Technology: Leavening Process
Leavening is a substances that is used to ensure rising or alternatively fermentation occurs in grain products. Therefore the leavening process is purely based on knowledge of how best to retain gas within flour products or grain products for an acceptable amount of time. There are several factors which are involved and determine the level of gas retention in dough which include; applied yeast, sugar and salt concentration, amount of temperature involved in baking and the time duration taken in baking the dough products (Figoni, 2011). There also exists other element that affect the malleability hence deformation and viscosity of dough content that eventually determines the gas retention level. This is scientifically termed as Rheology of gas retention with regards to baking. The factors which dictate flexibility of the dough are; protein composition and quality in the dough, additional improvers used during dough preparation, the quality of kneading which determines the texture and density distribution in dough and salt concentration (Figoni, 2011).
This practical will be split into two segments with the first highlighting the effect of baking time, yeast, sugar, temperature and salt. The second segment will focus on protein, kneading and additives. A separation of evaluated factors with the findings and analysis will comprise this report ending with a final conclusion about all the factors.
Aim of this Practical
Methods
The methods used in all the practical sessions are referred from the grain technology practical notes.
Discussion1
We can deduce from the above results that low yeast concentration (5 ml) cannot produce a high proportion of gas. However when we increased the yeast concentration (10 ml) the rate of gas production increased too. From figure 1 it is true to say that the rate of gas produced in 15 ml of yeast concentration was at the same level. In this stage there were some errors in the result because the gas production rate is supposed to increase with the time, but this was not the case. This variance in expected results can be attributed to materials and methods mistakes during this practical session.
Discussion2
Yeast is dormant at 0oC – 1oC and begins to be quite active from about 10oC. As dough temperature rises above it, the rate of yeast fermentation increase. The amounts of gas produce in different quantities of yeast are in the range of 0 – 4.5 mm. on the other hand, this is the optimum temperature of different kinds of microorganisms including the yeast.
Discussion3
Salt slows down or blocks yeast fermentation. While the typical amount of salt in yeast dough is 1.8-2.5 percent, bakers can vary the amount of salt basing on their baking preferences while making up the different in final mix for dough preparation.
Discussion4
Small sugar quantities increase the activity of the yeast while large quantities slow down the fermentation process. Large sugar quantities are not added to the dough because yeast can ferment without inhibition or catalysts. Moreover, the amount of sugar has an impact on the final texture and color of the bread.
Discussion5
Texture and Color of bread is directly affected by the time duration taken in the baking process. In the table 5, it is clear that the height of the breads did not make substantial difference between the three types of bread. However, the difference was in the texture and the color of the breads. After 5 minutes of baking the texture was very soft and it got harder when the time was adjusted to 15 minutes and became even harder at 20 minutes. The color equally progressed from white at 5 minutes to deeper brown through 10 and 15 minutes.
Discussion6
Less amount of protein inside the biscuit flour affected the height of dough during different times of the experiment and was characterized by unstable movement. As it is reachable from table number 6, at initial time the height of dough inside the can is around 4.1-4.2 cm for both the flours. However, this height is increasing for baker’s flour due to good structure of protein.
Discussion7
The additives which were used during the experiment were; l.ascorbic acid and sodium metabisulphite. In applying l.ascorbic acid the height of dough increased when the time was to move forward because the volume and rigidity of dough increases by adding this additive. On the other hand, applying sodium metabisulphite ensured the height of dough increased but not as with use of l.ascorbic acid because the sodium metabisulphite is used to decrease the volume of dough as its extensibility increase.
Discussion8
Kneading can be effective by shortening the time used in baking. It is clear from the result above the height of the breads increases when the time of kneading increases as well. Also, the color and texture was improving when the time of kneading increased.
Conclusion
There are many different leavening agents available to the baker. These include active dry yeast, baking powder, salt, sugar and other additives such L.ascorbic acid and sodium metabisulphite. Depending on the baker’s preference in quality and time constraint available, one is able to choose the most appropriate process and ingredient composition while being able to understand the expected outcome.
Table1:
1. Fewer crumbs, texture soft and nice, no crust and light in color.
2. More crumbly, texture soft but crust color was good and was acceptable.
3. Dark color crust and tough texture.
Table2:
1. Well rose, very soft, sunken if pressed, no rigid texture.
2. Slightly rose. Texture a bit firm.
3. Well rose. More loose crumb. A bit soft.
Table3:
1. Cells thicker, firmer, dense structure.
2. More crumbly and more volume.
3. More volume and more open structure.
References
Figoni, P. (2011). How baking works: exploring the fundamentals of baking science. Hoboken, N.J.: John Wiley & Sons
