Molecular Gastronomy Lab Lesson Plan: Spherification and Olive Oil Powder For an advanced high school Chemistry class Topic and Purpose: Exploring transformations from one molecular state to another through processes from food science and molecular gastronomy, students will learn how chemical interactions are used to change the textures and perceptions of edible liquids. The lab will illustrate chemical principles in a hands-on experiment that has connections to realworld applications. Spherification and powdering fats are two techniques of molecular gastronomists used to deconstruct and alter foods for a new eating experience. Creating a powder out of liquid is also used in the processed food industry to capture flavors in a dry form. But beyond that, these two processes involve chemical interactions that students learn about and can then see firsthand. Spherification makes use of the interaction between sodium alginate (which is mixed into a flavored liquid) and calcium (which is dissolved into a solution as a bath for spheres) to form a thin gel layer at the surface of drops of a flavored liquid. This results in spheres of liquid that burst when eaten. It allows for a new way to eat and perceive liquids. Making olive oil powder, while not a dehydration of a liquid, is a method of transforming liquid fat into a solid powder. The tapioca maltodextrin molecules absorb, the fat into the spaces between them, not quite bonding with them, but creating a powder nonetheless. Driving Questions: How do chemical interactions drive the transformation from liquid to solid (gel or powder)? How do different polysaccharides interact with other molecules? How can chemical concepts be applied to the food production industry? Does changing the texture and molecular state of foods affect taste and mouth-feel perception? Objectives for Students: Understanding basic concepts of diffusion, gelling, transformation, and stabilization from pre-lab readings about the underlying processes of Spherification and powder creation Understanding the molecules involved in these processes through pre-lab molecular drawing activity Following instructions and understanding how various steps contribute to the overall process via changing variables Practicing detail-oriented qualitative observation and note taking Understanding the broader applications of these processes and their effects in society Materials (for each group): Spherification: 1000 ml of distilled water 5 g Calcium chloride 5 g Sodium Alginate 1000 ml Flavored liquid (not too acidic, alcoholic, nor calcium-containing) Syringe Measuring spoons, spoons & bowls ph paper Sodium citrate Large bowl of distilled water for rinsing spheres
Olive Oil Powder: 80 g olive oil 25 g (0.9 oz) Tapioca Maltodextrin [N-Zorbit M type] o Up to 45 g may be necessary to obtain correct texture 3 g salt Whisk Something to put olive oil powder on: toast, crackers, tomatoes, popcorn Procedure: 1. Brief class discussion of pre-lab readings and molecular drawing activity (with correct diagrams of sodium alginate, calcium, and tapioca maltodextrin drawn on board) 2. Students will be assigned to groups of 3-5 students. In groups, students will follow handed-out lab instructions to prepare then refrigerate solutions for Spherification, make olive oil powder, then return to Spherification to form final product to manage time well 3. Spherification Procedure 1. Test ph of flavored liquid - if the ph is below 3.6, adjust ph so that it is above that measurement. [At acidic ph levels, alginate becomes insoluble as algenic acid, and this inhibits the Spherification processes.] 1. Add small amounts of sodium citrate to the flavored liquid, testing its ph after each addition until the ph rises above 3.6 2. Add 5 g of sodium alginate to 1000 ml of cold flavored liquid. Mix with immersion blender or regular blender. 3. Let solution rest in the fridge for 1 hour to eliminate the air bubbles. 4. Prepare the calcium bath (that will create the spheres) by dissolving the calcium salt in a bowl to obtain a solution with 0.18% calcium. Stir together 5 g of calcium chloride with 1000 ml of distilled water. (Here students will break and do the Olive Oil Procedure) 5. Once the flavored liquid +sodium alginate solution has been in fridge for 1 hour, prep the area and supplies (spoons, syringe, fill a large bowl with distilled water for rinsing) for making spheres. 6. Fill measuring spoon of desired size or syringe with the flavored liquid and carefully pour or drop it in the calcium bath. If using a syringe, create droplets by placing syringe about 3 inches above the bath surface. If using a spoon, wipe the bottom with a paper towel, place the spoon over the bath slightly touching its surface and flip it to pour the liquid into the calcium bath. a. Students can experiment with sphere sizes to see & record how that affects how long they must stay in calcium solution and the final texture and flavor of spheres. 7. Stir the bath gently with the slotted spoon without touching the spheres. If you let them sit in the bottom of the bath, they will flatten and if you let them float, the top won't be covered with the calcium solution and won't gel. 8. If making caviar wait for about a minute and if making large spheres wait for about 2 minutes. a. Students can experiment with the length of time spheres are kept in the calcium solution to see and record how this affects their final texture. (When debriefing, teacher should explain that the longer students wait, the thicker the gel will be because more calcium will
diffuse into sphere. When making spheres for culinary experiences, a good eating experience, results from a gel layer that is as thin as possible but is still strong enough to hold the shape and allow for careful handling. 9. Carefully remove the spheres from the calcium bath using a slotted spoon and rinse in bowl with clean water. Remove and place on plate. 10. Students will try the spheres, observing and noting their taste and texture. a. Students can experiment with letting the spheres sit for varying amounts of time to see how this affects their texture and amount of liquid contained in the gel coating. (They will start to harden in 10-20 minutes.) 4. Olive Oil Procedure: a. Whisk together the olive oil, Maltodextrin and salt in a bowl until it converts to a powder. Additional tapioca maltodextrin may be needed to get it to a powdery consistency. b. Add it to any dish that goes well with olive oil. Make sure it doesn t come in contact with liquid or the powder will start melting. 5. Whole class debrief a. Teacher should lead discussion to get students thinking about the processes that they witnessed. b. Students should share how their groups individual processes turned out and start brainstorming explanations for their results if they varied liquid type/ph. Additional lab steps for further exploration with Spherification: 1. As noted in the lab, students can let the spheres sit for shorter or longer amounts of time to decrease or increase calcium diffusion. This will either result in a thin gel coating because the calcium hasn t had time to diffuse far enough into the drops to gel the outside layer, or a thicker gel coating/entirely gelled sphere because the calcium diffused far into the droplet of flavored liquid. Students can observe how the amount of time in the calcium solution affects the spheres textures and include those observations and potential explanations in their lab write up. 2. To increase the breadth of the experiment, each group can be given a different flavored liquids with different ph levels. Within their groups, students can also make multiple solutions of their flavored liquid that have different adjusted ph levels. Adding different amounts of sodium citrate to change the ph of multiple batches of the flavored liquid will allow them to see how this may affect the liquid and sodium alginate solution, and how that will affect the final texture of the spheres. Thus, when the class comes together to discuss the results, each can describe how their spheres turned out given the ph of their flavored liquids and the adjustments they made with sodium citrate. -This is a good chance to talk about the calcium diffusion process and how that affects the texture and the liquid to gel ratio of the spheres. In addition, teachers can discuss with students the way ph can affect the jellification process, especially when the ph is too acidic (which makes alginate insoluble and thickens the solution). Sample reflection questions for students to answer in lab reports: Spherification: -Why does the hydrocolloid that we used (sodium alginate) require calcium to form a gel? Explain the process that creates the gel layer.
-Why do you think the flavored liquid needed to be cold when blending it with the sodium alginate? -How did the amount of time spheres sat in the calcium solution affect their texture? Why? -Why is testing and adjusting the ph of the flavored liquid necessary? How does this relate to concepts of acidity and solubility that we have covered? -If this happened, how did solutions of different ph levels behave differently when forming (or not forming) spheres in the calcium bath? What are possible exlpanations for this? -How did the solid gel texture of the spheres affect the taste? How does it compare to drinking the liquid in its original state? -Does this improve the eating experience? Do you see it having a future in with consumers and at restaurants? -Does this have any practical applications beyond culinary science and artistry? Olive Oil Powder: -Explain the molecular process that occurred when you mixed the olive oil and tapioca maltodextrin. How does this reflect the transformation and stabilization processes we have discussed in class? -How is the process that occurred different from dissolving? -How did the powder texture of the olive oil affect its taste? How does it compare to olive oil in its liquid form? -How is the polysaccharide maltodextrin (N-Zorbit M) different from the polysaccharide sodium alginate used in Spherification? -Stabilizing high fat ingredients has become a major process for industrialized food production. Where could you see powdered fats being used to create or better a food product? [ie. This process is currently used to turn flavors into powders to coat chips or crackers] -Do you think there are any consequences to making this process more commonplace? Personal Reflection: Processes of molecular gastronomy that use food science to illustrate principles of chemical binding and transformation are an opportunity to make concepts learned in science classes more than just diagrams and explanations. Seeing the processes come to life, especially in instances like this where there are phase changes, is enlightening for students and helps to solidify their understanding of what can be abstract concepts. When putting together the lab procedure, it seemed like a fairly simple process, and all of the videos made it seem straightforward. But as we moved through the steps, it became clear that working with these compounds and solutions was more nuanced than we realized. There are a lot of variables when setting up interactions between chemicals with a desired result, a concept that seems integral to chemistry. With a few variations and unexpected incidences, students are able to see exactly how small changes can make a big difference in the interactions that occur. I took the knowledge I gained from our own experimentation especially in the case of Spherification, which didn t work for us the way we expected it to to make suggestions for varying procedures of this lab and to frame and shape the lab reflection questions. I think it was important that our lab didn t go perfectly it made us think critically about the processes and try to figure out exactly which parts may have caused
the weird textures of the solutions and the misshapen spheres. We learned just how important the juice type and contents are, hypothesizing that the sweet potato juice base of our chosen flavored liquid may have affected the liquid and prevented proper jellification. This could be something students could explore using pure juice from one fruit or vegetable versus using a mixture like V8. For students, unexpected results or a lack of results would be a learning experience, so I made room to allow for that in the lesson plan. Our GISP also decided at the last minute to make three flavored liquid and sodium alginate solutions, each with a different ph, to see if that had an effect. Though it was hard to tell because we didn t get many successful spheres, the solution whose ph was not altered (no added sodium citrate, ph was 5.5) seemed to work the best. From that, I included additional steps in this lesson plan to include this ph varying, because I think it is important to explore, especially if working with a juice that is very acidic and requires adjustment. Group discussion after the lab plays a big role here, especially if different groups use different liquids and/or different ph s and obtain different results. They can compare and discuss those results to grow their understanding. A lab like this helps build students lab technique and attention to detail, which as our group learned, is important for this kind of process. We had to follow instructions properly to ensure that the process worked, and we had to practice the mixing and dropping techniques. These are important skills for students in a high school science lab to be developing. This lab also gets at a practical application of science that may not be widely recognized by many people. Molecular gastronomy is still a fairly new field of experimentation, and as our readings showed, it still doesn t have a set definition or set of principles. There are restaurants and individuals experimenting with food taste and perception, as well as big food processors using food engineering techniques to better process and package products. Spherification and creating powders lose some of their perceived abstractness when students are able to experiment with them right in a lab. Sources: https://www.chefsteps.com/activities/the-science-of-spherification https://books.google.com/books?id=iq3pjy7zs6ec&pg=pa318&lpg=pa318&dq=liquid+ to+powder+with+tapioca+maltodextrin&source=bl&ots=hnjtfpybbh&sig=zco4qzymqd P3ccTuh6- nyzr4du4&hl=en&sa=x&ved=0ahukewi0udbvsbbjahudnd4khuyud7c4chdoaqgj MAE#v=onepage&q=liquid%20to%20powder%20with%20tapioca%20maltodextrin&f=fal se