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Apple Pie with Peanut Butter Mousse

The Science of Pie – May 19, 2013
People’s Choice Award
Elan Kramer, Caleb Turner (Team “Insert Team Name Here”)

This student duo thought outside the box with this creative apple and peanut butter pie. To create the ultimate peanut butter experience, the team experimented with the effect of egg white content on the texture and density of the peanut butter mousse.

TeamInsertTeamNameHere

photos courtesy of Patrick Tran

Egg white content affects mousse texture. (A, B) Team “Insert Team Name Here” visualized the air bubbles incorporated into peanut butter mousses prepared with different amounts of egg whites. (C) Using image processing techniques, they calculated the mean (red) and median (blue) air bubble areas as a function of egg white content. Their results show that there is indeed an optimal egg white content for creating an light, airy mousse. (D) An egg white is made up of many proteins suspended in water. Whipping incorporates air bubbles into the egg whites, causing the proteins to unfold as they are exposed to air. Denatured proteins [link to ceviche recipe] form networks at the liquid/air interfaces that stabilize air bubbles within the egg white foam.

The Recipe
Frozen apple pie with peanut butter mousse

1 large store-bought graham cracker crust

For the apple layer:
2 tbsp unsalted butter
3 firm-textured cooking apples*, peeled, cored, and sliced
¼ cup granulated sugar
1 tsp fresh lemon juice
2 tbsp powdered sugar
*Team “Insert Team Name Here” used Pink Lady and Granny Smith apples

For the peanut butter mousse:
1 cup heavy cream
8 ounces cream cheese, softened
1 cup smooth peanut butter
¾ cup granulated sugar
½ cup firmly packed light brown sugar
2 tsp pure vanilla extract
2 large egg whites

For the topping:
1 cup heavy cream
1 tbsp powdered sugar
½ cup finely chopped salted dry-roasted peanuts
2 graham crackers, crushed
1 1/2 tsp cinnamon

To prepare the apple layer, melt the butter in a large sautée pan. Stir in the apples and granulated sugar and cook over medium heat, stirring often, until tender, about 5 minutes. Stir in the lemon juice and powdered sugar and cook, stirring, for 1 minute longer. Remove from the heat and refrigerate.

To make the peanut butter cloud layer, use an electric mixer to whip the heavy cream until it holds semi-firm peaks. Cover and refrigerate.

Using the mixer, beat the cream cheese and peanut butter together until smooth. Gradually beat in the sugars, then the vanilla. The mixture will be lumpy, like cookie dough. Add the whipped cream to the peanut butter mixture, slowly blending them together with the electric mixer until smooth.

Clean and dry the beaters. Using a clean bowl, beat the egg whites until they hold stiff peaks. Fold the whites into the peanut butter mixture with a rubber spatula until evenly blended. Put mixture into the pie crust, cover loosely with aluminum foil and freeze for at least 5 hours.

When you’re ready to serve the pie, take it out of the freezer and top with the refrigerated apples. For the topping, add the powdered sugar and 1/2 teaspoon to the cream and use an immersion blender or mixer to whip. Spread over the top of the pie and sprinkle with peanuts, graham cracker crumbs, and remaining cinnamon.

Recipe adapted from Cookstr: Frozen Apple and Peanut Butter Cloud Pie

Apple Pie with Vodka Crust

The Science of Pie – May 19, 2013
Judge’s Favorite Pie
Qiaoyi Wu, Qinqin Chen, Michelle Cheng (Team Aπ3)

Seeking to perfect pie crust texture, team Aπ3 experimented with different liquids that may impede the formation of gluten protein networks. Gluten gives structure and stability to pie dough, but can also make pie dough dense and tough when over-developed. The team examined the porousness, density, and browning of pie crusts prepared with their three different liquids compared to water and concluded that vodka creates the flakiest pie crust.

TeamApi3

photos courtesy of Patrick Tran

Different liquids affect the density of pie crust. (A) Pie crust prepared with alcohol (beer or vodka) is less dense than pie crust prepared with water. Interestingly, carbonated water also lowers the density of the pie crust compared to water. (B-E) Team Aπ3 did not observe much difference in the browning of pie crusts prepared with water (B), carbonated water (C), beer (D), or vodka (E).

The Recipe
Apple pie with vodka crust

For the crust:
1 1/4 cups all purpose flour
1/2 tbsp sugar
1/2 tsp salt
1/2 cup (1 stick) chilled unsalted butter, cut into 1-inch pieces
2 tbsp (approx.) ice water
2 tbsp (approx.) vodka

For the filling:
1/4 cup sugar
2 tbsp all purpose flour
1/4 tsp cinnamon
1 3/4 pounds apples, peeled, quartered, cored, thinly sliced*
*Team Aπ3 used a half Fuji and half Granny Smith apples.

For the streusel topping:
1/2 cup all purpose flour
1/2 cup firmly packed light brown sugar
1/4 tsp ground cinnamon
5 tbsp (2.5 oz) unsalted butter, chilled

Preheat oven to 375F.

To prepare the crust, mix the dry ingredients. Cut in the cubes of butter until the butter forms approximately pea-sized pieces. Add water and vodka one tablespoon at a time, alternating the liquids. Only add liquid until the dough starts to come together and can be formed into a ball. Chill dough for at least 30 min. Roll out the dough and press into a pie pan to form the bottom crust.

To prepare the filling, mix all filling ingredients. Spread the filling mixture on top of the bottom crust. Try to arrange the filling so that the top of the pie is flat.

To prepare the streusel topping, combine the flour, brown sugar, and cinnamon. Cut the butter into small pieces and incorporate into the dry ingredients until the butter is in very small pieces. Spread the streusel topping over the pie filling.

Bake pie at 375F for 45-50 min.

Recipe adapted from Eat Me, Delicious: Apple Pie with Brown Sugar Streusel Topping

Deconstructed Apple Pie

The Science of Pie – May 19, 2013
Best Tasting Pie
Stephan Phan, Kevin Yang, Amirari Diego (Team Apples to Apples)

Using the technique of spherification, this team applied their knowledge of diffusion and gelation to prepare “reconstituted” apples. They found that optimizing both the calcium chloride concentration and gelation time was key to making a delicious modernist apple pie.

TeamApplestoApples

photos courtesy of Patrick Tran

Calcium promotes the solidification of alginate networks. Alginate is a long, negatively charged molecule called a polysaccharide. Positively charged sodium ions (Na+) dissociate from the alginate when dissolved to create a goopy but liquid solution. Doubly charged calcium ions (Ca2+) can bind two different alginate strands simultaneously, thereby crosslinking and solidifying the solution. Increasing the number of calcium crosslinks by raising the concentration of calcium chloride and/or lengthening the soaking time create a more solid gel.

The Recipe
Deconstructed apple pie with pie crust crumbs and spherified apples

10 g sodium alginate
20 g calcium chloride
1 L 100% organic apple juice*
1 L water**

*Team Apples to Apples recommends using pulp-free organic apple juice. Freshly pressed apple juice tends to have too much pulp, while additives in non-organic apple juice may interfere with the spherification process.

**For the Science of Pie, Team Apples to Apples used 10g of sodium alginate in 1 L of apple juice and 20g of calcium chloride in 1 L of water. This recipe does not require such large volumes, but it is important to maintain these ratios as they affect the gelation time for the apple spheres.

Mix the sodium alginate into the apple juice. We recommend using an immersion blender, but whisking vigorously will also work. Let the solution sit until any foaming subsides; if large amounts of foam formed during mixing, you may also want to skim foam from the surface of the solution. The solution is ready for spherification once it has reached almost an apple sauce viscosity.

Prepare your calcium bath by dissolving the calcium chloride into the water. Mix lightly; the solution is ready once all visible particles have disappeared and the liquid it appears translucent again.

To create each spherified apple, scoop no more than one tablespoon (it becomes increasingly harder with bigger volumes) of apple juice solution using a deep spoon and carefully drop it into the calcium chloride solution. It helps to use a second spoon to scoop the apple solution out of the first spoon. This is mainly technique—you will get the hang of it after a dozen or so attempts!

Let the apple juice solution sit in the calcium chloride solution for approximately 30 seconds. There will not be a noticeable difference if left for an additional 30 seconds, but the apple juice solution will continue to solidify as it sits in the calcium chloride solution and fully solidify after about 10 minutes. Feel free to play around with the timing of this step to achieve the desired spherified apple texture.

To serve, place the spherified apple in an Asian-style soup spoon and garnish with a bed of sugar and graham cracker crust crumbs, a sliver of green apple skin, and a dusting cinnamon.

More information about spherification can be found at Molecular Recipes.

Shortbread Apple Pie

The Science of Pie – May 19, 2013
Best Overall Pie
Alia Welsh (Team Sablé)

This solo effort explored the vast parameter space of pie, studying the effect of fat content and temperature on the texture of the shortbread crust, as well as the effect of pH on the browning of the streusel topping. The final winning pie had shortbread made with room temperature standard American butter.

TeamSable

photos courtesy of Patrick Tran

Effect of different fats on the shortbread crust. The quality of the shortbread crust was evaluated based on its color and texture. Porousness (“porosity”) was quantified by converting crust image pixels to black or white, with black pixels representing holes in the crust. A higher percentage of black pixels corresponds to a higher porosity and thus a crumblier crust. The extent of browning was quantified by calculating the RGB values of each crust image and comparing to a “deep golden brown” color standard (RGB 184-134-11). Standard American butter created the most desirable crust in terms of both browning and porosity.

The Recipe
Apple pie with shortbread crust and streusel topping

For the filling:
3-4 Granny Smith apples, peeled and cored
3-4 Fuji apples, peeled and cored
3/4 cup granulated sugar
2 tbsp flour
1/2 tsp salt
1 tsp cinnamon
1/4 tsp nutmeg
1/4 tsp allspice

For the crust:
1 1/4 cups all purpose flour
1/3 cup granulated sugar
1/2 tsp salt
2 sticks of standard American butter at room temperature
1 egg white, separated

For the streusel:
3/4 cup rolled oats
1/2 cup chopped walnuts, pecans, or almonds
1/4 tsp salt
7 tbsp flour
6 tbsp brown sugar
4 tbsp melted butter
2 tbsp honey

Preheat oven to 375F.

To prepare the filling, cut the apples into approximately ¼ inch slices. Combine with the remaining filling ingredients and sautée over low heat until the water from the apples forms a sauce and thickens slightly. Set aside to cool.

To prepare the crust, whisk together flour, sugar, and salt. Cut in the butter with knives or a pastry blender. Pour the mixture into a pie pan and spread evenly with back of a large spoon or measuring cup. The crust should be about 1/2 inch thick.

Bake crust at 375F for about 15 minutes or until the crust is a light golden brown. Allow the crust to cool for 2-3 minutes, then brush with the egg white.

While crust is baking, prepare the streusel. Combine the dry streusel ingredients. Mix in melted butter and honey to form clumps. Set aside.

To assemble the pie, pour filling into the pre-baked, egg-washed crust and sprinkle streusel on top. Bake for about 35 min at 375F. Streusel should be deep golden brown.

Butter Basics & Carl Sagan’s Apple Pie

CarlSaganPie

The New York Times discusses the proper care and handling of butter in baked goods, and Carl Sagan’s epic baking advice gets turned into an awesome recipe. Tastes like science! Read more

The Science of Pie: 2013 Event Recap

On Sunday we held our third and final 2013 Science and Food public lecture: The Science of Pie. Renowned pastry chef Christina Tosi joined us all the way from New York to explain her process for creating new desserts, and Los Angeles native and super-star baker Zoe Nathan shared her tips for baking the perfect apple pie. Guests indulged in delicious goodies from Zoe Nathan’s Huckleberry Café, Compost Cookies from Momofuku Milk Bar, and espresso brewed by four talented baristas.

IMG_0232

Zoe Nathan and Christina Tosi answer questions from the audience after their lectures.

And, of course, there was pie.

For weeks, students from the UCLA Science and Food course have been studying the apple pie and using scientific inquiry and experimentation to try to create the “ultimate” apple pie experience. Students examined everything from how different apple varieties behave in pie filling to how the size and shape of the pie affects baking. Several students also played with unconventional ingredients, including avocado oil, yogurt, chia seeds, and whiskey.

ScienceOfPieCooking

Students prepare their apple pies the morning of the event.

IMG_3444

Students share their research projects and apple pies with the public.

The students presented their research projects and pies at Sunday’s event. While the public enjoyed sampling the scientific treats, the pies were scrutinized by an esteemed panel of judges made up of chefs (Christina Tosi and Zoe Nathan), food critics (Evan Kleiman and Jonathan Gold), and scientists (UCLA Professors Andrea Kasko and Sally Krasne). After tasting the pies a talking with the students, the public voted for their favorite pie and the judges settled on three additional stand-outs. The lucky winners all took home wonderful prizes from our friends at Breville.

Best Overall Pie
Alia Welsh (Team Sablé)
Apple pie with shortbread crust and streusel topping.
This solo effort explored the vast parameter space of pie, studying the effect of fat content and temperature on the texture of the shortbread crust, as well as the effect of pH on the browning of the streusel topping. The final winning pie had shortbread made with room temperature standard American butter.

Best Tasting Pie
Stephan Phan, Kevin Yang, Amirari Diego (Team Apples to Apples)
Deconstructed apple pie with pie crust crumbs and spherified apples.
Using the technique of spherification, this team applied their knowledge of diffusion and gelation to prepare “reconstituted” apples. They found that optimizing both the calcium chloride concentration and gelation time was key to making a delicious modernist apple pie.

Judge’s Favorite Pie
Qiaoyi Wu, Qinqin Chen, Michelle Cheng (Team Aπ3)
Pie crust made with different liquids, including vodka, beer, and sparkling water.
Seeking to perfect pie crust texture, team Aπ3 experimented with different liquids that may impede the formation of gluten protein networks. Gluten gives structure and stability to pie dough, but can also make pie dough dense and tough when over-developed. The team examined the porousness, density, and browning of pie crusts prepared with three different liquids compared to water and concluded that vodka creates the flakiest pie crust.

People’s Choice Award
Elan Kramer, Caleb Turner (Team “Insert Team Name Here”)
Frozen apple pie with peanut butter mousse.
This student duo thought outside the box with this creative apple and peanut butter pie. To create the ultimate peanut butter experience, the team experimented with the effect of egg white content on the texture and density of the peanut butter mousse.

The Science of Pie was the perfect end to a fantastic lecture series. We are so grateful to our amazing lecturers and all the people and sponsors who made the lectures possible. And although the 2014 lectures might seem impossibly far away, don’t worry—the Science & Food blog is not going anywhere! Keep an eye on out for more exciting food science posts, profiles, recipes, and maybe even a few videos through the rest of the year.


Liz Roth-JohnsonAbout the author: Liz Roth-Johnson is a Ph.D. candidate in Molecular Biology at UCLA. If she’s not in the lab, you can usually find her experimenting in the kitchen.

Read more by Liz Roth-Johnson