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Nicole Rucker

Nicole Rucker is a pastry chef for the Gjelina group, more specifically, Gjelina Take Away in Venice. At the beginning of her culinary career, Rucker worked in various bakeries and cafes across California, from San Francisco to San Diego. In the quest to create the perfect pie crust, Rucker came up with a recipe that helped her win the KCRW Annual Good Food Pie Contest in Los Angeles, as well as a blue ribbon in the National Pie Championship in Orlando. Fascinatingly, her award-winning apple pie utilizes dried apples and cardamom.

Pastry Chef Nicole Rucker of Gjelina Take Away- Los Angeles, CA

What hooked you on cooking?
In short – Failure. I used to watch a lot of cooking shows as a teenager, and I would try to make the recipes from the shows for my family. I grew up in a single parent household and I made a lot of the meals for myself and my siblings. I wanted to impress a young man one summer and I tried to make a cake from scratch with my best friend, it was a complete mess. So I started from that culinary failure (and the many more to come…) and worked my way to a place of understanding. This is what hooked me, the desire to understand.
The coolest example of science in your food?
The point of doneness and its many indicators. The reactions of methods and applications and ingredients. The scientific method of figuring things out – even down to what tastes good with what. Adding salt to fruit – thats a practical application of a very simple scientific reaction.
The food you find most fascinating?
Fruit and vegetables – Its magical the way nature and man cooperate (or not) to make these things edible. I’ve always been in love with apples and tomatoes and their many varieties.
What scientific concept–food related or otherwise–do you find most fascinating?
The cultivation of produce – I’m not talking about the Monsanto GMO stuff, but the kind of thing my grandpa used to do, tying one citrus plant to another citrus plant, or developing a hotter chile by grafting… this stuff I could hear about all day long.
Your best example of a food that is better because of science?
Not exactly a food but a process – fermentation. My life would be less without cheese/wine/miso/bread…
How do you think science will impact your world of food in the next 5 years?
The more people become interested in their food and food systems, the more people want to understand the world of food. This could lead us to a greater appreciation for quality, sustainability and the science of food. Not the science of creating artificial foods and flavors but the science of keeping a sustainable food system alive that can extend the availability and the appreciation of quality, healthful, interesting food to everyone. Rich or poor. Idealistic but hey…
One kitchen tool you could not live without?
My hands.
Five things most likely to be found in your fridge?
Mustard, Aged White Cheddar, kale, eggs, BUTTER.
Your all-time favorite ingredient?
Well, salt is the always favorite ingredient… but other ingredients come and go, my favorites change by the week or the season. Currently in heavy use is buckwheat flour. Talk to me in a few weeks and it will probably be lemon verbena and further into summer… elephant heart plums.
Your standard breakfast?
Eggs and bacon in any form with toast, coffee or tea.

5 Things About Baking

At our 2013 Science of Pie event, Christina Tosi, Zoe Nathan, and the fantastic students from the Science & Food undergraduate course taught us all about pies, baking, creativity, and the scientific process. We just can’t get enough pie science, so here are 5 fun facts related to baking and some of our favorite baking ingredients:

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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.

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The Science of Cookies

How would you describe your perfect chocolate chip cookie? Thin and chewy? Ultra-crispy? Thick and cakey? Whatever your preference, knowing how to manipulate the ingredients in a basic cookie recipe is the first step toward chocolate chip cookie bliss. At last week’s “Science of Cookies” student event, graduate student Kendra Nyberg showed us how to achieve two very different cookie textures by riffing off of the classic Toll House chocolate chip cookie recipe.

ScienceofCookies

Cookies wait to be tasted (left) while Kendra explains how gluten makes cookies chewy (right)

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Thin, chewy cookies (left) and thick, soft cookies (right)

Thin, Chewy Cookies from Smitten Kitchen
These cookies are all about moisture. A wetter cookie dough spreads more during baking, creating a much thinner cookie. Extra moisture also promotes gluten development in the cookie dough, creating a slightly denser, chewier cookie. This recipe from Smitten Kitchen maximizes moisture content by using melted butter, less flour, less egg white (which can dry out cookies), and a higher brown-to-white sugar ratio (brown sugar can help retain moisture) than the classic Toll House Recipe.

ThinChewyCookieRecipe

Thick, Soft Cookies from My Baking Addiction
Where the previous cookies craved moisture, this recipe from My Baking Addiction removes extra moisture to create thicker, less chewy cookies. Increasing the flour content and using extra cold butter creates a drier dough that spreads less easily in the oven; adding baking powder to the dough lends extra fluffing power. The reduced moisture in this dough also limits gluten formation for a slightly softer (less chewy) cookie.

ThickSoftCookieRecipe

Of course, this is barely the tip of the cookie engineering iceberg. There are so many ways to tweak a cookie recipe to achieve different textures. In addition to this brief introduction, the internet is full of great resources for cookie hacking. This particularly handy guide from Handle the Heat clearly show some of the ingredient manipulations described above. If you end up experimenting with your favorite cookie recipes, be sure to tell us about it in the comments below!


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


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.

Homemade Butter

ButterBigger

Despite the misconception among certain pop culture icons that butter is a carb, butter, like other fats and oils, is a lipid. Broadly defined, lipids are any molecules that have hydrophobic, or water repelling, characteristics.  In contrast to simple molecules like water (H20) or sugar (C6H12O6), butter does not have one molecular formula; rather, it is a mixture of triglycerides. Here is what a triglyceride looks like [1]:

triglyceride

Triglycerides are molecules made of three fatty acids bound to glycerol, a sugar alcohol. Fatty acids are long hydrophobic chains of hydrogen and carbons that repel water. Triglycerides do not have to be the same three fatty acids, but can be mixed and matched. For example in butter, oleic acid (32%), myristic acid (20%), palmitic acid (15%) and searic acid (15%) make up the greatest percentage of the fatty acids [2].

buttercontent

In addition to all these lipids, surprisingly, butter contains water. While oil and water don’t normally mix, in butter, tiny microscopic water droplets are dispersed within the fat.  This is commonly known as a water-in-oil emulsion. An emulsion is any mixture of two liquids that don’t usually mix. The opposite of a water-in-oil emulsion would be an oil-in-water emulsion in which oil droplets are entrapped within water.

To understand the secret of how butter can be made of two immiscible liquids, we need to delve back into the molecular structure.  Butter is made from the cream, which has a higher fat content (15-25%) than milk (5 – 10%) [3].  In milk and cream, which are oil-in-water emulsions, the fatty triglycerides stay suspended in liquid because they are encapsulated in tiny fatty spheres or globules. Each globule is surrounded by a nanoscopically thin layer of phospolipids and stabilizing proteins. Phospholipds have hydrophobic lipid tails that love to repel water; they also have hydrophilic, or water loving, heads that contain a phosphate group (thus the name, phospho-lipid). Here is a picture of a phospholipid [1]:

phospholipid

The phospholipids organize themselves in a thin layer so that the water repelling hydrophobic portions are aligned with the fatty acid chains while the water loving hydrophilic heads interact with the milk liquid.  This allows the fats to remain dissolved in the milk and float around like little water balloons.

Milk Fat globule. (A) Diagram of the phosopholipid layer surrounding a fat globule [3]. (B) Cryo-electron microscopy image of a fat globule [4]. The scale bars are 0.1 μm.

Now, that we have talked about the structure of butter, how to get from cream to butter?  (Remember: milk and cream are oil-in-water emulsions and butter is a water-in-oil emulsion.) The oil-in-water emulsion of the cream is reversed into a water-in-oil emulsion in butter. During the churning or mixing process of butter making, the fatty globules in the cream break open to release the entrapped fat molecules. The hydrophobic fat molecules clump together and mix to form larger fat globules that coalesce into larger solid fat droplets. This processes pushes out the liquid portion and the solid portion becomes the butter.  Since these types of fat molecules typically melt at temperatures of 30 to 41°C (86 to 106°F), this means that at cool temperatures below approximately 39°F (4°C), the remaining liquid gets trapped within the solid fat matrix and is unable to separate out of the butter [5].

milktobutter

Below is a recipe for making your own homemade butter. You don’t need fancy equipment or churners like your ancestors used; a well-sealed glass jar works wonders.  The shear forces generated by rigorous shaking are sufficient to convert your cream into butter.

Ingredients

Heavy whipping cream (6 cups makes about 1lb of butter)
Salt, to taste
Jar with lid, any size

Procedure

1. Fill the jar about ¾ of the way to the top with the heavy whipping cream and close the lid.

2. Shake the jar for about 4-5 minutes until the cream begins to thicken. Shake longer if you wish for a thicker consistency.

The shaking motion breaks down the fat globules. The membranes surrounding each fat globule break, releasing the hydrophobic triglycerides. The triglycerides clump together and push away the hydrophilic liquid, the buttermilk.

3. Drain off the buttermilk and place butter in a small bowl. Knead the butter under cold running water to remove any remaining buttermilk.

4. Salt to taste. Form butter into a ball or log. Serve immediately or refrigerate.

Recipe Adapted From:

Online Resources

  1. General Chemistry Online: What is the chemical structure of butter?
  2. “Overview of the Buttermaking Process” from University of Guelph

References Cited

  1. K562. Overweight & obesity. http://www.indiana.edu/~k562/ob.html
  2. Fatty acids in butter. Percentage composition from Practical Physiological Chemistry, P. B. Hawk, O. Bergeim, Blakiston:Philadelphia, 1943.
  3. Gallier, S. et al. 2012. Structural changes of bovine milk fat globules during in vitro digestion. J Dairy Sci. 95(7): 3579- 3592.
  4. Robenek, H. et al 2006. Butyrophilin controls milk fat globule secretion. PNAS. 103 (27): 10385-10390.
  5. Butter: Some Technology and Chemistry. http://drinc.ucdavis.edu/dfoods1_new.htm

Vince ReyesAbout the author: Vince C Reyes earned his Ph.D. in Civil Engineering at UCLA. Vince loves to explore the deliciousness of all things edible.

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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