Introduction to Starch and Cereals

Summary

Miss 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

00:00

🍚 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.

05:03

🔬 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.

Keywords

💡Starch

Starch is a complex carbohydrate that serves as a primary energy source for the body. It is a major component of many staple foods and is found in plants such as seeds, tubers, and roots. In the video, starch is introduced as a key ingredient in various types of cereal dishes, and the lesson aims to help viewers understand its role in food preparation and its nutritional value.

💡Cereals

Cereals refer to a group of grasses cultivated for their edible grains or seeds, which are used as staple foods. The video mentions rice, wheat, and corn as the most cultivated cereals globally. Cereals are highlighted as a significant source of starch, emphasizing their importance in human nutrition and agriculture.

💡Native Starch

Native or natural starch is the form of starch as it is originally found in plants without any alteration. The video script uses the example of eating sweet potatoes or corn to illustrate the consumption of native starch, emphasizing the purity and natural state of these ingredients.

💡Modified Starch

Modified starch refers to starch that has undergone a physical or chemical change from its original state. An example given in the script is cooked rice, where the starch has been altered through the cooking process. This modification can affect the texture, appearance, and other properties of the starch.

💡Purified Starch

Purified starch is obtained through processes like grinding and screening to separate it from other components like fiber, oil, and protein. The video explains that this type of starch is derived from its source in a highly refined form, which can be used in various food preparations for specific culinary purposes.

💡Amylose

Amylose is a type of starch molecule characterized by its linear structure, formed by the linkage of hundreds to thousands of glucose molecules. The video describes its role in the gelling properties of starch when cooked and cooled, which is crucial for the texture of certain dishes.

💡Amylopectin

Amylopectin is another type of starch molecule, known for its highly branched structure. It contributes to the thickening properties of starch when cooked with water, as mentioned in the video. This property is essential for the preparation of various cereal dishes and sauces.

💡Gelatinization

Gelatinization is the process where starch granules absorb water and swell when heated, leading to a change in texture. The video script explains that this process is a key reaction in cooking starch-based foods, as it affects the final consistency and mouthfeel.

💡Viscosity

Viscosity in the context of the video refers to the resistance to flow in a liquid, which increases as starch is cooked and its granules swell. The script uses the example of a butter or pancake mixture to illustrate how viscosity changes the thickness and flow characteristics of a mixture.

💡Retrogradation

Retrogradation is the process where starch loses moisture after gelatinization, leading to a firmer texture. The video gives the example of bread, where retrogradation causes the bread to become dry and less desirable over time, affecting its taste and texture.

💡Dextrinization

Dextrinization is the process where starch is toasted or pan-fried without fat or liquid, resulting in a brown color. The video uses the preparation of brown sauce or gravy as an example, where dextrinization contributes to the development of flavor and color in the dish.

💡Hydrolysis

Hydrolysis in the context of the video is the process where starch is broken down by prolonged heating with acid. This is illustrated with the example of cooking acidic foods like pineapple pie, where hydrolysis can affect the firmness and texture of the filling.

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