The expansion of dough Essay Example for Free

The expansion of dough Essay There are many factors that may have an effect on the expansion of dough but I will research temperature and material, the experiment is as follows. 25g of flour will be weighed into a beaker, and sugar will then be added. 30cm3 of yeast suspension will be measured in the 50cm3 measuring cylinder, and then added to the flour and sugar. It will then be stirred until a smooth paste. The paste will then be poured into the 250cm3 measuring cylinder without touching the sides. This is a precaution, because otherwise there will not be the correct amount of paste. The volume of the paste in the measuring cylinder will be recorded and the cylinder will be placed in one of the waterbaths, the temperature noted. The clock will be started and the volume recorded every 2mins for about 30mins. I think this experiment will work because dough is known to rise when heated I think that the higher the temperature, the bigger the expansion and if left over a period of time, at the same temperature, it will increase further, until a certain point. I believe this, because yeast is made up of a single-celled organism, Saccharomyces cerevisiae, which multiplies rapidly when fed sugar and the yeast will convert starch to glucose, a simple sugar. This ferments the sugar, which converts to alcohol and carbon dioxide. The carbon dioxide gas helps raise the dough and the dough rapidly expands, increasing in volume. To support my hypothesis further I had to research, I found the following sites and books helpful: http://encarta. msn. co. uk/find/Concise. asp? z=1pg=2ti=761556236 http://homecooking. about. com/library/weekly/aa072197b. htm Biology for AQA separate award by Ann Fullick. I have performed the experiment using the method mentioned previously. I have paid attention to the precautions carefully, and tried to do it correctly and as precise as possible and have obtained the following results: Time (mins) Volume (cm3) Temp: 22i C-glass Temp: 32i C-plastic Temp: 32iThe results shown in the table prove that the higher the temperature, the further the dough will rise, supporting my hypothesis. To support my hypothesis further I had to research, I found the following sites and books helpful: http://encarta. msn. co. uk/find/Concise. asp? z=1pg=2ti=761556236 http://homecooking. about. com/library/weekly/aa072197b. htm Biology for AQA separate award by Ann Fullick The graph, on the next page, shows that when dough is heated at a higher temperature it will rise faster. However, if heated in a glass-measuring cylinder, it would have perhaps risen further than it did. This can be seen by comparing the dough at 32i C in the plastic measuring cylinder (A) and the dough at 22i C in the glass-measuring cylinder (B). Although A is 10iC above B for the first fourteen minutes, they are constantly crossing temperatures. As line of best fit, starts lower than B, its intercept being 23 and Bs being 32. From the graph, the differences between the lines can be seen easily, at 37i C, it had risen the most and at 22i C, it had risen the least, the difference between the two being 46 cm3. At 22i C, it raised 28cm3, at 32i C it raised 44cm3, and at 37i C it raised 74cm3, and the graph showed this. From the line of best fit, the lines can be compared by their intercepts and gradients easily. However, the line which each set of results form is more important.Each of them show a steady rise, but the steadiest is the dough at 37i C, this suggest that perhaps this is an ideal temperature for rising dough, not too high as to kill the yeast and not too low, so it wont grow as fast and as steady. This also helps me to understand why a change in material will help the dough rise faster or slower. If in a glass container, the heat can pass through easily, and so it will rise faster, but because plastic is an insulator, the heat cannot pass through as easily. In conclusion, I can form the opinion that dough will expand more rapidly when at a higher temperature, perhaps ranging between 30iand 40i , and in a container that is not heat resistant, and the graph shows this in a simpler form. I think this because yeast multiplies at a faster rate in a high heat, however, if too high, it will die. Also, the graph shows the dough rising at a steady rate at 37i C, and so at 40i C it would perhaps rise faster, and it raises relatively well at 32i C. Although the yeast would probably rise faster in a higher heat, within bread the carbon dioxide gas given off would probably create pockets within the bread, or the yeast would begin to die. The results have turned out as expected, supporting my prediction. My method gave evidence that was reliable, and so would be counted on as correct. I believe this because it showed how yeast can be useful and expands dough in higher temperatures. By producing dough and exposing it to the conditions in which I wanted to test it, I could produce reliable results. This was done by measuring the dough carefully and fairly, using the same ingredients as a precaution, making the investigation fair; and then heating it at a steady temperature. By recording it throughout, I was able to produce a graph, to show my results in a clear and precise way. I think that I have given enough evidence to draw a conclusion. However, I think that this investigation could be advanced, by heating dough at a lower temperature, such as 15i C, in two different materials, and then the same again at a higher temperature, such as 50i C, also at a middle temperature, such as 18i C. By comparing two extremes and an intermediate, we can see if yeast will rise any more rapidly and steadily at the different temperatures and more importantly, if the materials in which they are heated make a difference. This would help support my earlier conclusion, that dough will expand more rapidly when at a higher temperature, perhaps ranging between 30i and 40i , and in a container that is not heat resistant. Investigation to observe the effect of temperature on the expansion of dough Dominique Briggs 10y Biology Mrs Tottey Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Patterns of Behaviour section.