Cereals and Grains Flashcards
What parts of the seed is edible?
Grain, kernel, berry
What are the most common grains?
1) Corn
2) Rice
3) Wheat
4) Barley
What is the function of the husk?
protective covering; usually not consumed
What is the function of bran? What is it a good source of?
protects the endosperm; excellent source of fiber and minerals
What is the underneath bran called? What is it a good source of?
- Aleurone layer: less fibrous coating
- contains protein, phosphorus, B vitamins (thiamin), some fat, antioxidants
Which layers are removed during processing of white flour?
Bran and aleurone
Husk and germ
Which part of the grain is the largest and is the basis of all flours?
Endosperm
What does the endosperm contain?
contains mostly carbohydrates, some protein and small amounts of vitamins, minerals and fiber
Which part of the grain is the smallest?
Germ (embryo)
What does the germ (embryo) contain?
rich in fat and contains some incomplete protein, vitamins (B vitamins, vitamin E) and minerals
Protein is generally higher in which grain?
Wheat
Grains are an incomplete protein. What are they lacking? Why should you pair with legumes?
- Lack in lysine, adequate methionine
- Legumes lack methionine, have sufficient lysine
= complete protein
The majority of lipids in grains are what?
Omega-6 PUFA
Which vitamins are contained in grains?
B vitamins: thiamin (B1), riboflavin (B2), niacin (B3), vitamin B6, pantothenic acid (B5), folate (B9); Vitamin E
Which minerals are contained in grains?
◦ Varies by type of grain
◦ Fe,Mg,P,K,Cu,Mn,Se
Where is fiber found in grains?
Bran and endosperm
What kinds of fibers are contained in grains?
cellulose, hemicellulose, lignin, inulin, resistant starch
Name some notable phytochemicals in grains.
phenolic compounds, carotenoids, vitamin E compounds, lignans, β- glucan, inulin and phytosterols
Where are the highest levels of phytochemicals in grains?
Bran and aleurone = highest
germ too
How does processing affect the phytochemicals in grains?
Decreases content but may increase bioavailibility
What is white refined flour composed of?
- Endosperm
- Husk bran and germ are REMOVED
Which nutrients are added to fortify white flour?
Thiamin (B1), Riboflavin (B2), Niacin (B3), Iron, Folate
They are enriched to a level equal or higher than that found in whole grains
Define enrichment.
replacement of nutrients to levels that existed before processing of the whole grains
Define fortification.
addition of nutrient to levels higher than those which existed before processing
What are Canada’s Food Guide recommendations for grains?
- 1/2 grains = whole
- Eat a variety of grains
- Choose products that are lower in fat, sugar and salt
What is not removed to make a product whole grain?
Bran is NOT removed
What is the chemical structure of a starch?
Complex CHO
Polymer of alpha-D-glucose
How is starch used in plants? Where is it stored?
Used for energy or stored in seeds, roots, stems or tubers
What do we use starches for?
◦ Thickeners, stabilizers, texturizers, bind water or fat
◦ Fat substitutes, emulsifiers
◦ Contribute to texture, taste and appearance!
What are the two distinct types of starches?
Amylose and amylopectin
What grains contain higher amount of amylose?
Corn and wheat flour
How is amylose in its natural state?
Coiled up into helix (H-bonding)
What is amylose?
A linear chain (500-2000) of alpha-D-glucose molecules linked by glycosidic bond between carbon 1(aldehyde group) and 4 (hydroxyl group)
What is amylopectin?
A highly branched molecule that consists of relatively short chains of alpha- D-glucose units linked 1-4
Where does the branching structure of amylopectin chains join together?
Through carbon atoms 1 and 6
Compare the shape of amylopectin and amylose.
amylopectin is larger than amylose but amylopectin is more bushy and compact in shape
Which grain contains 100% amylopectin?
Waxy maize
Define gelatinization.
happens when starch granules are heated in the presence of a liquid
How does gelatinization happen?
- Heat causes H-bonds to weaken – ↑ solubility •Water infiltrate the starch granule
- Granule swells to peak thickness
- Volume, viscosity and translucency increases
Define gelation?
occurs after gelatinization; aka: gelation
What product is a good gelling agent?
Cornstarch
How does gel formation occur?
•Fluid starch paste (sol) cools •H-bonds reform & water is trapped •Semisolid paste forms (gel)
Define retrogradation. How is it accelerated?
- leakage/separation of liquid from the gel after a long standing time
- Freezing
How does retrogradation occur?
- Gel cools further
* H-bonds tighten between amylose molecules •Water is squeezed out -> syneresis
Name some factors that influence gelatinization.
◦ Water ◦ Temperature ◦ Timing ◦ Stirring ◦ Acid ◦ Sugar ◦ Fat/Protein
Compare resistant and modified starches.
Resistant: not digested by the small intestine
Modified: altered to extend their usefulness in the food industry and
food processing
Where are resistant starches found?
high amylose maize, some potatoes and green banana
What are regraded starches? How do they act?
gelatinized starches that have undergone retrogradation - resists dispersion in water and digestion by α-amylase.
How are starches modified? Give examples.
◦ Gelatinization ability, heating times, freezing stability, cold-water solubility or viscosity
◦ Examples: cross-linked starch, oxidized starch, pregelatinized (instant) starch
How are starches used in food products?
◦ Thickeners or gelling agent ◦ Edible film
◦ Sweetener: dextrose, syrups ◦ Stabilizer
◦ Texturizer
◦ Water or fat binders ◦ Fat substitutes
◦ Emulsification aids
What is triticale?
Wheat and rye hybrid
Name some commonly known cereals
Wheat, barley, oats, rice, maize, wheat
Which cereal has the highest amount of fiber? Protein? Fat?
Fiber: barley
Protein: oats
Fat: oats
Define pseudocereals.
◦ not ”true cereals” – they do not belong to the Poaceae family.
◦ Many are not even grains, but rather seeds from plants that are not grasses.
◦ They have a similar nutritional makeup and are used in similar ways.
Name 3 pseudocereals.
Buckwheat, amaranth, quinoa
What are all 3 pseudocereals excellent sources of?
Magnesium and Manganese
Which pseudocereal is an excellent source of copper? Of folate?
Copper: buckwheat
Folate: quinoa
Which pseudocereal has 50% DV of manganese in a serving?
Amaranth
What is gluten?
Gluten is a protein found in wheat and related “grass” plants
What are the two main fractions of gluten?
- Gliadins (soluble)
* Glutenins (insoluble)
How does gluten play a key role in baking?
- elasticity, viscosity and cohesiveness of the dough
- Allows dough to hold gas when it rises. CO2 molecules produced by yeast become Trapped, creating a fluffy texture.
Name some gluten-containing grains.
◦ Wheat ◦ Bulgur ◦ Spelt ◦ Barley ◦Rye ◦Triticale (wheat & rye hybrid)
Name some gluten-free grains.
◦ The Pseudocereals ◦ Oats** ◦ Cornmeal ◦ Millet ◦ Rice ◦ Teff
Why shouldn’t people eat gluten-free products if they don’t have gluten sensitivities?
◦ GF products often contain more fat and sugar
◦ Many are not fortified (unlike wheat)
◦ Generally more expensive
Name the 3 primary gluten replacers.
- Xantham Gum
- Guar Gum
- Ground seeds (psyllium, flax, chia)
Which gluten replacer is the best?
Xantham gum, excellent binding and structure building capabilities with good elasticity
How does guar gum compare to xantham gum?
Good binding and structure, but less elasticity than
xantham gum
Why aren’t ground seeds a perfect gluten replacer?
Looks right, but taste is different and texture changes with time
Name some products with hidden gluten.
◦ Soy sauce ◦ Spices ◦ Soup Broths ◦ Prepared sauces ◦ Sausages & prepared meats (meat fillers, breadcrumbs) ◦ Chocolate (Lindt – malt barley)? ◦ Beer ◦ Cosmetics!
Name the 3 kinds of gluten sensitivities.
◦Celiac Disease
◦Non-Celiac Gluten Sensitivity (NCGS) ◦Wheat allergy**
What % of the Canadian population is affected by Celiac’s disease?
1%
What happens in Celiac’s disease?
the immune system of a celiac reacts negatively to the presence of gluten in the diet causing damage to the inner lining of the small bowel which reduces the person’s ability to absorb nutrients
Which nutrients are less absorbed in an individual with Celiac’s?
iron, folate, calcium, Vitamin D, protein, fat
and other food compounds
What are the symptoms of Celiac’s disease?
Vary and can be extra-intestinal including but not restricted to: abdominal pain, flatulence, diarrhea, mouth ulcers, bone pain, fatigue, headaches
How is Celiac’s disease diagnosed?
Blood tests or small bowel biopsy
What is the treatment for Celiac’s?
Eliminating all sources of gluten
What is Non-Celiac Gluten Sensitivity? How does it compare to Celiac’s?
individuals who cannot tolerate gluten and experience symptoms
similar to those with celiac disease but yet who lack the same
antibodies and intestinal damage as seen in celiac disease.
How do the symptoms of NCGS compare to Celiac’s?
similar to celiac disease however some research shows that symptoms are predominantly extra-intestinal (ex: ”foggy” mind, joint pain…)
How is NCGS diagnosed?
By excluding Celiac disease
What is the treatment of NCGS?
Eliminating all source of gluten
What is a wheat allergy? What is it mediated by?
◦ Is an allergic reaction mediated by IgE antibodies
◦ It is an allergy to any of the hundreds of proteins in wheat, and
not to gluten
How is a wheat allergy diagnosed?
◦ “Diagnosis is made through skin prick tests, wheat-specific IgE blood testing and a food challenge”
Which form of arsenic is the more toxic form?
The inorganic form, arsenic is found in both forms in the environment
What toxic substance does rice contain?
Arsenic
Brown rice has the most
Basmati rice has the least
Still do not pose a health risk
Should you rinse rice?
It gets rid of arsenic, but also of iron, niacin, thiamine and folate
How should you store dry grains? How long?
best stored in an airtight container, in a cool dry area
6-12 months
What is the biggest contributor to deterioration of grains?
Moisture
Should you freeze grains?
No, alters protein structure affecting baking qualitites
How should you store cooked grains? How long do they last?
are best stored in airtight containers in the refrigerator
Up to 7 days
Can also be frozen if stored in airtight containers
Where can infestation of pantry pests occur?
◦ The processing plant
◦ The warehouse
◦ On the delivery vehicle ◦ At the retail store
Name 3 ways to control infestation of pantry pests?
◦ Eliminating source of infestation (identifying and eliminating infested food)
◦ Remove any spilled food stuff by regularly vacuuming and washing pantry shelves, cupboards, floors…
◦ Store cereal grains in airtight plastic containers or glass jars, in a cool dry place
After wheat, the second most common grain used in bread making is?
Rye
Most of the vitamin E in grains is found in what portion of the kernel?
Germ
The endosperm of grain is primarily made of?
Starch
Malt is made from germinated (sprouted) ______
Barley
Which type of wheat is best for producing cake flour?
Soft
Are gliadins soluble or insoluble?
Soluble
Are glutenins soluble or insoluble?
Insoluble
The endosperm makes up ____% of the grain.
83%
The bran makes up ____% of the grain.
14.5%
The germ makes up ____% of the grain.
2.5%
