Introduction to Starch and Cereals
Summary
TLDRMiss Gina Rasilia introduces viewers to the world of starch and cereals in a lively cookery class. She outlines the objectives, including identifying starch sources, understanding composition, and recognizing nutritive value. The lesson distinguishes between native, modified, and purified starches, and delves into the molecular structure of amylose and amylopectin. Key properties and reactions like gelatinization, viscosity, retrogradation, syneresis, dextrinization, and hydrolysis are explained, offering a comprehensive insight into the science behind starch in cooking.
Takeaways
- 🍚 Identifying the ingredients in starch and cereal dishes is crucial for understanding their preparation.
- 🌾 Cereals are starchy pods or grains, with rice, wheat, and corn being the most cultivated worldwide.
- 🌱 Starch is classified into native (natural), modified, and purified, based on the extent of processing from its plant source.
- 🔬 Starch molecules consist of two types: amylose, which forms gels when cooked and cooled, and amylopectin, which contributes to thickening.
- 🍲 Gelatinization is the process where starch absorbs water and is heated, leading to a change in structure and texture.
- 📈 Viscosity in starch is influenced by the amylopectin content, causing an increase in thickness or consistency when stirred.
- 🍞 Retrogradation is the loss of water from starch after gelatinization, which can make bread dry and tough.
- 🍋 Syneresis is the shrinkage of a gel and loss of moisture, often observed in protein-rich foods like lemon meringue pie.
- 🍯 Dextrinization occurs when starch is toasted or pan-fried without fat or liquid, turning it brown and contributing to the flavor of sauces and gravies.
- 🍍 Hydrolysis is the breakdown of starch promoted by prolonged heating with acid, which can affect the texture of acidic foods like pineapple pie.
Q & A
What are the main objectives of the lesson on starch and cereals?
-The main objectives are to identify the sources and kinds of starches, understand their composition and structure, learn about their properties and reactions, and know their nutritive value.
What are the three most cultivated cereals in the world?
-The three most cultivated cereals in the world are rice, wheat, and corn.
What are the three kinds of starch discussed in the script?
-The three kinds of starch discussed are native or natural starch, modified starch, and purified starch.
What is the difference between native and modified starch?
-Native or natural starch is starch as originally derived from its plant source without any alteration, while modified starch has undergone physical or chemical changes from its natural source, such as cooking rice.
How is purified starch obtained?
-Purified starch is obtained through various techniques of grinding and screening to separate starch from fiber, oil, and protein.
What are the two types of starch molecules, and what are their functions in food?
-The two types of starch molecules are amylose and amylopectin. Amylose is responsible for the gelling characteristics of starch when cooked and cooled, while amylopectin contributes to the cohesion or thickening properties when a starch mixture is cooked in the presence of water.
What is the process called when starch absorbs water and is heated?
-The process is called gelatinization.
What is viscosity in the context of starch, and how does it relate to amylopectin content?
-Viscosity is the resistance to flow, which increases in thickness or consistency when newly gelatinized starch is stirred. This reaction is the result of its amylopectin content.
What is retrogradation and how does it affect bread?
-Retrogradation is the loss of water or moisture content after gelatinization. In bread, retrogradation expels water from the bread structure, causing the bread to lose moisture and become dry, which can affect its taste.
What is cineresis and how does it affect gels in food?
-Cineresis is the shrinkage of a gel and subsequent loss of moisture or liquid. Gels affected by cineresis more quickly if exposed to protein, such as in lemon meringue pie or scrambled eggs.
Describe the process of dextranization as it relates to preparing brown sauce or gravy.
-Dextrinization is the process where flour, an example of starch, is toasted or pan-fried first without any fat or liquid content until it becomes brown in color. This process is used in preparing brown sauce or gravy.
How is hydrolysis related to cooking acidic foods like pineapple pie?
-Hydrolysis is promoted by prolonged heating of starch with acid, which can happen when cooking acidic foods such as pineapple pie, resulting in the firmness of the pie filling.
Outlines
🍚 Introduction to Starches and Cereals
Miss Gina Rasilia introduces the topic of starch and cereals in the context of technology and livelihood education. The lesson aims to identify the ingredients used in various starch and cereal dishes. The objectives include understanding the sources and types of starches, their composition and structure, properties and reactions, and their nutritive value. Cereals are defined as starchy grains, with rice, wheat, and corn being the most cultivated. The classification of starch is discussed, including native starch (unaltered from its plant source), modified starch (altered physically or chemically), and purified starch (separated from fiber, oil, and protein). The structure and composition of starch, including amylose and amylopectin, are explained, along with their functions in food.
🔬 Properties and Reactions of Starches
This segment delves into the properties and reactions of starches. Gelatinization is described as the process where starch absorbs water and is heated, leading to an increase in viscosity or thickness due to the amylopectin content. Retrogradation is the loss of water after gelatinization, which can cause bread to dry out and become less desirable. Cineresis is the shrinkage of a gel and loss of moisture, exemplified by lemon meringue and scrambled eggs when exposed to protein. Dextrinization is the browning of starch when heated without fat or liquid, as seen in preparing brown sauces or gravies. Hydrolysis is the breakdown of starch promoted by prolonged heating with acid, which can affect the firmness of acidic food fillings like pineapple pie.
Mindmap
Keywords
💡Starch
💡Cereals
💡Native Starch
💡Modified Starch
💡Purified Starch
💡Amylose
💡Amylopectin
💡Gelatinization
💡Viscosity
💡Retrogradation
💡Dextrinization
💡Hydrolysis
Highlights
Introduction to the importance of identifying ingredients in starch and cereal dishes.
Objectives of the lesson: identifying sources and kinds of starches, their composition and structure, properties and reactions, and nutritive value.
Definition of cereals as starchy pods or grains, with rice, wheat, and corn being the most cultivated.
Classification of starch into native, modified, and purified starches.
Explanation of native starch as unaltered starch from its plant source.
Description of modified starch as altered starch due to physical or chemical changes, such as cooking rice.
Process of obtaining purified starch through grinding and screening to separate it from fiber, oil, and protein.
Structure and composition of starch molecules, including amylose and amylopectin, and their roles in food.
Function of amylose in providing gelling characteristics when starch is cooked and cooled.
Role of amylopectin in contributing to the thickening properties of starch when cooked.
Property of gelatinization, which occurs when starch absorbs water and is heated.
Explanation of viscosity as the resistance to flow, influenced by the amylopectin content in starch.
Process of retrogradation, where starch loses water or moisture content after gelatinization, affecting the texture of bread.
Cineresis, the shrinkage of a gel and loss of moisture, particularly in lemon meringue and scrambled eggs.
Dextrinization, the process of browning starch when toasted or pan-fried without fat or liquid, as in preparing brown sauce or gravy.
Hydrolysis, the breakdown of starch promoted by prolonged heating with acid, affecting the firmness of acidic food fillings like pineapple pie.
Conclusion of the lesson, emphasizing continuous learning in technology and livelihood education.
Transcripts
hello
good day i am miss gina rasilia your
technology and livelihood education
teacher in grades it ta-da let's explore
life-long lessons in today's episode
are you ready
so welcome to our cookery class
our today's topic has something to do
with the introduction of starch and
and with that
let me start by stating the most
essential learning competency of our
lesson and that is to identify the
ingredients in the preparation of
various types of starch and cereal
dishes
you have to stay focused because we are
going to talk about lots of things about
starch and cereals these are our
objectives first you are going to
identify the sources and kinds of
starches
followed by its composition and
structure you also have to know the
properties and reactions of starch and
lastly
know its nutritive value
let us now give the definition of
cereals when we say cereals
they are usually starchy pods or grains
cereal grains are the most important
group of food crops in the world
rice wheat and corn are the most
cultivated cereals in the world
now let's move on to the classification
of starch
the parts of plant that store most of
the starches are seeds roots and tubers
there are three kinds of starch
we are going to discuss them one by one
let's start with a native or natural
starch
this refers to the starches as
originally derived from its plant source
this means
there is no alteration or modification
that happened to the starch
it's like you just eat sweet potato or
corn or any fresh cereal or greens and
from that
you can get the natural starches
the second kind of starch is called
modified starches
this means
something has been changed from its
natural source for example
you cook rice
there is already physical or chemical
change that happen and that is
considered as modified starch
the last one is called
purified starch
this procedure employs various
techniques of grinding and screening
that is to separate starch from fiber
oil and protein
and to give you more information of the
starch and cereals
let us discuss its structure and
composition
there are two types of starch molecules
they are called amylose and amylopectin
amylose is a long-chain-like molecule
sometimes called the linear fraction
and
is produced by linking together
500 to 2 000 glucose molecules
what is its function to food
it is responsible to gelling
characteristics of starch when they are
cooked and cooled
and on the other hand
we also have amylopathy
amelopetine has highly branched
bushy type of structure
cohesion or thickening properties are
the contribution of amylopectin when a
starch mixture is cooked in the presence
of water
want to learn some more
okay let's find out the properties and
reactions of starch
the first one is called gelatinization
this means
this will take place when starch absorbs
water
and be heated
once the starch is combined with water
or any liquid ingredients then heated
the process is called gelatinization
next we have viscosity
or the resistance to flow
this means to increase in thickness or
consistency
when newly gelatinized starch is steered
more swollen granules break
and more starch molecules spills
causing increase in viscosity or
thickness this reaction is the result of
its amylopectin content
when starch in water has combined or was
combined
and can be steered it is viscosity
example of this is butter or pancake
mixture
though the mixture is thick
still it has the ability to flow
the third properties and reactions of
starch is called retrogen
this means
losing of water or moisture content
after gelatinization for example in
making bread retrogradation expels water
from the bread structure
water will then evaporate in a suitable
conditions to leave the bread structure
causing the bread to lose moisture
hence the bread will be more dry and
become undesirable in terms of taste
next we have cineresis
it is the shrinkage of a gel and
subsequent loss of moisture or liquid
gels affected by tenerises more quickly
if exposed to protein
an example of this is lemon meringue
plus starchy lemon meringue
filling reacts to scenarios is quickly
because it is exposed to protein
in the mirror
another example of cenarises is
scrambled egg
which if overcooked shrinks and produces
liquid
now let's have dextranization
best example of this is when we are
going to prepare brown sauce or gravy
where flour an example of starch were
toasted first or pan fry first without
any fat or liquid content
when it becomes brown in color the
process is called dextrinization
and lastly we have hydrolysis
this is promoted by prolonged heating of
starch with acid
this can be happened when cooking an
acidic food such as
pineapple pie
resulting to firmness of pie filling
and that is our lesson for today's
episode i hope you've learned a lot
always remember at tle we keep on going
beyond the traditional
bye bye
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