain flour is the resistant starch type 2 (RS2). RS2 are native uncooked granules of some starches, such as those in raw potatoes and green bananas, whose crystallinity makes them scarcely susceptible to hydrolysis (Bello-Perez and others 2009). When compared to commercial wheat flour, higher peak temperature was required to gelatinize the starch of green banana flour despite the similar content of total starch. (Bello-Perez and others, 2009). Both of these chemical properties could pose challenges in our experiment using plantain flour in muffins. Many studies, including the one performed by Agama-Acevedo and fellow researchers, have been performed to examine the effectiveness of using banana and plantain flour in the place of or in addition to regular flour in cooking. In these studies it has shown effective but also reacts differently than usual white flour. Research has also been done on the nutritional benefits of plantain flour, which has concluded that it is indeed a nutritious alternative worth investigating. Little research, however, has been done in the area of preference. While the product has been observed to be a worthy food science investigation and beneficial to human health, little has been said about whether it is something people would actually enjoy eating. The objective of this experiment was to determine the effect (texture, color, volume, and palatability) of plantain flour on vanilla muffins while increasing the nutritional value of the product. The independent variable was the plantain flour content and the dependent variables included texture, volume, color, and palatability from a taste panel. The experiment began with the hypothesis Which plantain flour content will produce the most palatable muffins? and the null hypothesis Substitution of 15%, 30%, and 45% plantain flour will not have an effect on the vanilla muffins texture, volume, color, or palatability. In the course of the experiment specific amounts of plantain flour were substituted for all-purpose white flour and compared to the control (basic recipe with no plantain flour substitution). The area for great variability was in the fact that plantain flour is a resistant starch. This property gives plantain flour the ability to act

4 both as a soluble and insoluble fiber in its ability to steady blood glucose levels and increase insulin sensitivity (Braun 2009). However, it is possible that its resistance could also cause changes in the physical properties and palatability of the control recipe. 2. Materials and Methods 2.1 Materials The materials and measurements used are shown in the following table. Table 1: Muffin ingredients Ingredients English measurement Conversion Metric measurement Flour 2 c. 1 c. flour = 125 g. 250 g. Sugar 1 c. 1 c. sugar = 200 g. 200 g. Baking soda 2 tsp. 1 tsp. = 5 g. 10 g. Salt 1/4 tsp. 1 tsp. = 6 g. 1.5 g. Butter 2 tbsp. 1 tbsp. = 15 ml. 30 ml. Milk 1 c. 1 c. = 240 ml. 240 ml. Egg 1 egg, large 1 large egg=50 g. 50 g. Vanilla Extract 1 1/2 tsp. 1 tsp. = 5 ml. 7.5 ml. 2.2 Preparation For this study, all ingredients were kept constant except for the flour. Plantain flour was substituted at different percentages in place of all purpose white flour. The formulations consisted of 100% all purpose flour and mixtures of plantain:baking flour of 15:85, 30:70 and 45:55 were prepared for the vanilla muffins. In metric measurements this would be 37.5 grams of plantain flour and grams of regular flour, 75 grams of plantain flour and 175 grams of regular flour, and gram of plantain flour and grams of regular flour. 2.3 Procedure The procedure for making vanilla muffins was adopted from the Cooks.com recipe, but adjusted to improve consistency in this experiment. Preheat oven to 200 O C (400 O F). Weigh out all ingredients according to measurements. Mix flour, sugar, baking powder and salt in a large bowl. Melt butter on stovetop or in the microwave. In another bowl mix melted butter, milk, and egg. Beat until mixed well. Mix wet and dry ingredients together. Stir with fork only until all ingredients are moistened. Spoon batter (50 grams + or 5 grams) into paper liners of muffin tins. Bake minutes or until the control muffin is baked completely, to the point where a

5 toothpick can be inserted and removed with no batter sticking to it. Remove from tins immediately (Cooks.com Recipe Finder 2009). The first trial was somewhat difficult since it was the first time the procedure was performed. As the following two trials were performed, the procedure became more natural to complete. 2.4 Texture Analyzer The Stable Micro Texture Analyzer was used to determine the force involved in compression or tension of the muffins. The muffins that were chosen for all of the various objective tests were weighed at 50 grams of batter before baking to ensure consistency between trials and plantain flour amounts. The probe that was used for each analysis was the cylinder probe. The cylinder probe was chosen due to its flat surface, which was the best choice for measuring the compression of the muffins. The Stable Micro Texture Analyzer does not require much interaction. The muffin sample was placed underneath the probe of choice and the test was performed in turn providing the compression results. No replications were performed for each of the trials unless necessary. 2.5 Seed Volume Apparatus The Seed Volume Apparatus was used to determine the volume of muffins for each trial performed, due to its ability to measure irregularly shaped objects such as cakes, bread, or muffins. The apparatus measures the displacement of canola seeds, which is most similar to the principle of water displacement. The muffins that were chosen for this test were all weighed at 50 grams of batter before baking. This was to ensure consistency for comparing the different muffins. 2.6 Hunter Colorimeter The Hunter Colorimeter instrument is used to measure the color of foods. The instrument has three parameters, L (white to black), a (red to green), and b (yellow to blue). This testing was only performed once for each trial of muffins. 2.7 Subjective Palatability Those with a food, dietetic, or scientific background tested the majority of the samples. The samples were cut and placed onto all white paper plates that included the sample number. At least one whole muffin was placed on the sample plate for a visual. The samples were then placed on a table in random order for panelists to evaluate and fill out the following form.

6 Vanilla Muffins Please rank each sample 9-most desirable 1-least desirable Sample # Appearance Mouthfeel Texture Flavor Figure 1: Subjective Panelist Evaluation Form 3. Results 3.1 Volume As seen in Table 2 and 3 as well as Figure 2, the diameter of the baked muffins ranged from 80cm 3 to 155cm 3. The average volumes of the control, 15%, 30%, and 45% plantain flour were 88.3±7.64, 107.7±21.94, 138.3±36.86, and 144.3±12.90 respectively. The 45% plantain flour was the only variable with a volume significantly different from the control (P < 0.05). Table 2: Volume of Baked Muffins from Three Trials Muffin Type Trial 1 Volume (cm 3 ) Trial 2 Volume (cm 3 ) Trial 3 Volume (cm 3 ) Average Volume (cm 3 ) 0% plantain flour % plantain flour 30% plantain flour 45% plantain flour Table 3: Standard Deviation and P-Value of Average Muffin Volume Muffin Type Standard Deviation* of Muffin Volume P-Value** Compared to Control (0%) 0% % % % *Standard deviations are the measurements of variability or distribution of data. **P-Value is the probability that two values equal each other. The chosen value of significance is 0.05.

7 Figure 2: Average Seed Volume for Each Muffin Type 3.2 Color Figure 3 shows that the lightness (L) decreased as the concentration of plantain flour in the muffin increased. In addition to changes in the change in L values, the B value decreases slightly, and the A value increases slightly with increasing plantain flour. As seen in Table 4 and 5, average L, A, and B values respectively are 55.87±4.83, 4.02±3.09, and 18.83±2.34 for the control; 43.63±3.99, 5.69±2.98, and 14.63±1.97 for muffins with 15% plantain flour; 38.05±4.73, 7.00±2.95, and 34.47±0.67 for muffins with 30% plantain flour; and 34.47±5.10, 7.11±2.64, and 12.20±0.71 for muffins with 45% plantain flour. As seen by Table 5, all muffin variables were significantly different from the control in all three colorimeter areas. Table 4: Calorimeter L, A, B Values for Baked Muffins from Three Trials Muffin Type Trial 1 L, A, B Values Trial 2 L, A, B Values Trial 3 L, A, B Values Average L, A, B Values 0% plantain flour 52.06, 7.56, , 2.66, , 1.84, , 4.02, % plantain flour 39.84, 9.11, , 4.29, , 4.70, , 5.69, % plantain flour 45% plantain flour 33.49, 10.33, , 10.15, , 5.97, , 4.70, , 7.00, , 5.74, , 5.43, , 7.11, 12.20

8 Table 5: Standard Deviation and P-Values of Average Colorimeter Data Muffin Type L A B Standard Deviation 0% % % % P-Values 15% % % Figure 3: Average Colorimeter L, A, B values for Each Muffin Variety

9 3.3 Texture Table 6 shows the results of the texture analyzer for the baked muffins, measured in grams of force. The average texture value of the control was 597.9±134.0, 15% plantain flour was 718.6±159.3, 30% plantain flour was 702.1±161.5, and 45% plantain flour was 854.1±535.6, which is shown by Figure 4. Table 6: Texture Analyzer Values for Each Baked Muffin Variety for Three Trials and Average Trial 1 Trial 2 Trial 3 Average of Three Standard P-Value Muffin (g) (g) (g) Trials (g) Deviation (g) 0% % % % Subjective Data Figure 4: Average Texture Analyzer Values for Each Muffin Variety A total of thirty-two semi-trained panelists rated the muffins in areas of appearance, mouthfeel, texture, and flavor using a nine-point hedonic scale (0 being least desirable and 9 being most desirable ). Average results of the subjective data can be seen in Table 7, Table 8 and Figure 5. Appearance, mouthfeel, texture, and flavor respectively were 6.01±2.00, 6.05±1.85, 5.93±1.97, and 5.86±2.22 for the control; 6.99±1.40, 6.37±1.58, 6.43±1.44, and 6.53±1.74 for 15% plantain

10 flour; 6.07±1.65, 6.09±1.68, 6.17±1.64, and 6.38±1.58 for 30% plantain flour; and 5.70±1.93, 5.66±1.94, 5.54±1.59, and 5.53±1.74 for 45% plantain flour. The muffins with 15% plantain flour were rated significantly higher than the control in all areas. The 30% and 45% banana flour results were not significantly different from the control. Table 7: Results of Subjective Data - Muffin Appearance, Mouthfeel, Texture, and Flavor Trial 1 12 Panelists Muffin Type Appearance Mouthfeel Texture Flavor 0% % % % Trial 2 11 Panelists Muffin Type Appearance Mouthfeel Texture Flavor 0% % % % Trial 3 9 Panelists Muffin Type Appearance Mouthfeel Texture Flavor Average from Three Trials 32 Panelists Muffin Type Appearance Mouthfeel Texture Flavor 0% % % % Table 8: Standard Deviation and P-Values of Subjective Results Muffin Appearance Mouthfeel Texture Flavor Standard Deviation

11 0% % % % P-Value 15% % % Figure 5: Average Results of Subjective Data - Appearance, Mouthfeel, Texture, and Flavor for Muffin Varieties 4. Discussion 4.1 Volume As the percentage of plantain flour increased, volume increased, as shown on Figure 2. However, the 15% and 30% plantain flour variables were not significantly larger in volume. Setting the level of significance at P < 0.05, the 45% plantain flour muffin was the only variable

12 to be significantly different from the control. The null hypothesis for muffin volume was Substitution of 15%, 30%, and 45% plantain flour will not have an effect on the vanilla muffins volume. Therefore the null hypothesis can be accepted for 15% and 30% and rejected for 45% plantain flour. It is interesting that adding plantain flour increased the volume of the muffins. Based on previous studies with resistant starch and banana flour, which are very similar to plantain flour, volume decreased with added resistant starch (Baixaulia and others 2007, Agama-Acevedo 2008). The decreased volume in these studies was due to decreased gluten formation. Unlike regular flour, resistant starches do not contain gluten forming proteins. Gluten formation traps air and leads to increased volume. This in turn would to the belief that with increased plantain flour content, volume should decrease. These trials were performed three different times and all provided similar data of increasing volume with increased plantain flour content. Unfortunately, there are no previously performed studies that support our data; therefore more studies should be performed to verify this data. The variation in volume among different trials might be due to measuring equipment errors. Depending on the amount of settling of seeds in the apparatus, the results varied as much as one hundred units. The machine also had a small seed leak that might have contributed to imprecise measurements. In addition, the muffins were covered with plastic wrap, which might have added a varying amount of volume to individual muffins. 4.2 Color The null hypothesis for muffin color was Substitution of 15%, 30%, and 45% plantain flour will not have an effect on the vanilla muffins color. The colorimeter data for all variables was significantly different than the control (P < 0.05). Therefore the null hypothesis can be rejected for all variables. According to the data, plantain flour does have an effect on muffin color. It can be seen from subjective results that the panelists preferred the color of muffins with 15% plantain flour over the control, 30%, and 45% plantain muffins. According to the article, Unripe banana flour as an ingredient to increase the undigestible carbohydrates of pasta the increase in color is due to the reaction of polyphenol oxidase and the phonolic compounds. The reaction produces a brown pigment, resulting in decreased lightness (Agama-Acevedo 2008). Although a dark brown color is undesirable, it is shown later in the subjective results section that a slightly darker muffin (golden brown) is preferred by panelists over a very light-colored muffin (Figure 5). This shows that, although the addition of plantain flour significantly changes baked muffin flour, moderate increases in darkness due to addition of plantain flour might be beneficial to consumer preference. One possible source of error for the data on muffin color is the amount of egg added to the muffin batter. One large egg was assumed to weigh 50 grams. Four eggs were randomly

13 weighed out of their shell to determine the actual weight. The lowest weight was 46.8 grams, the largest weight was 51.6 grams, and the average (mean) weight of the four eggs was grams with a standard deviation of The amount of egg might have contributed to error in the color of the baked product. 4.3 Texture The texture in muffins with 30% plantain flour was significantly different from the control (P < 0.05), while the texture in muffins with 15% or 45% were not. The muffins with 45% plantain flour had a very wide range of values from to grams of force. The variation in texture might be due to the time in the oven. For example, muffins for Trial 1 were placed in the oven for 16 minutes, where the muffins were possibly over-cooked. Trial 2 was taken out two minutes earlier (14 minutes) and the muffins were fully cooked, but noticeably lighter in color and less hard than muffins from Trial 1. While the cook times were consistent for all muffins within each trial, it varied between trials. This could lead to inconsistent trends in muffin texture. In addition, the time between baking and testing the muffins varied between trials. Objective measurements were taken six days after baking muffins for Trials 1 and 2, while measurements were for Trial 3 were taken one day after they were baked. Looking at data from a similar trial, Chemical Composition, Functional and Baking Properties of Wheat-Plantain Composite Flours, it was difficult to compare texture values. The experiment on wheat-plantain composite flour mixtures analyzed texture using break strength, elasticity, and other methods, but not force of compression as used in this experiment (Mepba 2007). Therefore, because of inconsistent trends, possible external variables, and a lack of outside research to compare data, no conclusions can be drawn from this data at this time. 4.4 Subjective Testing As seen by Table 7, 15% plantain flour was preferred over the control in appearance, mouthfeel, texture, and flavor. Table 8 shows that there was a significant difference (P < 0.05) between the 15% and the control, and no significant difference between either 30% or 45% and the control. Therefore the null hypothesis can be accepted for 30% and 45% plantain flour muffins, and it can be rejected for 15% plantain flour muffins. Muffins with 15% plantain flour were preferred by panelists. This is a significant finding in this experiment because it suggests that plantain flour can successfully be added to muffins without decreasing consumer preference. Rather the results indicate that moderate additions of plantain flour might increase consumer acceptability of some products. A source of error in subjective testing might be the color of muffin liners, which varied between trials. For the first trial, the muffin liners were pastel colors. In the second trial, the liners were bright blue. In the third trial, the liners were silver. The color of the muffin liners might have had a slight subconscious effect on consumer preference. In addition, the temperature of muffins varied between trials. The muffins were set out to be tested by semi-

14 trained panelists when they were still warm from the oven. Some panelists might have tested warmer muffins that other panelists depending on how quickly they came to test them. 5. Conclusions The original purpose of this project was to test the possibility of altering a common household treat to be more conducive to quality nutrition. The experiment sought to explore the acceptability of muffins containing different substitutions of plantain flour. This ingredient would provide resistant starch, which acts like a fiber in the digestive system. Objective data results indicate that additions of plantain flour in varying amounts may change physical properties, such as color, texture, and volume. However, according to the subjective data, the substitution of 15% plantain flour was preferred by panelists, even over the control. Further studies should be performed to confirm these results, especially in areas where conclusions could not be drawn or where previous studies proved otherwise, specifically texture analysis. Alternative possible tests could include density differences, oil and water absorption, breaking strength, protein content, etc. This experiment could also be performed with other substitutions such as soy flour, which could also contribute other nutritional benefits. Further research might also explore use of plantain flour in other products such as bread, pancakes, pizza crust, or many other options. 6. References Agama-Acevedo, Edith; Bello-Perez, Luis A.; Goni, Isabel; Ovando-Martinez, Maribel; Sayago- Ayerdi, Sonia Unripe banana flour as an ingredient to increase the undigestible carbohydrates of pasta. Food Chemistry 113(1): Agama-Acevedo E, Islas-Hern JJ, Osorio-Diaz P, Rendon-Villalobos R, Utrilla-Coello, RG, Angulo O, Bello-Perez L Pasta with Unripe Banana Flour: Physical, Texture, and Preference Study. Journal of Food Science. Baixaulia, R., Sanza, T., Salvadora, A., and Fiszman SM Muffins with resistant starch: Baking performance in relation to the rheological properties of the batter. Journal of Cereal Science 47: Bello-Perez LA, Hernandez-Uribe JP, Mendez-Montealvo MGC, Menezes EW, Tadini CC, Tribess TB Thermal properties and resistant starch content of green banana flour (Musa cavendishii) produced at different drying conditions. LWT-Food Science and Technology. 42(4):

15 Birkett A, Jones GP, Lu ZX, Muir JG, O Dea K, Phillips J, Young GP Effect of resistant starch on fecal bulk and fermentation-dependent events in humans. The American Journal of Clinical Nutrition. 62(1): Braun W A New Type of Fiber. The Saturday Evening Post. 281(4): 15 Cooks.com Recipe Finder Vanilla Muffins. Cooks.com Recipe Finder. Mepba, HD, Eboh, L, and Nwaojigwa, SU Chemical Composition, Functional and Baking Properties of Wheat-Plantain Composite Flours. African Journal of Food, Agriculture, Nutrition and Development. 7(1). Olaoye OA, Onilude AA, and Idowu OA Quality Characteristics of Bread Produced From Composite Flours of Wheat Plantain and Soybeans. African Journal of Biotechnology. 5(11):