Activity

Is it all ham or is there something else?

Characters:

Gerty Theresa Radnitz Cori

Theme: Food and Nutrition

Competencies

Competence in Linguistic Communication

Mathematical competence in science, technology and engineering

Personal, social and learning to learn competence

Citizen Competition

Subjects and year by Educational System

Spain > Biology and geology > 1st ESO > The human body

Spain > Biology and geology > 3rd ESO > The human body

Enunciation

<img title="Women's Legacy logo" src="//inclusion.womenslegacyproject.eu/images/LogoWL.svg" /><hr />1. Introduction&nbsp; &nbsp; &nbsp;Starch is a polysaccharide, a source of energy. It was Marie-Anne Pierette Paulze, wife of Lavoisier (17th century), who was the first person, together with her husband, to conclude that food is a source of energy. Later, in the 20th century, Gerty Theresa Radnitz Cori was the first scientist to study, also with her husband, carbohydrate metabolism at the molecular level. Her studies led to an understanding of how cells consume and store energy from carbohydrates. Thanks to their contributions, they were able to significantly improve treatments for diabetes.&nbsp; &nbsp;You have already studied foods that are rich in polysaccharides such as starch, but... Do we find starch only in these foods?&nbsp; &nbsp;In this practice we are going to verify that, surprisingly, we can find starch in foods that are not very suspicious of containing it, as is the case of ham, and any other type of pork cold meat, turkey, etc.&nbsp; &nbsp; Before starting the practice, you should know that most of the manufacturers of this type of cold cuts add starch to the meat during the elaboration process. This allows them to obtain a greater quantity of cold meat from the same initial quantity of meat. The cost of production, for example, of York ham, is considerably reduced with the addition of starch to the final product. This represents a fraud for the consumer since, when buying cold cuts of pork, turkey, etc., he pays "at the price of meat" for the added starch.&nbsp;
2. Materials&nbsp; &nbsp; &nbsp;For the realization of this practice we are going to use:&nbsp; &nbsp; &nbsp; -Pork cold cuts, turkey, chope, ...&nbsp; &nbsp; &nbsp;-Plastic plates.&nbsp; &nbsp; -Iodine-lugol solution.&nbsp; &nbsp; -Bleach.&nbsp;
3. Procedure&nbsp; &nbsp; &nbsp;What you are going to do is to qualitatively assess the starch added to the cold cuts. You will do this by using the property of starch to stain violet with iodine solutions. Therefore, if the cold cuts you want to analyze have a lot of starch added to them, when you add a few drops of iodine, they will be stained an intense violet color. On the contrary, if the cold cuts do not contain starch, they will not give any type of coloration.&nbsp; &nbsp; &nbsp; Before adding the lugol, you must remove the colorant that is added to the cold cuts to obtain a pink color. Manufacturers add this colorant to make their products look more appetizing. To remove this coloring we will use bleach, so the procedure to follow would be the following one:&nbsp;
1. Write down in the table below the brand, type of product and price per kilo.&nbsp; 2. Take each of the pieces of cold cuts and leave them for two or three hours submerged in bleach (to eliminate the dye we have talked about). If you have little time to carry out the activity, you can skip this step. It is not essential to see the final result.&nbsp; 3. After this time, wash each piece of ham well under the tap. Be careful not to splash bleach on them, you could ruin all your clothes!&nbsp; 4. After having washed thoroughly to remove all traces of bleach, add a few drops of lugol to each piece of ham.&nbsp; 5. Observe the color of each piece.&nbsp;
3. Results &nbsp; At the end of the practice, answer the following questions:&nbsp; &nbsp; &nbsp;a. Which of the pieces of cold meat is stained more intensely?&nbsp; &nbsp; &nbsp;b. What does this mean?&nbsp; &nbsp; &nbsp;c. Do you find any relationship between the intensity of coloration and the price of the cold meat?&nbsp; &nbsp; &nbsp;d. Write your conclusions after performing this practice.&nbsp; &nbsp; &nbsp;e. Look up information about Gerty Therea and Marie-Anne Pierette. Do you find any parallels in their lives with respect to the problems they had in doing their work, the way they solved them, their publications, etc.? Write your conclusions.
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<td style="width: 24.975891996142717%; text-align: center; height: 22px;">Brand</td>
<td style="width: 24.975891996142717%; text-align: center; height: 22px;">Type of cold meat</td>
<td style="width: 24.975891996142717%; text-align: center; height: 22px;">Price/kilo</td>
<td style="width: 24.975891996142717%; text-align: center; height: 22px;">Staining (none, little, much)</td>
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Observations and context

Gerty had many difficulties to develop her research work because she was a woman, and as happened to her predecessor Marie-Anne Pierette Paulze (1758-1836), wife of Lavoisier, now considered the mother of modern chemistry and nutrition, working as a team with her husband opened the doors to work in a laboratory. During the 20th century, many women dedicated themselves to scientific research, such as Rachel Carson (1907-1964), a marine biologist, zoologist and writer, who concluded after several studies that pesticides were devastating the environment. Tu Youyou Chinese scientist, known for discovering artemisinin (also known as dihydroartemisinin), used to treat malaria who in 2015 won the Nobel Prize in physiology and medicine. Theo Colborn who researched toxic chemicals extending Rachel Carson's legacy. Lise Meitner, the only woman to have an element of the periodic table named in her honor: meitnerium. Frances Oldham Kelsey, contemporary and connoisseur of the author's work, devoted herself to pharmacological medicine and prevented the use of thalidomide in the USA, which prevented the tragedy that occurred in other countries.

Description

Learning situation. This is a laboratory activity on the use of starch in the production of cold cuts.
Objectives:
-Check that the cold cuts we buy are sometimes composed of substances we do not expect.
-To reflect on the importance of selecting well the food we eat and on the strategies of the food industry to stimulate consumption and make food more attractive.
-To learn about the usefulness of reagents, such as lugol, to quickly and easily detect the presence of certain substances. In this case, starch in food.
Specific competences: CE1, CE2, CE3, CE5
Timing: one session. The report can be done by the students at home.
Spaces/resources: Biology laboratory, material described in the practice script and cold cuts (it is recommended that students bring the cold cuts they use at home, with the brand and price of the same). Evaluation criteria:
-To execute the practice correctly using the laboratory material in an appropriate way.
-To be able to argue conclusions in a critical way according to the results obtained, using an appropriate language.
Curricular Evaluation of the students: The students will be evaluated attending, on the one hand, to the self-evaluation rubric and on the other hand, to the contribution of material (stiffs), the adequate execution of the practice, the annotation of results and the corresponding conclusions.

Observations: To do this practice it is convenient to ask the students to bring some cold cuts of turkey, ham, mortadella, etc., from home, noting the brand and the price per kilo. In this way, they can analyze the quality of the products consumed in their own homes.

Is it all ham or is there something else?

Enunciation

Observations and context

Description

Answer

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