Tag Archives: protein

A good egg!

                                         
What eggs say....by JWU student Rebecca Ramey

What eggs say….by JWU student Rebecca Ramey

For bakers, these are the four major food groups: flour, sugar, fat and eggs.  The  previous baking science blog posts have already given fun facts about flour, sugar and fat, so now it’s time for eggs!

Egg shell color, does it really matter?  Marketing today tells us that brown eggs are healthier than white eggs, and therefore the consumer is charged more.  Is that really necessary?  No.  White or brown, the contents are the same, and the nutrition value is the same.  The color of the shell depends on the breed of the chicken.

Brown eggs vs. white eggs

Brown eggs vs. white eggs

Egg parts:  Shell, membranes, air cell, egg white (albumen), egg yolk, chalazae.

Fun facts:                                                                                                                                          1. The older the egg = the larger the air cell.  When hard-boiling eggs, it is much easier to remove the shell from an older egg than from a very fresh egg.                                                      2.  The less prominent the chalazae (the twisted egg white cord that holds the yolk in place), the older the egg.                                                                                                                             3.  Worldwide, around 1.2 trillion eggs are produced for eating every year. The average person on Earth consumes 173 eggs a year. (www.britisheggweek.co.uk)

Parts of an egg

Egg composition:                                                                                                                            76% water                                                                                                                                     12% protein                                                                                                                                  10% fat                                                                                                                                             2% sugar

Functions of eggs:  structure, aeration, emulsification, flavor, color, nutritional value.                     Structure:  adding more eggs to a product will give it a firmer texture.  Example:  fudge-style brownies have relatively low egg content.  Cake-style brownies have a higher portion of eggs in the recipe.

Aeration:  whipping egg yolks or whites within the MOP of a recipe will incorporate more air into your product.  Some products are leavened solely with the whipping of eggs (example: chiffon cakes).

Emulsification:  the lecithin in egg yolks allows fat molecules and water molecules to combine more readily.

Flavor:  eggs enrich the flavor of products, giving them a more complete flavor profile.

Color:  egg yolks give an eye-appealing rich color to baked goods.  Also, the additional protein in eggs aid in the browning of the crust of breads, rolls or cookies.

Nutritional value:  eggs are jam-packed with protein, minerals and nutrients for their relatively small size.

How do we use eggs?  fried eggs, omelets, quiche, custards, meringues, soufflés, cakes, breads, cookies, muffins…..they are everywhere!

IMG_0773Fried eggs:  note the difference in the size of the yolks.  These were all graded as “large.”

IMG_0597

Over-whipped meringue:  feels like styrofoam.

IMG_0596Perfectly whipped soft-peak meringue.

Meringue topped tartlets

Meringue topped tartlets

Egg custard

Egg custard

Check out these sites:                                                                                                                    The American Egg Board  www.aeb.org                                                                                         The Canadian Egg Council  www.eggs.ca

For a more in-depth look at eggs or just about any ingredient, explore the contents of this great book by Harold McGee.

On Food and Cooking, The Science and Lore of the Kitchen, by Harold McGee

On Food and Cooking, The Science and Lore of the Kitchen, by Harold McGee

“Love and eggs are best when fresh.”  Russian proverb

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Baking Science…..how does baking work?

Students in my How Baking Works class, observing a demo.

Students in my How Baking Works class, observing a demo.

So how does baking work? This week we will look at different basic ingredients and how they function within baked products.  For my How Baking Works course, we focus a full day on the particulars of one specific ingredient, conduct experiments and analyze our products.  (Think…..Scientific Method meets The Bakeshop.)

For the first post in this series of baking science, we’ll look at flour and gluten.

Flour: Different types of flours and their protein contents. Why is the protein content of the flour important?  The protein content of each type of flour correlates to the gluten-forming proteins in that flour.  These proteins help give the baked product the desired taste, color, structure and texture necessary for the desired characteristics of that product.  For example, we use cake flour to make cakes light and tender,  and we use bread flour to make breads chewy and satisfying.  In the baking world, we use various flours for different products: cake flour, pastry flour, bread flour, and high gluten flour.

For this experiment we made a basic “lean dough roll,” which consists of flour, salt, yeast, and water.  Our control product (the correct flour for the roll) was the roll made with bread flour.  We also made rolls with cake flour, pastry flour, high gluten flour and a product called Vital Wheat Gluten. This experiment proved the function of flours and the function of protein in flour.

Here are our findings:

  • – the higher the protein content of the flour, the darker the crust of the roll
  • – the higher the protein content of the flour,  the taller the roll will rise
  • – the higher the protein content of the flour, the more open pore structure within the roll (larger air pockets).  More protein means more air (carbon dioxide gas) can be trapped from the yeast fermentation, causing larger air bubbles within the roll.
  • – flour absorbs moisture.  The higher the protein content of the flour, the more liquid it can absorb.
  • -flavor. Flours with a lower protein contain more starch and less flavor.

Lean Dough Rolls

This photo shows our lean dough rolls that were made with the various types of flours, ranging from cake flour (about 6% protein) to vital wheat gluten (about 75% protein). Vital wheat gluten is an additive used to supplement the protein content of products (like whole grain breads) that are made with lower-protein flours such as rye, oat, spelt or buckwheat.

Gluten:  Gluten, a stretchy gummy substance, forms when the gluten-forming proteins in flour (glutenin and gliadin) come in contact with moisture (water) and motion (mixing).  This substance gives our products the stability necessary for proper structure development.  Gluten is a buzz word these days in the world of nutrition.  Gluten-free products are very popular and although a dietary necessity for those who have Celiac disease or a gluten intolerance, they are not healthy for people on unrestricted diets.  Celiac disease is an auto-immune condition where the body (specifically the small intestine) can not properly digest gluten, therefore causing a number of unfortunate side effects.

Check out the National Institute of Health’s website for more information on Celiac disease and gluten sensitivity:  http://www.celiac.nih.gov

Also check out King Arthur Flour’s website for information on flour, recipes, and products:  http://www.kingarthurflour.com

Baking science.  Too much information? Or are you fascinated with this topic?

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My resource for this information, the book How Baking Works, written by food scientist Paula Figoni, serves as the basis of our curriculum for the How Baking Works class, one of the fundamental courses for the IBPI (Baking and Pastry) majors at Johnson & Wales University.