A wind range of baked products, made primarily with wheat flour, are produced all over the world. Baked products can be classified into the following types:
Leavened by water vapor:
Leavened by air:
Flour is prepared by a combination of grinding and classification according to particle size
sifting and separation
shorts "Middllings" Break flour
second clear patent flour
The baking properties of flour improve upon aging. The effect of aging are frequently achieved in part by chlorination and in part by the addition of oxidants and reductants at the time of dough preparation.
The major flour used in baked products is milled from wheat. There are a wide variety of wheat flours available, which differ in the type of wheat used and in their baking characteristics. Wheat flours include:
1. Hard red spring
wheat - high in protein and strong in gluten. This wheat is especially
good for making yeast leaved bread and rolls.
2. Hard red winter
wheat - intermediate in protein content and gluten strength. Satisfactory
for making yeast leaved white bread.
3. Soft red winter
wheat - low in protein and weak gluten. Especially desirable for making
cakes, cookies and pastries.
4. Soft white winter
wheat - lowest protein content and weak gluten. Usually used for cakes
5. Durum wheat - a high
protein, had wheat used primarily for seminalina (a course milled
flour) for pasta products, including spaghetti, noodles and macaroni.
Not all the ingredient cited for baked goods are used in the same product. However, the number of different ingredients used in a given baked product is much greater than 20 years ago. This is because, in large measure, to the mechanization of the baking industry - resulting in desired to decrease processing times and increase shelf-life.
Ingredients for baked goods include:
Ingredients and their roll in yeast leavened bread, rolls and buns include:
Flours selected for different applications include:
Vital Wheat Gluten
is extracted from flour and used as an additive to strengthen
gluten activity for breads, rolls and buns. Especially used in bread manufacture
when mixing time or fermentation time is reduced
substrate for yeast, increases starch gelatinization temperature,
increases gluten denaturation temperature and increases tenderness
Oxidants can be placed in three classes:
Oxidants serve three functions:
Dough conditioners are selected on the
speed of reaction, point of addition, mixer
design and operation and the degree of strengthening needed at various stress
point. Stress point in the making of bread include:
The rate of reaction of different types of dough conditioners is illustrated below:
Stress points vary with the method of
dough production and the type of dough
produced. Continuous doughs have greater stress at the mixer, whereas high fiber
dough have greater stress at conveying and baking.
Mix time reducers
are used in bread, roll and bun products to reduce make time. They
include reducing agents (ascorbic acid), proteinase, fat oxidants and activated double
used in breads to increase shelf-life and in cakes to improve
tenderness. Common sufactants (often used in combinations) include:
The sufractants (emulsifiers) interact
with starch to retard staling, interact with gluten
to increase elasticity, increase firmness of grain, increase volume of baked product and
aid in air incorporation in cakes.
Enzymes and their actions include:
flavor and modifies mixing time for bread and rolls. Salt is often added
after dough development to decrease total mixing time in breads by up to 30%
with proteins, decreases denaturation temperature, assists in heat
set structure during baking. Too much causes a coarse cell structure.
Bread, Roll and Bun Making:
Because of the large volume of bread, rolls and buns that are manufactured, the making process for these products will be covered in this chapter. For more information on cookies and cakes, refer to outside reading.
Bread, rolls and buns are a solid foam. During dough making and proofing, carbon dioxide is formed and trapped as gas cells in the dough. Prior to baking the gas cells are surrounded by a matrice of hydrated gluten and insoluble starch particles.Bother gluten and starch is coated with shortening, which prevents the matrix from becoming too solid. During baking the gas cells begin to expand - causing dough expansion. With a rise in temperature the starch granules undergo gelation. With gelatinization, starch absorbs water at the expense of gluten. Gluten strands and sheets are partly denatured and join the swollen starch grains - forming a solid lamellae around the gas cells. The crust prevents further expansion, but protects the interior.
Similar events also occur in the manufacture of other baked goods. The addition of sugar to doughs (such as for rolls, cakes and cookies) increases the temperature for starch gelatinization and protein denaturation. This modifies the type of flour used and ingredients required.
Flour composition and gluten
formation: Gluten is a mixture of glutenins and gliadins, which can vary in
types of rations of individual units. These variations are important in bread making and
explain much of the differences observed between different flours. Factors important to
gluten formation and bread structure include:
a. wheat type an variety
b. polar lipid content of flour
c. degree of change is S-S and SH reactions during manufacture
d. starch gelatinization amount and rate, which changes water absorption and dough structure.
Complexing of glutenin and gliadin during
hydration and mixing results in gluten formation.
This complexing involves breaking some S-S bonds and formation of new ones. Although S-S interchange in important to dough structure, other reactions are also important and involve:
Important interactions include:
Bread Making Processes:
Bread, rolls and buns are made with a variety of process. Listed in order of decreasing time of fermentation, these are
Three common methods for making bread in the USA are diagrammed below:
Generally as fermentation time is decreased, the stress on the dough is increase - making the use of additives more critical to the obtain the desired product.
Common problems found in breads and their most common causes are shown in the following tables:
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