The Effect of Whole Wheat Flour on Banana Bread

Transcription

1 The Effect of Whole Wheat Flour on Banana Bread Kathryn Slaboski F&N November 9,

2 Abstract: Eating a diet rich in whole grains has proven to reduce the risks of heart disease, diabetes, and obesity, among other chronic diseases. The majority of Americans, however, do not consume a sufficient amount of whole grains in their daily diet. In this experiment banana bread was made with three different variables: one recipe used allpurpose flour, one used half all-purpose and half whole wheat flour, and one used only whole wheat flour. Each product went through three trials of testing for texture, volume, and palatability. Texture was measured with a Texture Analyzer, volume with a Seed Volume Apparatus, and palatability with a Hedonic Ranking Scale. The results reveal that the banana bread made with half of each type of flour provides a good balance of aesthetic and nutritional benefits. Introduction: Health experts advise everyone of every age and gender that grains are a healthy necessity in every diet, and that it's important to make at least half our grains whole grains. Eating whole grains has been shown to reduce the risks of heart disease, stroke, cancer, diabetes, and obesity ( Reaping the Benefits, ). A whole grain is the natural state of the grain; it includes the bran, the germ, and the endosperm. When a grain is refined, the bran and germ are removed, leaving only the endosperm. The bran contains important antioxidants, as well as B vitamins and fiber; and the germ provides protein, minerals, healthy fats, and many B vitamins (Liyana-Pathirana, Chandrika, and Shahidi, ). With the bran and germ removed, the grain loses about % of its protein and at least key nutrients. Whole grains are much healthier, providing more protein, more fiber, and many important vitamins and minerals, such as B vitamins, vitamin E, folic acid, calcium, zinc, iron, manganese, and magnesium (Lebiedzińska & Szefer, ). Whole grains offer a variety of numerous health benefits. The high fiber levels in whole grains help fight obesity and metabolic syndrome. Additionally, fiber levels along with the phytochemicals and antioxidants found in whole grains help to reduce the risk of cancer, stroke, and heart disease (Tsang, ). The high levels of magnesium in whole grains help reduce the risk of type diabetes, since magnesium acts as a co-factor for enzymes involved in the body s secretion of glucose and insulin ( Whole Wheat, ). In January of, the United States government published its new Dietary Guidelines for Americans. These guidelines recommended that all adults eat at least half of their grains as whole grains, resulting in about servings of whole grains per day. Americans, however, average less than one serving of whole grains per day. In fact, more than % of adults in the United States typically consume no whole grains at all ( Five New Reasons, ). One of the main reasons for the popularity of wheat flour is due to its glutenforming capacity when the flour is mixed with liquid. Gluten is the substance that provides strength and elasticity to dough and is responsible for the leavening ability of baked goods. The more protein in the wheat flour, the more gluten that is formed when the flour is mixed with liquid ( Types of Wheat Flour, ). All-purpose flour is the most commonly used wheat flour for general baking and cooking. It is produced from a combination of bread flour, milled from a variety of hard wheat, and cake flour, milled from a variety of soft wheat. Bread flour contains high levels of protein, and therefore,

3 high levels of gluten; while, cake flour contains low levels of protein and gluten. This combination gives all-purpose flour just the right balance for most baked goods ( Types of Wheat Flour, ). Whole wheat flour is produced by grinding the full kernel. Used alone in bread making, whole wheat flour results in a nutritious, but smaller and denser product. This density and reduced volume is due to the bran, which hinders the dough from rising fully. In order to produce a bread loaf that is somewhat lighter and of greater volume, it is often best to combine whole wheat flour with all-purpose flour ( Types of Wheat Flour, ). The purpose of this experiment is to implement whole grains into a commonly consumed product, while maintaining desirable texture and palatability. Methods: The recipe that was used as the control in this experiment is from Allrecipes.com. It was cut in half, and reads as follows: Ingredients: g all-purpose flour 8. g brown sugar. g baking soda egg, beaten. g salt bananas, mashed, overripe. g butter Preheat oven to degrees F ( degrees C). Lightly grease a x loaf pan. In a large bowl, combine flour, baking soda, and salt. In a separate bowl, cream together butter and brown sugar. Stir in egg and mashed bananas until well blended. Stir banana mixture into flour mixture; stir just to moisten. Pour batter into prepared loaf pan. Bake in preheated oven for to minutes, until a toothpick inserted into center of the loaf comes out clean. Let bread cool in pan for minutes, then turn out onto wire rack. For the second variable, follow the same procedure as above, except use. g allpurpose flour and g whole wheat flour. (All-purpose flour is slightly heavier than whole wheat flour.) And for the third variable, follow the control procedure except use g of whole wheat flour instead of all-purpose flour. After all products were made, they were measured for texture, volume, and palatability. Texture measurements were taken with the Texture Analyzer, and volume was measured with the Seed Volume Apparatus. The Texture Analyzer utilized in this experiment featured the puncture probe. A Hedonic Ranking Scale was used to evaluate consumer taste preference. This subjective test was given before a semi-trained panel and appeared as follows:

4 Extremely Very Much Moderately Slightly Neither nor Slightly Moderately Very Much Extremely Such a table was presented in front of each of the three samples, and panelists were asked to mark below the statement that they agreed with. Each sample was assigned an arbitrary number: the all-purpose flour sample was #8, the half all-purpose and half whole wheat flour sample was #9, and the whole wheat flour sample was #9. The test was randomized in that the samples were given in a different order each time. Discussion: The results from the texture analyzer showed that the whole wheat flour yielded a product of denser texture. The greater breaking force of the banana bread made with whole wheat flour is due to the higher protein content of the flour. This makes the product more dense (Bonafaccia, ). In trial the grams of force required to penetrate the banana bread made with whole wheat flour was slightly less than the grams of force required for the bread made with half whole wheat and half all-purpose flour. The source of error for this experiment may stem from the cooking time. The half & half bread baked a few minutes longer than it should have for trial. The overcooked top may have caused the increase in required grams of force. The results from the seed volume apparatus are congruent with research findings. Literature sources indicate that bread made from whole wheat flour will yield a denser product. This density and reduced volume is due to the bran, which hinders the dough from rising fully. In order to produce a bread loaf that is somewhat lighter and of greater volume, it is often best to combine whole wheat flour with all-purpose flour ( Types of Wheat Flour, ). These properties are demonstrated in Figures,, and in the following section. The results from the palatability tests are fairly consistent. As shown in Figures -, the banana bread made with all-purpose flour has the highest palatability rankings. The banana bread made with half and half demonstrates palatability rankings only slightly lower than those of all-purpose flour. The rankings for banana bread made with whole wheat flour are markedly lower than all-purpose flour. These results prove that, while a product made purely with whole grains is the most nutritionally beneficial, a banana bread product made with half all-purpose flour and half whole wheat flour is both aesthetically and nutritionally pleasing.

5 Results: Table : Effect of Whole Wheat Flour on Breaking Force as Measured by the Texture Analyzer Trial Trial Trial #8 (all-purpose). g 9. g.8 g #9 (half & half). g. g 8. g #9 (whole wheat). g 8. g. g Table : Effect of Whole Wheat Flour on Volume as Measured by the Seed Volume Apparatus Trial Trial Trial #8 (all-purpose) cm cm cm #9 (half & half) 9 cm cm cm #9 (whole wheat) cm 9 cm cm Table : Effect of Whole Wheat Flour on Palatability Extremely Very Much Moderately Slightly Neither nor Slightly Moderately Very Much Trial #8 #9 #9 Trial #8 #9 8 #9 Trial #8 #9 #9 Extremely

6 For the following figures: The y-axis is the grams of force. On the x-axis, = banana bread made with all-purpose flour, = half of each type of flour, and = whole wheat flour. Trial : 8 8 Figure : Breaking Force Increases with Addition of Whole Wheat Flour Trial : 8 Figure : Breaking Force Increases with Addition of Whole Wheat Flour

7 Trial : Figure : Breaking Force Increases with Addition of Whole Wheat Flour For the following figures: The y-axis is volume measured in cm. On the x-axis, = banana bread made with all-purpose flour, = half of each type of flour, and = whole wheat flour. Trial 8 8 Figure : Volume Decreases with Addition of Whole Wheat Flour

8 Trial 9 8 Figure : Volume Decreases with Addition of Whole Wheat Flour Trial 8 Figure : Volume Decreases with Addition of Whole Wheat Flour

9 For the following 9 figures: The y-axis represents the number of people who responded a certain way. On the x-axis, = Extremely, = Very Much, = Moderately, = Slightly, = Neither nor, = Slightly, = Moderately, 8 = Very Much, and 9 = Extremely Trial 8 9 Figure : Palatability is High for All-Purpose Flour Trial 8 9 Figure 8: Palatability is High for All-Purpose Flour

10 Trial Figure 9: Palatability is High for All-Purpose Flour Trial 8 9 Figure : Palatability is Slightly Lower for Half All-Purpose and Half Whole Wheat Flour

11 Trial Figure : Palatability is Slightly Lower for Half All-Purpose and Half Whole Wheat Flour Trial 8 9 Figure : Palatability is Slightly Lower for Half All-Purpose and Half Whole Wheat Flour

12 Trial 8 9 Figure : Palatability is Low for Whole Wheat Flour Trial Figure : Palatability is Low for Whole Wheat Flour

13 Trial Figure : Palatability is Low for Whole Wheat Flour References: (). Five New Reasons to Get Whole Grains. Food Chemistry (), -. Retrieved September 8,, from Science Direct database. (). Reaping the Benefits of Whole Grains. Whole Grains Council. Retrieved September,. Web site: Guide.html (). Types of Wheat Flour. Retrieved September,. Web site: recipetips.com/kitchen-tips/t--/types-of-wheat-flour.asp (). Whole Wheat. The World s Healthiest Foods. Retrieved September,. Web site: healthbenefits Albeluhn, Shelley. (). Banana Banana Bread. Retrieved September,. Web site: Recipe/Banana-Banana-Bread/Detail.aspx Bonafaccia, G. & Galli, V. (). Characteristics of spelt wheat products and nutritional value of spelt wheat-based bread. Food Chemistry 8(), -. Retrieved September 8,, from Science Direct database.

14 Lebiedzińska, A. & Szefer, P. (). Vitamins B in grain and cereal grain food, soyproducts and seeds. Food Chemistry 9(), -. Retrieved September 8,, from Science Direct database. Liyana-Pathirana, Chandrika M. & Shahidi, Fereidoon. (). Antioxidant and free radical scavenging activities of whole wheat and milling fractions. Food Chemistry (),. Retrieved September 8,, from Science Direct database. Tsang, Gloria, R.D. (). The Whole Truth about Whole Grains: Whole Grains Guide. Retrieved September 8,. Web site: whole-grains.shtml