Table of Contents. Lab #1 Basic Technique and Measurements 2-3. Lab #2 Sensory Evaluation and Product Sampling..3-5

Transcription

1 Table of Contents Lab #1 Basic Technique and Measurements 2-3 Lab #2 Sensory Evaluation and Product Sampling..3-5 Lab #3 Sugar Solutions: Crystalline Candies Lab #4 Starch & Thickening Agents Lab #5 Mystery Fiber Lab #6 Fats and Oils Lab #7 Milk Proteins: Ricotta Cheese Appendix A. Lab #1 Basic Technique and Measurements, data table B. Lab #2 Sensory Evaluation, date tables C. Lab #3 Sugar Solutions: Crystalline Candies, data tables D. Lab #4 Starch & Thickening Agents, data table E. Lab #5 Mystery Fiber, data table and lab key F. Lab #6 Fats and Oils, data table G. Lab #7 Milk Proteins, data table

2 September 7, 2012 Lab #1 Basic Techniques and Measurements Purpose: To observe and practice measuring techniques. Experimental procedures: Measure specified ingredients with measuring cups and weigh ingredients on scale in grams. Each group used measuring cups of 1 cup, ¼ cup, and 1 teaspoon to measure ingredients such as flour, water, brown sugar, white sugar, hydrogenated fat, oil, butter, and salt. They were weighed on a digital scale in grams. The ingredients were measured three separate times in measuring devices and scaled in grams to note the accuracy of measuring techniques. Results: See Appendix A for data table Discussion: This method of running multiple trials and taking the average is used in food science experiments for the expansion of a product and to examine the product potential use in food science. The mean, the arithmetic average of scores, total the data and divide by the number of scores. Despite the fact that the mean is influenced greatly when some data are fat from most of the other scores, it is used frequently because it is the most reliable measure of central tendency (McWilliams, 2008). When measuring flour, I noticed a dramatic variation between sifted and unsifted bread flour and all purpose flour. This demonstrates that when measuring flour, the way you measure may cause changes to a particular product. Measuring ingredients correctly is of key importance. Baking products necessitate very precise measurements, both for liquid and dry ingredients (Foodservice, 2012). When measuring water, the measurements were only vaguely off. I believe this is so because water is a liquid and 2

3 measurements are not as affected with liquids than with dry products. Although, it got a bit tricky when dry ingredients had moisture for instance brown sugar since it is a moist, dense sugar, the trials ranged a bit more when packing the measuring cup. In general the measurements were in close range, but not necessarily precise. With measuring cups, there are many reasons for errors. They are not always accurate since measuring cups evaluate volume not weight. For example, packed versus not packed flour had deviations as it may or may not have empty space. On the other hand, measuring with a scale takes an actual weight, which is more precise than volume and should be used in research rather than measuring cups. Reference: Foodservice Warehouse. (2012). How to correctly measure baking ingredients. Retrieved November 10, McWilliams, M. (2008). Foods: Experimental Perspectives. United States of America: Pearson Education, Inc. 37. September 14, 2012 Lab #2 Sensory Evaluation and Product Sampling Purpose: To experience and evaluate primary tastes and the effect of color on flavor using sensory evaluation tests including: paired comparison, triangle, duo-trio and hedonic scale. Experimental Procedures: Solutions were pre-prepared for participants to taste test. Taste testing was done in silence and participants were told to make an effort not to make facial expressions to not influence each other s assessment of each test. Each participant 3

4 was to read the directions for each series of tests and evaluate the solutions according to these instructions. Participants then compared personal evaluations to actual solutions after the lab was finished. For each series, pour about one to two teaspoons of solution in a small clean cup, taste and evaluate according to the table. Following each taste, eat a piece of bread or drink water to clear your palette. When you have completed the lab, you can evaluate your findings with the actual answers of each solution. Results: See Appendix B for data. Discussion: Series A was the identification of primary tastes, bitter, sour, salt, sweet, and umami. Umami is the taste sensation that enhances savory qualities of flavor but does not have a distinct taste itself (McWilliams, 2008). Series B tested the effect of acid on sweetness. When acid is added to something sweet, the acid increases the sweet flavor. A paired comparison sensory test is a test of difference in which a specific characteristic is designated (McWilliams, 2008). Although, I thought the sucrose and citric acid combination was less sweet than just the sucrose. Series C tested the effect of salt on sweetness through a triangle sensory test, which compares three solutions; two of the solutions are the same and one different. Series D tested the effect of sugar on saltiness in a paired comparison sensory test. Series E tested the effect of sugar on sourness in a paired comparison sensory test. I thought there was no difference between the two, but actually one product was citric acid and sugar while the other was just citric acid. Series F tested the effect of sugar on bitterness using the paired comparison sensory test, in which I thought the less bitter was more bitter and more bitter was less bitter. Series H tested the effect of above threshold levels of salt on sweetness through a duo-trio test. A 4

5 Duo-Trio Test is an overall difference test which will determine whether or not a sensory difference exists between two samples. This method is particularly useful to determine whether product differences result from a change in ingredients, processing, packaging, or storage (The Society of Sensory Professionals, 2010). Series I tested the effect of processing method on the flavor of lemonade by consumer preference hedonic scale sensory test, where we ranked samples in order of preference. I liked the dried lemonade mix the most while the fresh lemonade fell last. The consumer preference hedonic scale sensory test was to give the taster a range in order for the manufacturer to determine to what degree does the consumer life or dislike a particular product. Series J was the effect of color on flavor, this tasting was the same solution, which was lemonade, but in four different colored solutions. I thought yellow, green and blue tasted sour while red tasted sweeter. I was surprised to see the actual answers and I realized that color does play an important role in taste as well. In this experiment the recipes for the solutions were objective whereas the participants evaluations of each series were subjective. After tasting the solutions, I realized drinking water was not getting the taste of solutions out as good as I thought it would. Towards the end after tasting multiple solutions, I felt like I was not making clear decisions on flavors. References: McWilliams, M. (2008). Foods: Experimental Perspectives. United States of America: Pearson Education, Inc. 46, 57. The Society of Sensory Professionals. (2010). Duo-Trio Test. Retrieved November 11,

6 September 21, 2012 Lab #3 Sugar Solutions: Crystalline Candies Purpose: To observe the characteristics and the effects of adding ingredients to sugar solutions when saturated, supersaturated and crystallization. Experimental Procedures: Read all directions and measure all ingredients. Cook on moderate heat and consult Joy of Cooking. Record temperatures and other data assigned to your component. Sample everything and all data is shared. Instead of light cream, use 2/3 cup heavy cream and 1/3 cup half & half and instead of margarine use butter. There were zero vegan caramels. Light Cream Vanilla Caramels: 1 cup + 2 tablespoons of sugar, 1/3 cup brown sugar, 1/3 cup light corn syrup, 2/3 cup light cream, 1 tablespoon butter, 3/16 teaspoon salt, 1 teaspoon vanilla extract. Add all ingredients into pot and mix except for vanilla. Place on moderate heat and lower heat as cooking continues. Stirring occasionally while cooking to end point temperature of 118 C where it should become a firm-ball stage. Add vanilla and turn to into oiled pan. Let caramel cool then cut in 3/5-inch squares. Results: See Appendix C data. Discussion: Cooking vanilla caramel was not as easy as I thought it was going to be. Though we thought we measured the ingredients accurately according to the procedure, the caramel never got to a firm ball stage. We cooked the caramels for about 30 minutes and even though the caramel got thicker it never harden even at 118 C. Since the caramel never hardened, we decided to stick the pan into the refrigerator to let it cool down faster. 6

7 When we took out the pan we were unable to cut the caramels into squares because it was still a bit runny. As a result we had participants use spoons to taste test the product. The product was very sweet, smooth and creamy, but it was not the right consistency for a caramel. One error could have been using measuring cups instead of using the scale. Since the original recipe was given in grams, changing it to volume could have changed the results of the caramel. Caramels are amorphous candies that are noncrystalline candies lacking an organized crystalline structure because of their very high concentration or interfering substances. Other types of noncrystalline candies that were made in this lab were peanut brittle and lollypops. Crystalline candies actually have organized crystalline areas and some liquid trapped inside crystals. Fondant, fudge and divinity are types of crystalline candies that were made in lab. There are saturated solutions and supersaturated solutions. Saturated solutions contain a sugar that is dissolved in heat. When as much sugar has been dissolved into a solution as possible, the solution is said to be saturated (Science of Cooking, 2012). Supersaturated solutions continue to heat so more sugar is being dissolved. It holds a greater number of solutes and is very unstable. An important property of sugar is the hygroscopicity, which is the ability to attract and hold water. It can be useful in maintaining the freshness of some baked products, but can be a source of potential problems in texture when the relative humidity is high (McWilliams, 2008). Discussion questions: A. 7

8 1. Cream of tartar is an acid, which is a sugar stabilizer that promotes inversion of sugar, causing the candy to have a smooth texture. This helps create equal amounts of glucose and fructose. The rate of heat on the sugar solution affects inversion of sugar as well. The more slowly candy simmers, the more inversion that occurs. 2. Cream of tartar can enhance the conversion of the sugar mixtures, while corn syrup is a mixture of starch of maize and contains amounts of maltose. 3. It is important to beat the sugar solution before the sugar solution cools down and the action of beating promotes the formation of small crystalline formation before the solution had cooled too much. The beating stops the formation of large crystals. 4. Cream interferes with crystal aggregation, so the sugar crystals are smaller and give the candy a smoother and fine texture. 5. Cream of tartar is a white powder while the corn syrup is translucent syrup. Products that contain corn syrup can be a bit shinier while products with cream of tartar are more of a dull color. B and C. 1. Milk, cream, chocolate, and egg whites help crystalline candies become smooth by decreasing the size of the crystals. 2. The length of beating and cooking correlates with the formation of crystals. A sugar solution is supersaturated when the beating is continuous and less formation of crystals occurs. 8

9 3. Microwave cooking cooks from the inside out so once the outside is cooked the inside may be overcooked. Stovetop cooking is more evenly distributed and cooked from the outside in. References: McWilliams, M. (2008). Foods: Experimental Perspectives. United States of America: Pearson Education, Inc Science of Cooking. (2012). What is Sugar?. Retrieved November 10, September 28, 2012 Lab #4 Starch & Thickening Agents Purpose: To prepare and observe the results of a variety of thickening agents in food products while observing the effect of sugars and acids on starch viscosity. Experimental Procedures: Each lab group was given a starch to cook in water until it reached gelatinization. After gelatinization continue cooking until the pasting point. After everyone s starch had pasted we observed everyone s starches to determine thickness, transparency and consistency. My group was assigned oat flour, which got thinner and more transparent as we added more sugar. The consistency got better as we added more sugar. Without sugar, the product was lumpy and with sugar it became fairly smooth. The pasting temperature without sugar was 95 C and with sugar was 100 C. After the experiment we froze the finished products to observe one week later the products freeze thaw ability. Results: See Appendix D for data. 9

10 Discussion: Through this lab we saw how thickening agents cause swelling of starches when water is added. The volume of the starch increased which goes into gelatinization. The granules started to swell due to the water and heat. When sugar was added to the starches the products became more translucent. Without sugar, products were thick and reached peak viscosity. After this point, pasting occurred which is when cooking is continued after gelatinization and the granules rupture and collapse inward which becomes gummy and thinner. When viewing the products one week later, there was some error because none of the products thawed fully. We learned that different types of starch display different characteristics in their gelatinization and retrogradation during storage. Sugar delayed gelatinization and competes with the starch for water, resulting in decreased viscosity and more transparency. I found it interesting how different types of starches gelatinized at very different temperatures. Barley flour and buckwheat flour were extremely high which means they had good gel strength and probably higher amylose. As a thickener (as opposed to a gel), it is the amylose that has the main function. The long water-soluble chains increase the viscosity, and that viscosity doesn't change much with temperature (Starch, 2012). Tapioca and potato starch had very low temperatures compared to the other starches, which had high translucency as well. Conclusion Questions 1. The most translucent starches were tapioca and corn starch. 2. Oat flour gelatinized at C. 3. Buckwheat flour, flour, barley flour, and tapioca had the smoothest consistency. 10

11 4. The hygroscopic nature of all types of sugars causes the sugar used in the recipe to compete with the starch for the water needed for gelatinization. This competition partially explains that fact that gelatinization is delayed and the final temperature required to achieve gelatinization is raised (McWilliams, 2008). 5. Sweet rice flour had the greatest freeze-thaw stability. 6. If the product is waxy and does not form a gel than it is mainly amylopectin. Sweet potato and tapioca have the greatest amounts of amylose. References: McWilliams, M. (2008). Foods: Experimental Perspectives. United States of America: Pearson Education, Inc Starch and Modified Starch. (2012). Retrieved November 11, October 5, 2012 Lab #5 Mystery Fiber Purpose: To observe the effects of different fibers in baked goods based on height/cell size, texture and flavor for muffins and spreadability, texture and flavor for cookies. Experimental Procedures: We attempted to make the cookies vegan so the results varied since we used banana puree instead of eggs. A measurement of the mystery fiber was given to us in a bag to put into our mixture. We preheated the oven to 375F on bottom heating, placing the rack in the middle. In a bowl, we mix together the banana puree, sugars, butter, baking soda, salt and vanilla essence with a mixer for two minutes. After, flour was added and mixed again. After, chocolate chips were mixed in. We separated the dough into six equal portions on the baking sheet and baked for 24 minutes. 11

12 Other groups made muffins and cookies with different fibers and data was shared between everyone. After the lab was finish, the mystery fibers were given out. Results: See Appendix E for data. Discussion: Inulin is a prebiotic that is sometimes added to yogurt. It improves flavors with sugar alcohols, and promotes calcium absorption. Dextrins are polysaccharides composed entirely of glucose units linked together and distinguishable from starch by a shorter chain length (McWilliams, 2008). Oat bran is one of a handful of foods that provides significant amounts of both soluble and insoluble fiber. As the oat bran travels through your stomach and into your intestines, the sugar and other nutrients in the grain are absorbed into your bloodstream. The fiber in the oat bran cell walls stays inside your intestines to contribute to your overall health (Keefe, 2011). Flaxseed has several healthy components such as omega 3 s, lignans and soluble and insoluble fiber. 1. Which muffins and cookies had the best texture and flavor? I thought the Oatmeal cookies and Oat Bran muffins had the best flavor and texture. The cookies were chewy and the flavor tasted like chocolate. The muffins were soft and tasted like bread. Both appeared pleasant as well. The cookies were medium height, unlike the other cookies, which were very flat and spreaded fast. The muffins were tall and had a good cell size as well. Two of the cookies tasted burnt to me so could have caused error with those particular fibers. One of those fibers was actually oat bran so that could have changed the results if they did not burn. 2. Which fiber would be the best addition to muffins or cookies to maintain good quality? From the results, I would say Oat Bran. 3. Were you able to guess any of the fiber substitutes? If so, which one(s). 12

13 I was able to guess the flaxseed meal, but that was the only one. Flaxseed has a very distinct taste. References: Keefe, S. (2011). Live strong. How much fiber is in oat bran? Retrieved November 12, McWilliams, M. (2008). Foods: Experimental Perspectives. United States of America: Pearson Education, Inc October 12, 2012 Lab #6 Fats and Oils Purpose: To observe how different sorts of fats can influence the flavor and tenderness of a pastry also how different kinds of flours can affect the flavor and tenderness of a pastry. Experimental Procedures: We mixed ¾ cup of flour and ¼ teaspoon of salt together and added ¼ cup of fat in afterward. We used a pastry blender to cut the fat into the flour until the size of uncooked rice granules. After we sprinkled 2 tablespoons of water over while flipping the mixture with a fork. Then we mashed the dough, flattening it with a rolling pin in to ¼ oblong piece. We cut the dough into strips and baked in the oven for top and bottom heating at 425 F until golden brown. Results: See Appendix F for data. Discussion: From the data collected, shortening turned out the best for flavor and tenderness. The ability of various fats and oils to tenderize a product is determined by their ability to interfere with the development of gluten, the structural protein complex in wheat flour products (McWilliams, 2008). Fats physically prevent gluten development 13

14 by inhibiting contact between water and flour proteins. Shortening is considered plasticity, which means it has the capability to spread. In fact, it can spread over a large surface area to prevent gluten development. Another observation is that whole wheat flour made the least tender pastry out of other types of flours. Whole wheat flour has a higher percentage of protein, which means it has more gluten. More gluten means it will be less tender. One interesting factor was that bread flour was more tender than cake flour. Bread flour has higher protein of 11 to 14% while cake flour is only 7 to 8% (Baking, 2012). However, the cake flour was too soft and it seemed like it was not cooked all the way through. Through this lab, I learned that different types of flours are good for different products. Flours that are higher in protein are more absorbent due to the higher gluten or protein. These flours are great for yeast loaves, buns, and pizza crust. Flours that have less protein form weaker gluten structures and create more tender products such as muffins, cakes and pastries. References: Baking Sciences: Comparing Flours. (2012). Retrieved November 10, McWilliams, M. (2008). Foods: Experimental Perspectives. United States of America: Pearson Education, Inc October 19, 2012 Lab #7 Milk Proteins: Ricotta Cheese Purpose: To observe the reaction between milk proteins combined with the enzymes in rennin. Also to make ricotta cheese with a variety of milks to observe the effects of flavor and tenderness. 14

15 Experimental Procedures: We heated 2 cups of milk in a pot on medium until 83 C. The pot is removed from heat and 1 tablespoon of white vinegar was added, and stirred gently. As curd started to form, we used a colander lined with cheesecloth and placed over a bowl to ladle the curd into the cheesecloth. We made sure to drain the liquid for at least 15 minutes without pressing on the curd. My group used soymilk to make the ricotta cheese. We were surprised to see that a curd did form and that the product came out tender, despite the fact that the taste was not pleasant. Results: See Appendix G for data table. Discussion: This experiment involved making cheese from a variety of dairy milks and then tasting them to determine which products made the best ricotta cheese. We observed the tenderness and taste of the product which is directly correlated with the fat percentage in the product. The higher the fat content in the milk used the better the taste of the cheese. While my group did soymilk, which is about 2% fat, our product came out to be a bit sour and had a bitter aftertaste. Soymilk is not a diary product, but it is used as a beverage by some people who are allergic to milk (McWilliams, 2008). It does not contain the same proteins that dairy milks have, which also could be another factor as to why it was sour. Conclusion questions: 1. Rennin is the proteolytic enzyme in the stomach lining of calves that eliminates the protective function of casein in michelles and results in curd formation (McWilliams, 2008). 2. N/A 15

16 3. Milk whey liquid contributes several minerals to your diet, with differences depending on the milk coagulation process. For example, 1 cup of acid whey provides 250 mg of calcium and 200 mg of phosphorus, or 25 percent of your recommended daily intake of these minerals, while sweet whey gives you only about half this amount (Janine, 2011). Whey also contributes vitamins. A single cup of fluid contributes 30 percent of your daily requirement for riboflavin, 20 percent for both pantothenic acid and vitamin B-12 (Janine, 2011) N/A 6. Whole milk made the best ricotta cheese. Fat content in whole milk certainly played a role in moisture and flavor of the cheese. References: Janine, A. (2011). Live Strong. Nutritional Value of Milk Whey Liquid. Retrieved November 11, McWilliams, M. (2008). Foods: Experimental Perspectives. United States of America: Pearson Education, Inc. 297,