Activity 4 Worksheet 3 - Lecture notes 1 PDF

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CHEM&110 Chemical Concepts Activity 4: Gels and Foams Name: Christelle Mata Date: 10/19/2020

1.What have you chosen to do, a gel or a foam? Explain what you made, why you chose it, and where to find the recipe. Include a picture of your product! (2pt) I chose a foam; I just google the recipe and find a YouTube video and it didn’t turn out great. It tastes really bad. I chose it because I always wanted to make whipped cream.

2. a) Based on what you chose, describe what makes it a gel (or a foam) - is it protein, fat or carbohydrate based? (1pt) Whipped cream is an air-in-water foam in which air cells are surrounded by a film containing fat droplets stabilized by a film of protein. Partial denaturation of this protein occurs as the cream is whipped. ... Air bubbles incorporated during whipping are trapped in the viscous liquid to form a foam. https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/whipped-cream b) Based on what you chose, describe what is trapped inside those chains (from part a). Is it liquid or is it a gas? Be as specific as possible with what liquid or gas it is. (1pt) I think whipped cream is both liquid and gas and also solid , it has all three phases mixed in there. 3. a) Gels rely on cross-linking. What does that term mean? (1pt) The formation of covalent bonds which hold portions of several polymer chains together is called cross-linking https://chem.libretexts.org/Bookshelves/General_Chemistry/Book%3A_ChemPRIME_(Moore_e t_al.)/08%3A_Properties_of_Organic_Compounds/8.26%3A_Cross-Linking b) Foams rely on protein denaturation. What does that term mean? (1pt) Denaturation is a process in which proteins lose their shape and, therefore, their function because of changes in pH or temperature. https://bio.libretexts.org/Bookshelves/Microbiology/Book%3A_Microbiology_(Boundless)/7%3 A_Microbial_Genetics/7.07%3A_Protein_Modification%2C_Folding%2C_Secretion%2C_and_Deg radation/7.7B%3A_Denaturation_and_Protein_Folding

4. Please answer both of these questions. You may explain them as if you are explaining the science of gels and foams to non-scientists (friends, family, etc.) Use the readings and module from this week to help. Feel free to use the internet too. Cite all sources used. a) In a few sentences, explain what is happening with molecules when gelation takes place. (2pt) When gelation occurs, a dilute or more viscous polymer solution is converted into a system of infinite viscosity, i.e. a gel. A gel may be considered as a highly elastic, rubber-like solid. A gelled solution does not demonstrate any flow when a tube containing the solution is tilted. https://www.sciencedirect.com/topics/chemicalengineering/gelation#:~:text=When%20gelation%20occurs%2C%20a%20dilute,containing%20th e%20solution%20is%20tilted. b) In a few sentences, explain what is happening with molecules when a foam is formed. (2pt) The whisking process stretches out and unravels the proteins and they end up lining up because the hydrophilic ends are attracted to water in the egg white and the hydrophobic ends are repelled and attracted to the air in the pockets. Eventually the protein coating of the air pockets links together, making a foam. https://www.ifst.org/lovefoodlovescience/resources/protein-foamformation#:~:text=The%20whisking%20process%20stretches%20out,link%20together%2C%20m aking%20a%20foam....