CHAPTER 5: WHEAT FLOUR Flashcards
Is wheat a cereal grain?
Yes
Name four other cereal grains.
Corn (maize), oats, rice and rye.
Widespread consumption of cereal grains began when and where?
Middle East about 10,000 years ago, when agriculture first began. It was then that wheat was first planted and cultivated.
Are thousands of different wheat varieties grown throughout the world?
Yes
What parts of North America have ideal conditions for wheat?
Midwest and southern prairie region of Canada.
Name four other major wheat growing countries.
China (more than everyone), India, France, and Russia.
Most popular cereal grain used in baked goods.
Wheat
Where does wheat’s popularity stem from?
The gluten that forms when flour is mixed with water. Also preferred for its mild, nutty flavor.
Are wheat kernels seeds of the wheat plant?
Yes
What part of the wheat plant is illdd into flour?
Kernel
Are cereal grains in the grass family?
Yes
When a field of wheat starts to grow what does it look like?
A lawn of grass.
Three main parts of a wheat kernel.
Endosperm, germ and bran.
What is white flour milled from?
The endosperm.
Why is wheat flour considered a whole wheat product?
It contains the entire wheat kernel.
What makes up the largest part of a wheat kernel?
Endosperm is about 80%.
Why is endosperm so white?
Because it contains mostly starch, around 70 to 75%.
The starch of an endosperm is tightly packed into starch granules, which are embedded in what?
Chunks of protein.
Two important proteins in the endosperm are what?
Glutenin and gliadin.
Wheat is the only cereal grain that contains sufficient what? For what?
Glutenin and gliadin for good quality formation of gluten in bread making.
What is the embryo of the wheat plant?
The germ.
What part of the wheat plant germinates given the right conditions?
Germ
How much of the kernel is made up of wheat germ?
2.5%
What percent of protein is the germ?
25%
Wheat germ is high in protein and…
fat, B vitamins, vitamin E and minerals; all important to the germ as it sprouts.
Does germ protein form gluten?
No
Can wheat germ be purchased and added to goods?
Yes
How is wheat germ typically sold?
Toasted
What does toasting do to wheat germ?
Adds a nutty flavor and destroys enzymes called lipases, present in wheat germ that break down oils and cause them to oxidize.
What wheat gym contribute to the structure of baked goods?
No
Why is wheat germ typically added as an ingredient?
Its nutritional value.
Why store wheat germ in the refrigerator?
It’s high in polyunsaturated oils that oxidize easily.
What is the bran?
Protective outer layer covering the wheat kernel.
Is the bran usually darker than the endosperm?
Yes, much darker; white wheat, which has a lighter color, is also available.
What is bran high in?
Dietary fiber.
Bran is about what percent fiber? What kind of fiber?
42% insoluble fiber.
Percentage of protein in bran.
15%
Is bran high in protein, fat, vitamins and minerals?
Yes
Do bran protein form gluten?
No
Do wheat germ and bran interfere with gluten development?
Yes
How can whet bran be purchased?
As small flakes.
Does bran change during the baking process?
While it may soften slightly, bran remains relatively unchanged.
Is bran a moistener or a drier?
Neither
Besides nutritional value, what does bran add to baking?
A dark, rustic appearance and distinct nutty flavor.
Are dark colored products all whole grain?
Not necessarily. often, molasses or caramel coloring is added to baked goods to give them a heartier look.
Do products like seven-grain bread or stone-ground flour guarantee a whole grain product?
No
What is dietary fiber?
Plant matter that humans cannot digest. Classified as soluble of insoluble.
What is soluble fiber?
Fiber that will thicken or form a gel when placed in water.
What is insoluble fiber?
Fiber that will sink or float in water but remains essentially unchanged because it does not absorb what.
What does insoluble fiber do for the body?
Improves intestinal health and is thought to reduce the risks of certain cancers.
What does soluble fiber do for the body?
Lowers blood cholesterol and can reduce the risk of heart disease.
Do fibrous foods have a fibrous texture?
Not necessarily.
How are proteins fibrous but not?
There fibers consist of fully digestible proteins and are not dietary fiber.
Is cocoa powder a source of fiber?
Yes
White flour contains mostly what?
Starch
Does bread flour, considered lower in starch than regular flour, contain mostly starch?
Yes
Are some starch granules damaged during the milling process? How does relate to amylase and fermentation?
Yes, they are also damage when stored under damp conditions. When this happens, starch can be broken down by the enzyme amylase into sugars that are readily fermented by yeast.
The amount of sugar naturally present in flour as a %?
Less than 0.5%.
Is the amount of naturally accruing sugar in flour enough for yeast fermentation?
Rarely, which is why most yeast dough formulas include at least some sugar or source of amylase.
Flour is made up mostly of what two things?
Starch and protein.
Starch makes up the bulk of flour. It’s usually between what percentage?
68 to 76%
Chunks of proteins usually make up what % of flour?
6 to 18%
What acts as the cement that holds starch granules together in the endosperm?
Chunks of protein.
Glutenin and gliadin make up what % of protein in the endosperm?
80%
Besides protein and starch, what else is in flour?
14% moisture, 2% gums, 1% lipids and 0.5% ash.
What other proteins (besides gluten in and gliadin) are found in white flour?
Enzymes such as amylase, protease and lipase.
Moisture in flour typically ranges in what %?
11 to 14%
What happens when moisture content in flour rises above 14%?
Flour is susceptible to fungus and mold growth, flavor changes, enzyme activity, and insect infestation.
How must flour be stored?
Covered in a cool, dry place.
Other carbohydrates in flour besides starch include what? What’s their %?
Gums are between 2 and 3%, primarily pentosans.
Why are pentosans an important part of white flour?
They are present in relatively low levels but make a large contribution to water absorption; absorb 10x their weight in water. They also increase the viscosity or consistency or consistency of batters and doughs.
What happens if you have large amounts of pentosan?
They result in a lower volume of baked goods.
Is pentosan a good source of soluble fiber?
Yes
Percentage of lipids.
1 to 1.5%
Are lipids in flour important for proper gluten development?
Yes
Is stale flour dangerous?
No, it just has a distinct cardboard flavor.
What is ash composed of?
Inorganic matter–mineral salts–naturally present in wheat kernels.
Besides providing minerals, ash increases what? How?
Yeast fermentation by contributing minerals to yeast.
Does ash have a grey color that is carried over to flour?
Yes
What % of flour is ash?
Less than 0.6%
Where is ash concentrated?
The bran layer.
How is ash measured in white flour?
Burning flour and grain samples at a very high temp–over 1,000ºF (538ºC)–and weighing the remains.
What is present in white flour that gives it the creamy, off-white color?
Carotenoid pigments present in extremely low amounts (1-4 parts per million).
Is carotenoid in the same family as beta-carotene?
Yes, the orange pigment for carrots.
Bakers generally classify wheat by what?
The hardness of the kernel, that is, whether it feels hard or soft to the touch.
Hard whet kernels are high in what?
Protein
Soft wheat kernels are low in what?
Protein
As the amount of protein in flour increases, what happens to starch?
It decreases.
Why do hard wheat kernels feels harder than soft ones?
Protein in these kernels forms large, hard chunks that hold tightly to starch granules.
Are hard wheat kernels generally higher in carotenoids and water-grabbing pentosans?
Yes
Carotenoid pigments provide a creamy, off-white color to what?
Unbleached flour
What type of flour forms high-quality gluten?
Hard wheat flours.
Because they form strong gluten, hard wheat flours are considered what?
Strong flours.
What is said about strong flours water absorption mixing time to develop gluten?
They usually have a high water-absorption value and require a longer mixing time to fully develop, but they are tolerant of over-mixing.
Besides hardness of the kernel, how else can wheat be classified?
Its botanical species, the time of year it’s planted or grown, or by the color of the kernel.
Six major classes of wheat in the US are described as what?
Hard red winter, soft red winter, hard red spring, hard white, soft white, and durum.
Except for durum (Triticum durum), most wheats milled in the North America are what?
Varieties of so-called common wheat (Triticum aestivum).
Can the quality of flour within any of the categories vary greatly? Explain.
Yes. In particular, geographic, climatic, and soil variation affect composition and quality of wheat.
Why do millers typically blend flours from different regions?
To provide consistent product year after year.
Do strong flours require more mixing to fully develop gluten?
Yes
Are flours milled from soft wheat kernels whiter and finer to the touch than hard wheat flour?
Yes
Strong flours are typically used for what?
Yeast-raised products, such as breads, rolls, croissants, and Danish.
Why do soft wheat flours tend to pack together when squeezed and don’t flow or dust a bench easily?
Because they are so much finer than hard wheat.
Do soft wheat flours typically form weak gluten that tears easily?
Yes
Soft wheat flours are sometimes called what?
Weak flours
Weak flour is desirable for what?
Many cakes, cookies and pastries.
Can wheat and other cereal grains be milled into many different forms? Examples.
Yes, from very fine flour to cracked or whole kernels.
Do small, fine particles absorb water faster than larger ones?
Yes
Do whole cracked kernels and coarse meals and flakes often require soaking or gentle heating before use?
Yes, to allow for proper absorption and softening.
Why are larger kernels good for diabetics?
It takes the longer to be broken down by the body; easier to control blood glucose levels.
Flours by definition are what?
Grains milled to a relatively fine granulation size.
Do all flour have the same granulation? Example.
No, soft wheat flours are usually ground finer than hard wheat because the softness of their kernels allows it.
Are granular products coarser than flour?
Yes
Can granular products be whole grain?
Yes, like flour, if they are milled from the whole kernel, or not, if milled from the endosperm.
Two examples of granular wheat products.
Semolina and farina.
What is coarsely ground from the endosperm of hard red wheat, farina or semolina?
Farina
What is Cream of Wheat an example of?
Farina
Durum semolina is coarsely ground from what?
Endosperm of durum wheat.
Because durum semolina is yellow in cooler, it’s often mistaken for what?
Cornmeal
Can grains be purchased as whole kernels? What are they generally called?
Yes, wheat berries.
What do whole kernels add to bread?
Contrasting crunchy texture and visual appeal.
Do millers often put small amounts of additives in flour?
Yes
Are the types and amounts of additives strictly regulated by the gov’t?
Yes, by law, millers must label flour with the additives it contains.
Are some additives required by law?
Yes
Why is white flour enriched?
Bran and germ are removed from the endosperm during the milling process; several vitamins, minerals, dietary fiber, protein and fat are removed. Enrichment replaces certain vitamins and minerals that were lost.
What is not given back during the enrichment process?
Dietary fiber in the bran, protein in the germ.
When did flour enrichment begin? What did it eliminate?
In the early 1940s after gov’t surveys found that high incidence of disease was caused by certain vitamin and mineral deficiencies. This virtually eliminated two of these diseases, beriberi and pellagra.
Do the US and Canada periodically evaluate nutritional needs? What happened in 1990? Why?
Yes, and they found that folic acid needed to be added; Folic acid prevents certain birth defects, including spine bifida, and can reduce the risk of coronary heart disease.
What vitamins and minerals are added to white flour?
Iron and B vitamins (thiamin, riboflavin, niacin, folic acid) in amounts greater than or equal to whole wheat flour. Certain other vitamins and minerals are optional.
Essentially, are all baked goods and pasta products made from white flour in North America enriched?
Yes
Natural aging occurs when freshly milled green flour is exposed to what?
Air for several weeks.
Why does air do to flour?
First, it whitens flour. Second, it strengthens the gluten that forms from flour.
In naturally aging flour, what is added?
Air
The active ingredient in air is what?
Oxygen, which is considered an oxidizing agent.
How does oxygen change the color of flour?
Oxygen oxidizes the carotenoid pigment in flour, changing their chemical structure and whitening them.
How does oxygen strengthen gluten?
Maturing agents that strengthen gluten simulate natural aging; they oxidize portions of glutenin and gliadin molecules, altering them so that more bonds form when gluten forms.
Why are yeast doughs made with aged flour easier to handle than those made with green flour?
Doughs with stronger gluten are less sticky and less likely to tear when stretched.
What happens to the final product when bread is made with a stronger gluten?
It yields a finer crumb and more volume.
Disadvantages of natural aging.
First, it requires time, often several weeks or months; flour takes up valuable silo space and isn’t paying the bills. Plus it’s likely to support mold growth or become infested with insects. It’s also inconsistent, and not as effective as many chemical bleaching and maturing agents.
Naturally aged flours are often labeled what?
Unbleached
What are maturing agents?
Additives that change the baking properties of flours.
Who adds maturing agents?
The miller or are found in many dough conditioners by the baker.
Do all maturing agents strengthen gluten?
No, some weaken it.
Why can the term “maturing agent” be confusing?
It is used to describe additives that have completely opposite functions.
Do potassium bromate and ascorbic acid strengthen or weaken gluten?
Strengthen
What amount of maturing agents are needed to get desired changes?
A small amount, only a few parts per million.
When potassium bromate is added to flour, it is said to be what?
Bromated
What’s the standard against which all other maturing agents are judged?
Potassium bromate
How long has potassium bromate been around?
Since the early 1900s.
Why is potassium bromate no longer allowed as a flour additive in Canada and Europe? What’s up with the US?
PB is considered a carcinogen because it has been shown to cause cancer in laboratory animals. While still approved in the US, it’s slowly diminishing, and much lower levels are added today than previously.
In California, what maturing agent must carry a warning label?
Potassium bromate
What’s another name for ascorbic acid?
Vitamin C
Is ascorbic acid one of the most popular maturing agents?
It is becoming one because of potassium bromates decreased usage even though it’s not as effective.
Do bleaching agents whiten carotenoids?
Yes
Name two common flour bleaching agents.
Benzoyl peroxide and chlorine gas.
Why is benzoyl peroxide used in all types of flour?
It’s extremely effective at whitening and produces no maturing effects.
Benzoyl peroxide is commonly used in what types of flour?
bread, high-gluten, AP, cake and pastry flours that are bleached.
Chlorine is used in what flour?
Cake flour only.
Why is chlorine great with cake flour?
It improves baking properties of soft wheat flour by substantially weakening gluten and by allowing starch to absorb water more quickly and easily.
Can you always tell whether flour has been bleached on the label? What can’t you tell?
Yes, but you can’t necessarily tell what bleaching agent was used. Ask the manufacturer if you would like to know.
Explain why using maturing agents to strengthen gluten is a good thing - be detailed.
The more bonds there are, the stronger, drier, and more cohesive a dough. When gas expands during final proof and the oven spring, the stronger gluten stretches better without breaking. Loaf volume is higher and grain is less coarse.
Are many maturing agents more effective than natural aging?
Yes
For the most part, do maturing agents that strengthen also whiten flour?
No, they mostly don’t.
Do potassium bromate and bromate replacers work at different times in baking? How does this affect commercial dough conditioners?
Yes, this is why commercial dough conditioners often contain a combination of maturing agents to strengthen dough throughout the process.
