Ingredients and Food Science Yeast Breads Ingredients and Food Science

Basic Ingredients Yeast bread has 6 basic ingredients Flour Liquid Salt Yeast Fat Sugar OPTIONAL Eggs

Flour Flour give structure/body to bread because of the protein gluten When flour is thoroughly mixed with a liquid and kneaded, gluten is formed and able to support CO2 produced by yeast Gluten becomes more elastic as flour is manipulated or kneaded (Example: gluten is like bubble gum – when you first put it in your mouth, it is soft and chewy, it becomes more elastic as you chew, so you can blow bubbles. If you chew it for too long, it gets tough and hurts your jaw.)

Yeast Yeast is a living organism, a one-celled fungus Feeds on carbohydrates (sugar, flour) and converts them to carbon dioxide (CO2) and alcohol during a process called fermentation Yeast is a leavening agent. Leaven means to make light and porous It works best at room temperature and dies at high temperature and activity slows at low temperatures Yeast is purchased in a dry, granular form, as a compressed cake, or in an instant form Compressed yeast requires refrigeration, but granular yeast keeps well on the shelf. Instant yeast requires no prior handling and may be added directly to the dry ingredients. Some flours are self-rising meaning yeast has already been added and, therefore, no additional leavening agents are necessary.

Liquid Water or milk are typically used as the liquid in yeast breads Purpose is to moisten, dissolve, and combine the other ingredients Milk adds nutrients

Salt Without salt, yeast dough is sticky and hard to handle If left out of the recipe, the baked bread will have small holes on the bottom and outside of the product

Sugar Sugar provides extra food for the yeast, so the dough rises faster If too much sugar is added, however, the yeast works more slowly Sugar helps bread to brown and adds flavor and tenderness to the dough

Fat Fat is a tenderizer It traps air and causes the dough layers to separate

Eggs When beaten, eggs incorporate air They add flavor, color, and strength due to protein content

Food Science Principles Kneading Working the dough to develop gluten Add just enough additional flour to prevent sticking Develop a rhythm to kneading Fold dough in half toward the body, push against the dough with heel of hands and continue until the dough becomes smooth and elastic

Food Science Principles Fermentation The process by which yeast converts sugar into carbon dioxide and alcohol It also refers to the time that yeast dough is left to rise

Food Science Principles Shaping Forming dough into desired shape – loaf, rolls, etc.

Food Science Principles Proofing Final rise of shaped or panned yeast products before baking Proofing should continue until the product is doubled in size Underproofing = poor volume and texture Overproofing = sour flavor, poor volume, and paler color after baking

Food Science Principles Baking/Oven spring As yeast breads bake, a variety of chemical and physical changes turn dough into an edible product Gases form, gases are trapped, starches gelatinize, proteins coagulate, fats melt, water evaporates, sugars caramelize Oven spring Because of the expansion of gases, yeast products experience a sudden rise when first placed in a hot oven. This rise is known as oven spring.