Transcript Wheat Flour milling Grains

Day 4
• Wheat
• Flour milling
• Grains
Words, Phrases, and Concepts
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Endosperm
Germ
Bran
Whole grain
Gluten, glutenin,
gliadin
• Dietary fiber
• Whole wheat flour
and wheat flour
• Hard and soft wheats
• Soaker
• Bleaching and
maturing agents
• Amylase and falling
number
• Malting
• Patent, clear, straight
flours
• Aleurone
• Absorption value
Introduction
Wheat:
– Is a cereal grain.
– Most widely grown grain in world.
• Thousands of varieties available, adapted to
different climates.
– Most popular grain in baking.
• Forms gluten.
• Mild, nutty flavor.
Wheat Kernel
• Also called:
– Wheat grain
– Wheat berry
• Three main parts:
– Endosperm
– Germ
– Bran
Wheat Kernel
Whole wheat flour:
– Is ground from entire
wheat kernel.
– Is a whole grain.
White flour:
– Is ground from white
endosperm.
– Also called “wheat
flour”
Wheat Kernel
• Whether cracked, crushed, rolled, or ground,
whole grains have the same amount of bran,
germ, and endosperm as the original grain.
• Whole grains can reduce risk of certain
diseases.
Wheat Kernel
Endosperm
• Contains mostly starch.
– Starch is tightly packed inside granules.
– Embedded in chunks of protein.
• Two important proteins: glutenin and gliadin.
– Form gluten when flour is mixed with water.
– Gluten network is important in structure of baked
goods.
Wheat Kernel
Wheat germ:
• Is the embryo of the
wheat plant.
• Sprouts, or germinates,
into new plant.
• High in nutrients.
• Can be purchased
toasted.
– Nutty flavor.
– Less likely to oxidize
and turn rancid.
Wheat Kernel
Bran
• Protective outer layer of kernel.
• High in dietary fiber.
– Mostly insoluble fiber.
– Good for health.
• Softens and swells when wet.
• Can be purchased as flakes.
– Adds appealing rustic appearance to baked goods.
– Valuable source of dietary fiber.
Makeup of Flour
White flour:
• Ground endosperm.
• Also called wheat flour.
– Do not confuse wheat flour with whole wheat flour.
• Key components:
– starch
– gluten-forming proteins
Makeup of Flour
White flour (cont.):
• Also contains:
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Enzymes (proteins)
Moisture
Pentosan gums
Lipids
Ash
Carotenoid pigments
Classifying Wheat
• Wheat kernels: classified as hard or soft.
• Additional ways of classifying: color of
kernel, planting time, botanical species.
• Six major classes of wheat in U.S.:
– Hard red winter
– Soft red winter
– Hard red spring
– Hard white
– Soft white
– Durum
Classifying Wheat
Hard kernels are hard to mill.
• Starch granules are damaged during milling.
– Absorb water more easily.
• Flours are coarse and gritty.
– Do not pack well when squeezed in fist.
– Good for dusting bench.
Classifying Wheat
Hard Wheat Flours
Soft Wheat Flours
Bread and high gluten
flour
Form strong gluten
Cake and pastry flour
Gritty to touch
Soft and silky
Do not pack well
Pack when squeezed
Yeast-raised breads
Cakes, cookies
Form weak gluten
Particle Size
From largest to smallest in size:
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Wheat berries
Cracked wheat and rolled wheat flakes
Farina and durum semolina
Flours, coarse and fine
Particle Size
Large grain particles:
– Absorb water slowly.
– Require gentle heating or overnight soaking
• Soaked, softened grains called “soakers”
• Can be good source of enzyme activity
Additives and Treatments
• Vitamins and minerals
– Added to enriched flour
– Iron, thiamin, riboflavin, niacin, folic acid
• Natural aging
– Air (oxygen) is the “additive”
• Bleaching and maturing agents
– Potassium bromate
– Ascorbic acid and other bromate replacers
– Benzoyl peroxide
– Chlorine
Additives and Treatments
Additive
Carotenoids
Gluten
Starch
Use
Air
(oxygen)
Whitens
Strengthens
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All flours
Potassium
bromate
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Strengthens
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High-gluten
flour
Ascorbic
acid
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Strengthens
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High-gluten
and some
bread
flours
Benzoyl
peroxide
Whitens
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All flours
Chlorine
Whitens
Weakens
Increases ability
to absorb water
Cake flour
Additives and Treatments
• Amylase
– Enzyme; breaks down starch into sugars
• Most active on damaged starch granules (from
milling)
• Activity increases during early stages of baking
– Has multiple functions
• Provides food for yeast fermentation
• Increases brown color and flavor from baking
• Softens crumb and slows staling
– Falling number: measure of amylase activity
in flour
Additives and Treatments
• Amylase
– Good sources:
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Sprouted wheat berries
Soakers
Diastatic malt syrup
Rye flour
Untoasted soy flour
Malted flour
Dough conditioners
Additives and Treatments
• Amylase activity decreases when:
– Amount of salt in dough is increased.
– Baking temperature is increased.
– Dough is retarded (refrigerated during
fermentation).
Additives and Treatments
• Malted flour
– Grains of barley are malted, or sprouted,
before drying and pulverizing.
– Used for its enzyme activity.
• Amylase and protease
– Also called dry malt, or simply malt.
– Commonly added:
• By miller to bread and high gluten flour.
• By baker to yeast doughs.
Additives and Treatments
• Dough conditioners
– Also called dough improvers
– Added to yeast doughs
– Multi-functional; most common benefit:
• Strong gluten; for high volume and fine crumb.
– Uses
• Large-scale bread bakeries
• Frozen yeast doughs
• To eliminate bulk fermentation of yeast dough
– Saves time, but flavor is sacrificed
Additives and Treatments
• Vital wheat gluten
– Mostly gluten (up to 75 percent)
– Creamy yellow powder
– Added to yeast-raised doughs
• Improves flour quality
• Increases water absorption
– Starting point: add 2-5 percent of flour weight
Commercial Grades of Flour
Patent flour: from heart of endosperm
• Whitest in color, lowest in ash.
• Most expensive.
• Most white flours are patent flours.
Commercial Grades of Flour
Clear flour: from outer part of endosperm
• Contains aleurone layer
– Nutrient rich
– High in enzyme activity
• Used in rye and multi-grain breads
Commercial Grades of Flour
Straight flour: from entire endosperm
• Not commonly used in U.S.
Milling
• In U.S. flours are milled based on
separation of endosperm from bran and
germ
• For whole wheat flour- recombined
• Distinct difference between milling of
whole grain
Patent Wheat Flours
Bread flour
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From hard red spring or hard red winter wheat
High in gluten-forming proteins
Unbleached or bleached
Often contains malted barley flour
Uses: breads, rolls, croissants, sweet yeast
doughs
Patent Wheat Flours
Artisan bread flour
• From hard red winter wheat
• Compared with regular bread flour:
– Lower in gluten-forming proteins (for irregular crumb)
– Less water absorption (for crisper crusts)
– Usually no added bleaching or maturing agents
• Uses: crusty lean baguettes, flat breads (tortillas,
pita)
Patent Wheat Flours
High-gluten flour
• Generally from hard red spring wheat
• Highest in gluten-forming proteins
• Compared with bread flour:
– Higher water absorption
– Requires more mixing to fully develop
– Sometimes bromated
• Like bread flour:
– Unbleached or bleached
– Often contains malted barley flour
• Uses: bagels, thin crust pizzas, hard rolls
Patent Wheat Flours
Pastry flour
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From soft wheat
Low in gluten-forming proteins
Usually unbleached
Low water absorption
– High spread in cookie dough
• Uses: cookies, pie pastry dough, muffins, cakes
Patent Wheat Flours
Cake flour
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From soft wheat
Also called chlorinated or high-ratio flour
Stark white – highly bleached
Chlorine treatment:
– Increases water absorption, for thicker batters and
stiffer doughs
– Weakens gluten
• Uses: high-ratio cakes, cookies
Patent Wheat Flours
All-purpose flour
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From hard wheat, soft wheat, or blend
Also called H&R (hotel and restaurant) flour
Unbleached or bleached
Substitute with 60/40 or 50/50 blend of bread
flour and cake flour
• Uses: breads, cakes, cookies, muffins, pastries
Other Wheat Flours
Whole wheat flour
• From hard red wheat
– Whole wheat pastry flour is milled from soft wheat
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Also called graham or entire wheat flour
A whole grain
Many granulations available, from fine to coarse
Compared with white flour:
– Has higher absorption value; is a better drier
– Forms less gluten
– Baked goods are: denser, darker, stronger in flavor
Other Wheat Flours
Whole white wheat flour
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From white wheat; hard or soft
Golden (not white) in color
A whole grain
Compared with regular (red) whole wheat flour:
– Lighter in color
– Milder in taste
– Same amount of dietary fiber
Other Wheat Flours
Durum flour and durum semolina
• From endosperm of durum wheat
– Not whole grain
• Durum flour is fine; also called semolina flour.
• Durum semolina is coarse; looks like cornmeal.
• Compared with white flour:
– Yellow in color (high in carotenoids)
– Very high in protein
– Very hard kernel; hard to mill
• Uses: pasta, semolina bread
Functions of Flour
1. Providing structure
– Essential in many baked goods and pastries
• Holds size and shape of leavened baked goods;
prevents collapse.
• Provides thickening in pastry creams, pie fillings.
– From gluten, starches, and pentosan gums
• Gluten is important in pie crusts and crisp, dry
cookies.
• Starch is important in high-ratio cakes, muffins,
and cake-like brownies and cookies.
• Both important in yeast-raised breads.
Functions of Flour
2. Absorbing liquids
– Is a drier
• Absorption value of flour: amount of water
absorbed by flour when forming bread dough.
– From gluten, starches, and pentosan gums
• High-protein flours have higher absorption value
than low-protein flours.
– From protein, damaged starch granules, and pentosan
gums.
• Chlorinated cake flours have high absorption
value because of chlorine’s effects on starch
granules.
Functions of Flour
3. Contributing flavor
– Wheat: mild, nutty flavor
• Flours differ in flavor.
• Whole wheat flour: strongest flavor.
Functions of Flour
4. Contributing color
– From three sources
• Pigments in bran layer
– Red wheat bran is brown in color; white wheat is gold.
• Carotenoids in endosperm
– Durum wheat is highest in carotenoids; yellow in color.
– Carotenoids whiten when bleached.
• Maillard browning during baking
– High-protein flours typically brown more when baked
than low-protein flours.
Functions of Flour
5. Adding nutritional value
– Contribute starch, vitamins, minerals, and
protein.
• Protein in flour is low in lysine, an essential amino
acid.
– Whole wheat flour is better nutritionally than
white flour.
• Contains dietary fiber and many unidentified
health-promoting substances.
• Offers protection against certain diseases.
Storage of Flours
Flour has limited shelf life.
– Six months maximum.
– Oils oxidize when exposed to air.
• Develops rancid, cardboard-like off flavors,
– Whole wheat flour most susceptible.
• Bran and germ contain most of the oils in flour.
Storage of Flours
When storing flour:
– Rotate stock: practice FIFO (first in, first out).
– Do not add new flour to old.
– Cover bins and store in cool, dry area.
• Ideally, store wheat germ and bran under
refrigeration.
– Watch for infestation from insects and
rodents.
• Silky cobwebs are a sign of flour moths.
– Be especially vigilant with whole grains.
Words, Phrases, and Concepts
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Triticum grains
Cereal-free grains
Pumpernickel
Fermentation
tolerance
• Phytonutrients
• Degerminated
• Limewater
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Masa harina
Groats
Hull or husk
Lignan
Phytoestrogen
ALA omega-3 fatty
acid
• Mucilage
Introduction
Many variety grains are available to bakers.
– They vary in protein content.
– Most cannot form gluten.
• Exception: triticum grains
Introduction
Classification of variety grains and flours:
– Cereal grains and flours
• High in starch.
• Rye, corn, oats, rice, pearl millet, and teff
– Alternative wheat (triticum) grains and flours
• Spelt, Kamut, triticale, einkorn, emmer
– Cereal-free grains and flours
• Amaranth, buckwheat, flaxseed, potato, quinoa,
soy
Cereal Grains
Rye
– Traditionally grown in cold climates
• Russia, Eastern Europe, Scandinavia.
• Rye bread consumption high in these regions.
– Characteristically strong flavor.
– Oils oxidize easily, shortening flour’s shelf life.
– High in pentosan gums.
• Increases absorption value of flour.
• Important source of structure in rye dough.
– Rye bread formulas:
• Traditionally are sourdoughs.
• In North America, often include white (wheat) flour.
Cereal Grains
Rye
– Limited ability to form gluten.
– Bread doughs are easily overmixed and have
poor fermentation tolerance.
• Breads tend to be dense and gummy.
Cereal Grains
Rye
– Commercial grades:
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Light (white) rye: patent flour
Medium rye: clear flour
Dark rye: straight flour
Pumpernickel: whole rye flour
Cereal Grains
Corn
– Also called maize.
– Sold as flour, meal, or grits.
• The coarser the grain, the denser and crumblier
the baked good.
– White, yellow, or blue in color.
– Degerminated corn has oil-rich germ
removed.
• Milder flavor.
• Longer shelf life; less likely to oxidize.
• Enriched, to replace valuable vitamins and
minerals lost in germ removal.
Cereal Grains
Corn
– Forms no gluten.
– White (wheat) flour added to baked goods, to
provide structure and fermentation tolerance.
Cereal Grains
Corn
– Masa harina:
• Used in making corn tortillas.
• Dried corn is soaked in limewater (alkali).
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Softens corn kernels; easier to grind.
Removes bran layer.
Yellows the color and changes the flavor.
Increases availability of nutrients.
Cereal Grains
Oats
– Several products available: all are whole
grain.
• Made from dehulled whole oat kernels (groats).
– Quick-cooking rolled oats are cut thin; regular
rolled oats are coarser and chewier.
Cereal Grains
Oats
– Rolled oats are steamed, then flattened
between rollers.
• Softens and precooks oats.
• Prevents rancid oil off-flavors from developing.
– Inactivates lipase enzymes.
– Contain the gum beta-glucan.
• Gluey, gummy consistency.
• Source of soluble dietary fiber.
– Commonly used in cookies, streusel toppings,
muffins, breads.
Cereal Grains
Rice
– Different varieties and types
• Long-grain rice
– Holds its shape well, especially if par-boiled.
• Medium or short grain rice
– Cooks into creamy, clingy texture.
• Brown rice is a whole grain
– Takes longer to cook; has a chewy texture.
– Use: rice puddings, custards, pies
Cereal Grains
Rice flour
– Uses: gluten-free baked goods; Middle
Eastern and Asian cakes and cookies.
– Medium and short-grain white or brown:
• Best for gluten-free baked goods.
– Long grain:
• Best for dry, sandy cookies, like shortbread.
– Also available: rice starch flour.
• Purified rice starch (protein, etc. removed),
pulverized into flour.
Cereal Grains
Pearl millet
– Grown in Africa and India.
– Tiny tear-shaped grains that pop like popcorn.
– Must be cooked in water to soften.
– Millet flour used in India in roti (flatbread).
Teff
– Grown in Ethiopia (in Eastern Africa)
– Tiniest of cereal grains.
– Teff flour used in a sour, spongy pancake
called injera .
Alternative Wheat Grains
Spelt
– Like all triticum (wheat) grains, not appropriate
for wheat-free or gluten-free diets.
– Ancestor of modern wheat.
– Has close-fitting protective inedible husk (hull).
• Difficult to harvest: kernels do not fall out easily.
• Easier to grow organically: kernels are protected
from insects and microorganisms.
– Grown as specialty or health food.
– Forms weak gluten that is easily overworked.
– Use in place of soft wheat flour.
Alternative Wheat Grains
Kamut
– Ancestor of modern durum wheat; high in
protein.
– Name is trademarked; licensed to those
growing the grain organically.
– Large kernels.
• Two-three times size of regular wheat kernels.
• Mild-tasting.
– Uses: whole grain pasta, bread, bulgur,
couscous.
Alternative Wheat Grains
Triticale
– Cross between wheat and rye
– Superior nutritional quality compared to
wheat.
– Use instead of soft wheat.
Einkorn and Emmer (Farro)
– Ancient; over 10,000 years old.
– Close-fitting inedible husk; easy to grow
organically.
– Einkorn: soft, sticky dough; Emmer: heavytextured bread.
Cereal-Free Grains and Flours
Amaranth
– Small, light-brown seeds from herb grown in
Central and South America.
– Unlike wheat and most cereal grains, high in
lysine, an essential amino acid.
– Uses: multi-grain breads; pops like popcorn.
Cereal-Free Grains and Flours
Buckwheat
– Not wheat; forms no gluten.
– Has strong flavor and dark color; often
blended with white (wheat) flour.
– Sold as:
• Coarse grits.
• Finely ground flour, whole grain or not.
• Whole kernels, roasted; called kasha.
– Uses: Russian pancakes (blini), Breton
crêpes from north of France, Japanese soba
noodles.
Cereal-Free Grains and Flours
Flaxseed
– Small, hard, dark oval oily seeds.
– Prized for its nutritional benefits:
• Soluble dietary fiber from gummy mucilage.
• Lignan, an antioxidant phytoestrogen.
• ALA omega-3 fatty acid
– Grind in blender or food processor before use.
• Nutritional benefits available only when ground.
• Refrigerate ground seeds, to minimize rancidity.
– Uses: add to batters and doughs for health
benefits.
Cereal-Free Grains and Flours
Potato
– Tuber (root), not grain.
– Cooked and dried, then cut into flakes or
milled into flour.
• Cooked (gelatinized) starch is easily broken down
into sugars by amylase.
• Increases water absorption of doughs; improves
fermentation.
– Uses: soft, moist yeast breads.
– Also available: potato starch flour.
• Highly purified; protein, etc. removed.
Cereal-Free Grains and Flours
Quinoa
– Small, round seeds.
– High in healthful unsaturated fatty acids.
• Oxidizes easily; refrigerate ground quinoa.
– Like amaranth,
• Grows in South America.
• High in lysine, an essential amino acid.
– Uses: multi-grain breads.
Cereal-Free Grains and Flours
Soy
– Oily legume; not a cereal grain or seed.
– Very high in protein and fat, low in starch.
– Defatted (fat removed) for use in baking.
– Two types:
• Untoasted; acts as a bleaching and maturing agent
from active enzymes.
• Toasted; excellent source of nutritionally highquality protein and other nutrients.
– Uses: yeast doughs; milk and egg substitutes
in various products
Lab
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Each GroupCompare grains
Water absorption
Gr 1: Bread
Gr 2: Whole wheat
Gr 3: Cake
Gr 4: High gluten