TLE COOKERY 10 Lesson 2 LO1 PREPARE CEREAL & STARCH Sources of Starch
Summary
TLDRThe video lesson focuses on the preparation of cereals and starch dishes, highlighting sources of starch from plants, including cereal grains, roots, and tubers. It explains the types and classifications of starchesโnative, modified, and purified. The lesson covers the molecular structure of starch, including amylose and amylopectin, and their roles in cooking. Key reactions such as gelatinization, retrogradation, and dextrinization are discussed, along with the functional properties of starch in food preparation. It emphasizes the nutritional value of cereals and their importance in a balanced diet.
Takeaways
- ๐พ The main sources of starch come from seeds, roots, and tubers, including cereal grains (corn, wheat, rice, etc.) and tubers like potatoes and cassava.
- ๐งฌ Starches are composed of two fractions: amylose (contributes to gelling) and amylopectin (contributes to thickening).
- ๐ฅ Starches can be classified into native starches (naturally derived), modified starches (chemically altered), and purified starches (separated by wet milling).
- ๐ Native starches are found naturally in plants, while modified starches are chemically altered to change their properties.
- ๐ฌ Starch molecules are polysaccharides made up of glucose molecules. The organization of these molecules in starch granules creates crystalline patterns observed under polarized light.
- ๐ฎ Gelatinization is the process where starch granules swell and absorb water, increasing viscosity as starch breaks down when heated.
- ๐ฏ Sugar influences the gelatinization process by competing for water, which affects the texture and structure of starch-based foods.
- ๐ฝ๏ธ Starch has many functional roles in food, such as acting as a thickener, binder, stabilizer, moisture retainer, and fat substitute in processed foods.
- ๐ Dextrinization is the process where starches break down into dextrins during dry roasting or heating, such as in toasted bread or sauces.
- ๐พ Cereals, especially whole grains, provide essential nutrients like carbohydrates, proteins, fats, vitamins, and minerals, and enriched cereals offer added vitamins and minerals.
Q & A
What are the common sources of food starch?
-The common sources of food starch include cereal grains such as corn, wheat, rice, sorghum, and oats, as well as roots and tubers like potatoes, sweet potatoes, arrowroot, and cassava (tapioca).
What is the difference between native starch and modified starch?
-Native starch refers to starch as it is naturally derived from its plant source, while modified starch has been altered physically or chemically to change its key chemical or physical properties.
How is purified starch obtained?
-Purified starch is obtained from grains and tubers through a process called wet milling, which uses grinding, screening, and centrifuging to separate starch from fiber, oil, and protein.
What are the two main fractions of starch molecules?
-The two main fractions of starch molecules are amylose, a long chain-like structure responsible for gelling characteristics, and amylopectin, a highly branched molecule that contributes thickening properties but does not form a gel.
How do starch granules behave when heated in water?
-When heated in water, starch granules undergo gelatinization, where they absorb water, swell, and disrupt their organized structure, increasing the mixtureโs viscosity.
What is retrogradation in the context of starch?
-Retrogradation is the process where starch molecules, particularly amylose, reassociate into an ordered structure after gelatinization, resulting in a crystalline texture.
What is dextrinization, and how is it achieved?
-Dextrinization is the process of forming dextrins, which are partially hydrolyzed starches. It is typically achieved by dry roasting starches, such as toasting flour or bread.
How does sugar affect starch gelatinization?
-Sugar influences the temperature and rate of gelatinization by competing with starch for water, which can slow down or alter the process.
What are the functional roles of starch in food?
-Starch functions as a thickener, moisture retainer, binder, stabilizer, and fat substitute in foods. It is used in products like gravies, sauces, processed meats, and puddings.
What nutritional value do cereals provide?
-Cereals provide carbohydrates, protein, fats, vitamins, minerals, water, and cellulose. Whole grains, in particular, are important for a balanced diet and contribute valuable nutrients like thiamine, niacin, riboflavin, and iron.
Outlines
๐พ Introduction to Starches and Their Sources
This paragraph introduces the lesson on cereals and starch dishes. It explains that starch is mainly found in seeds, roots, and tubers, with common sources being cereal grains like corn, wheat, and rice, as well as tubers such as potatoes, sweet potatoes, and cassava. The paragraph also distinguishes between different types of starches based on their plant sources, and introduces native or natural starches, modified starches, and purified starches, discussing their methods of processing and uses in food preparation.
๐ฌ Starch Composition and Molecular Structure
This section delves into the composition and structure of starch molecules. It explains that starch is a polysaccharide made of glucose molecules, and it contains two main fractions: amylose, which has a linear structure and contributes to gelling properties, and amylopectin, which has a branched structure and affects the thickness of starch mixtures. The paragraph also discusses the role of these molecules in the formation of starch granules and their physical characteristics, such as their arrangement in plants and the phenomenon of birefringence when observed under polarized light.
๐ฅ Properties and Reactions of Starch
This paragraph explores the various reactions and properties of starch when subjected to different processes. It explains gelatinization, the swelling of starch granules when heated in water, and how viscosity increases as more starch molecules break down. It also introduces retrogradation, the reordering of starch molecules after gelatinization, and dextrinization, the process of forming dextrins through roasting. The paragraph also covers hydrolysis, which occurs during cooking or chemical reactions involving water, and how it affects the viscosity and texture of food.
๐ Functional Properties and Uses of Starch
The final paragraph outlines the functional roles of starch in food preparation, including its use as a thickener, colloidal stabilizer, moisture retainer, and fat substitute. Starch also enhances the flavor and texture of processed meats and serves as a binder and filler in foods like hot dogs and sausages. The section emphasizes the nutritional value of cereals, particularly whole grains, which provide essential vitamins and minerals, and advocates for including at least four servings of grains in a daily diet. It concludes by highlighting the importance of enriched and restored cereals as nutrient-dense food options.
Mindmap
Keywords
๐กStarch
๐กAmylose
๐กAmylopectin
๐กGelatinization
๐กRetrogradation
๐กCereals
๐กModified Starch
๐กDextrinization
๐กSyneresis
๐กHydrolysis
Highlights
The parts of plants that store most starch are seeds, roots, and tubers. Common sources include cereal grains like corn, wheat, rice, sorghum, and oats, as well as roots like potatoes and tropical cassava.
Starches are named after their plant sources: corn starch from corn, rice starch from rice, and tapioca from cassava.
Native or natural starches refer to starches as originally derived from their plant source, whereas modified starches are chemically or physically altered to change properties.
Purified starch is separated from grains and tubers by a process called wet milling, which uses grinding, screening, and centrifuging techniques.
Starch is a polysaccharide made of hundreds or thousands of glucose molecules. The two main types of starch molecules are amylose and amylopectin.
Amylose is a linear molecule that contributes to gelling characteristics in cooked and cold starch mixtures.
Amylopectin has a branched structure and contributes to thickening properties when starch is cooked in water, though it does not form a gel.
Most natural starches are mixtures of amylose and amylopectin. Cereal starches contain higher amylose content than root starches like tapioca and potato.
The starch granule has a crystalline-like structure observed under polarized light. This phenomenon is called birefringence, which disappears when the starch is heated.
Gelatinization is the process of starch granules swelling as they absorb water, causing changes in their structure during heating.
Viscosity increases as gelatinized starches break and release more molecules, thickening the mixture.
Retrogradation occurs when starch molecules, particularly amylose, reassociate into a crystalline structure after being disrupted by gelatinization.
Dextrinization is the process of forming dextrins by dry roasting starches, commonly seen in toasting bread or flour.
Starches act as thickeners, stabilizers, moisture retainers, binders, and fat substitutes in various food products like gravies, sauces, processed meats, and sausages.
Whole grain cereals provide essential nutrients like carbohydrates, protein, fats, vitamins, and minerals. At least four servings of whole grains should be consumed daily for optimal health.
Transcripts
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cookie grade 10
first quarter lesson two
learning outcome number one our topic is
prepare cereals and starch dishes
for pouring misen plus
sources of starch the parts of plants
that store most starch
are seeds roots and tubers thus the most
common sources of food starch
are cereal grains including corn
wheat rice grain sorghum and oats
roots are tubers which includes potatoes
sweet potato
arrowroot and tropical cassava plant
which is marketed as tapioca and
legumes
the common source of manufactured food
starch are
corn potato and tapioca
starches are named after its plant
sources
corn starch from corn rice starch from
rice and tapioca from cassava
classification of starch first is the
native or natural starch
it refers to the starches as originally
derived from its plant source
second modified starches
these are starches that had been altered
physically or chemically
to modify one or more of its key
chemicals
or physical property
the next classification is the purified
starch
purified starch may be separated from
grains and tubers
by the process called wet milling
this procedure employs various
techniques of grinding
screening centrifuging to separate the
starch from fiber
oil and protein
starch composition in its structure
the starch molecule starch is a
polysaccharide made up
of hundreds or even thousands of glucose
molecules
joined together the molecules of starch
are
two general types called fractions
the amilus and the amylopectin
the amylus is a long chain like molecule
sometimes called linear fraction
and is produced by linking together five
hundred to two thousand glucose
molecules
the amylose production of starch
contributes gelling characteristic to
cook
and cold starch mixture a gel is a rigid
to a certain degree and holds a shape
when molded
amilopectin has a highly branched bush
type
of structure it is very different from
the long string-like molecules
of amylus in both amylose and
amylopectin however
the basic building unit is glucose
cohesion or thickening properties are
contributed by amylopectin
when a starch mixture is cooked in the
presence of
water but this fraction does not produce
a gel
most natural starches are mixtures of
the two fractions
corn wheat rice potato and tapioca
starches
contains 24 to 16 amylus
with the remainder being amylopectin
the root starches of tapioca and potato
are lower in amilu's content than the
cereal starches of corn wheat and rice
the starch granule in the storage areas
of plants
notably the seeds and roots molecules of
starch are deposited in tiny
organized units called granules
amylus and amylopectin molecules are
placed together
in tightly packed stratified layers form
around a central spot in the granule
called
the helum
the starch granule the starch molecules
are systematically structured in the
granule to form crystalline-like
patterns
if the starch granules in water
suspension are observed
microscopically under polarized light
the highly oriented structure it causes
the light to be rotated
so that a multi-cross pattern on each
granule is observed
this phenomenon is called birefringence
the pattern disappears when the starch
mixture is heated and the structure
disrupted
the sizes and shapes of granules deeper
among starches
from various sources but all starch
granules are microscopic
in size
is
properties and reactions first is the
gelatination
the sum of changes that occur in the
first stages of heating starch granules
in a moist environment which includes
swelling of granules
as water is absorbed and disruption of
the organized granule structure
second is the viscosity the resistance
to flow
it increase in thickness or consistency
when the newly gelatinized starch is
stirred
more swollen granules break and more
starch molecules
spill causing increase of viscosity or
thickness
the type of sugar influences the
temperature and rate of gelatination
the effect of sugar is attributed to
competition for water
it was observed that sugar actually
interacts with the amorphous areas of
the starch granules
different sweeteners added to starch gel
preparation
honey molasses or granulated sugar
retrogradation retrogradation is the
process in which starch molecules
particularly the amilus braction
reassociate or band together
in ordered structure after disruption by
gelatination
ultimately a crystalline order appears
next is the cyanisis
oozing of liquid from gel when cut and
allowed to stand
the oozing of liquid from a redwood gel
sometimes called
weeping this reactions occurs in all
kinds of gels
which includes pudding jellies custards
gelatine and agar
next is the dextrinization it is the
process of forming dextrin
dex strains are partially hydrolyzed
starches
that are prepared by dry roasting
in home kitchens dextrinization is
achieved by toasting flour purple bronze
rice flour per caricata sauce and bread
slices per breakfast
and finally the hydrolysis hydrolysis
starches
undergrow hydrolysis during cooking
or processing and during storage of food
or a chemical reaction in which a
molecular linkage is broken
and a molecule of water is utilized
prolonged heating of starches with acid
will promote hydrolysis
this can happen when cooking an acidic
food
such as pineapple pie resulting in a
reduced viscosity
or firmness of the pie filling
functional properties of starches
starch plays various roles in food it is
a typical multitasker
it acts as thickeners in gravies
sauces and pudding it absorbs water and
become a gel and cook
it also acts as a colloidal stabilizers
moisture retainer gel farming agents
binder package flavor carriers
it has the ability to drop oils and pots
which absorb flavoring substance
more efficiently
starches are can be added in the
processed meats like
luncheon meats hot dogs and sausages
it is also can be used as a filler
binder
moisture retainer and fat substitutes
the quality characteristics of the
starch itself
depends upon which roller function it
was used
cereal on the other hand is any grain
that is used for food
grains especially whole grain are not
just empty calories
these are very valuable and can
contribute a great deal to our
health you should include at least four
servings from this food group
each day
cereal processed food a whole grain
cereal is a grain product that has
retained the specific nutrients of the
whole
and processed grains and contains
natural proportion of bran
germ and in the sperm enriched cereals
are excellent sources of thyamine
niacin riboflavin and iron
a restored cereal is one made from
either the entire grain
or portions of one or more grains to
which there have been added sufficient
amounts of thiamine
niacin and iron to attain the accepted
whole grain levels of these three
nutrients
found in the original green from which
the cereal is prepared
cereals provide the body with
carbohydrates protein
fats vitamins minerals water and
cellulose
a time to remember
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this is smiling thank you for watching
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