BAKED PRODUCTS 

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:

Unleavened

• made without any leavening (gas producing) agent. Non-leavened baked
  goods do not rise and make shrink during baking. Examples are pie crusts,
  strudel and tortillas

Leavened by water vapor:

• expansion of water vapor in important in all leavened products, but some
  products are leaved by water vapor alone. Products include puff pastry,
  crispbreads, eclair shells, cream puffs and popovers.

Leavened by air:

• products no chemical leavening agents or yeast are added and where air cells
  are produced during mixing the mixer bowl. These products include Angel
  food cakes, pound cakes, sponge cakes and cheesecakes

Chemically leavened:

• the production of air cells by the production of gas during mixing and baking
  is utilized for the manufacture of a large number of different baked goods. Chemical leaving is achieved by the action of. Product of this type include soda breads, scones, muffins, pancakes, snack crackers, layer cakes, cupcakes, doughnuts and cookies.

Yeast leavened:

• The growth of yeast in doughs produces carbon dioxide, which in the
  leavening agent in must breads and rolls. Other yeast leavened products
  include variety breads (wholewheat, rye,sourdough, salt rising bread, danish
  pastry, donoughts and cookies

FLOUR:

Flour is prepared by a combination of grinding and classification according to particle size

wheat

"break"

sifting and separation

shorts "Middllings" Break flour

Sifting

Straight Flour

Sifting

second clear patent flour

Sifting

First Clear

    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
        and cookies.

    5. Durum wheat - a high protein, had wheat used primarily for seminalina (a course milled
        flour) for pasta products, including spaghetti, noodles and macaroni.

Ingredients:

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:

• flour
• vital gluten
• sugar/carbohydrates
• oxidants
• reductants
• enzymes
• surfactants (emulsifiers as softeners)
• salt
• calcium
• yeast
• chemical leavening agents(combinations of carbonates and acidify agents - such as
  phosphate salts)
• eggs (serve as heat set protein in place of wheat gluten in cakes)
• water

Ingredients and their roll in yeast leavened bread, rolls and buns include:

    Flours selected for different applications include:

• white bread -chlorinated hard wheat straight flour
• rolls and buns - non chlorinated patent flour
• cakes and cookies - short, patent, chlorinated soft whet flour
• pastry - generally a blend of 80% hard wheat and 20% soft wheat flour

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

Sugar provides substrate for yeast, increases starch gelatinization temperature,
increases gluten denaturation temperature and increases tenderness

Oxidants can be placed in three classes:

• maturing agents -ADA (azido-carbamide)
• bleaching agents - chlorine
• dough improver - bromate, iodate, ascorbic acid and ADA

Oxidants serve three functions:

• oxidation of flour lipids
• oxidation of carotene
• oxidation of sulphydryl (-SH) groups and pentosans (added at dough stage)

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:

• mixing
• make-up
• proofing
• conveying
• first stage of baking

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
bond compounds.

Surfactants are used in breads to increase shelf-life and in cakes to improve
tenderness. Common sufactants (often used in combinations) include:

• mono and di-glycerides
• sodium steroyl lactylate (SSL)
• Diacetyll-tartrate esters of fatty acids (DATEM)
• Polyoxyethylene mono-glycerides (EMG)
• succinyl mono-glycericdes

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:

• amylases to provide substrate for yeast fermentation and reduce starch
  retrogradation during baking of bread
• pentosanases decrease dough viscosity and increase loaf volume in bread
• lipoxygenases increase mixing tolerance
• proteinases partially degrade proteins and decrease mixing time and improve
  the flow characteristics of roll and bun doughs.

Salt enhances 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%

Calcium complexes 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:

• hydrophobic bond interactions
• hydrogen bonding
• electrostatic reaction (ionic interactions)

Important interactions include:

• protein/protein
• protein/starch
• lipid/starch
• lipid/protein
• salt/protein
• salt/starch

Bread Making Processes:

Bread, rolls and buns are made with a variety of process. Listed in order of decreasing time of fermentation, these are

• sponge dough
• straight dough
• liquid ferment
• mechanical dough development (Chorleywood process used in Europe, but not
  common in the USA

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.

Bread Faults:

Common problems found in breads and their most common causes are shown in the following tables:

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