Fungi and Food(2)


Apr. 28, 2009

The Picture of Validation Experiment

Solute : sugar and barm
Beaker with clear limewater
Phenomenon after reaction in picture
Apr. 21, 2009

Experiment Process Clip

We are do the experiment to inprove which kinds of the gas what the sugar and yeast react.

File Type: video/x-ms-wmv: 1.39 M

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Apr. 28, 2009

Explanation

According to the reaction,the experimental phenomena was explained reasonably.


  • Conclusion : The gas released by barm and sugar is CO2.
    Apr. 29, 2009

     

  • When we added sugar and barm into clear limewater by stirring , it changed into turbid. According to the knowledge of last semester biology that CO2 is able to make limewater turbid , it is proven that CO2 is the gas released by barm and sugar.
    Apr. 28, 2009

     

  • I have learned that CO2 can change clear limewater into turbid in my first term of seventh grade. Accordingly, teacher takes us into the lab and asks us to prove it by ourselves with following steps.
    1.Stir barm and sugar in the hot water of lab container.
    2.Insert a plastic pipe into the beaker with clear limewater.
    After a while, there is little air bubble from it . Within 20 mins, it changes from clear to turbid with more foam rising by sugar and barm.
    Apr. 28, 2009

     

Apr. 29, 2009

About ferment

Why is bread and steamed bun are floppy and spongy?


  • When yeast is heated, CO2,which can let the bread more soft will been created.
    Apr. 29, 2009

     

  • When yeast is added into dough, it get nutrient from the monosaccharide decomposed by amylase. At the moment, yeast secrets enzyme which can decompose monosaccharide into Ethanol，carbon dioxide and heat. The gas is surrounded by gluten and format stomata, so the dough expanses and becomes soft.
    Apr. 29, 2009

     

  • In the experiment process we find the gas can make whitewash be turbid, so we can determine the gas is CO2. When yeast is used to make bread, the gas will be created and lead pores to appear. This Phenomenon makes the bread soft.
    Apr. 29, 2009

     

  • The main raw material for bread is flour. The baker adds certain amount yeast into the dough, after kneading redients the flour to dough. Yeast is a type of beneficial fungi, and under certain conditions, yeast breeds rapidly and abundantly. When being kneaded into wet dough, the yeast starts breed. The yeast secretes a variety of enzymes, which can decompose starch into dextrin. And then further the dextrin is decomposed into maltose, glucose, etc. Finally a large amount of carbon dioxide gas is created. Carbon dioxide in the gluten network of dough let the gluten into a porous subject, the bread becomes soft and porous after being kneaded and grilled is just because the expansion of carbon dioxide in the dough.
    Apr. 29, 2009