Starch in dairy products presentation. Presentation for the research work "mysterious starch and its significance." Choose the correct statements

Starch

Variety of substances

The world

Educational and training complex "School of Russia"

Goal of the work

Get to know

properties of starch.

Find out how it is obtained and where it is used.

Add the starch sample to the substance collection.

• Chemical starch formula
• A model of this molecule can be made

Properties of starch

Free-flowing white powder, tasteless and odorless, creaks when rubbed.

Starch does not dissolve at all in cold water, and after a while it “sits” to the bottom and the solution becomes almost transparent;

In warm water it forms a milky liquid, and after a while it “sits” to the bottom and the solution becomes transparent.

Starch in hot water only swells, but does not dissolve. The result was a colorless viscous mass, sticky to the touch. From the literature I learned that this solution is called a paste.

Being in nature

In corn and wheat 70 percent

Rice contains 80 percent.

In potato tubers - 25 percent.

• Starch is most often obtained from potatoes in factories. To do this, the potatoes are crushed, washed with water and pumped into large vessels where settling occurs. The resulting starch is washed again with water, settled and dried in a stream of warm air.

Food industry

Paper industry

Application

Medicine

Starch is the basis for the production of glue

Using starch at home

Starch shirts - soak in starch solution

Preparing jelly

Starch paste,

which glues paper so well

conclusions

• starch is a white, tasteless substance;
• insoluble in cold water, swells in hot water, forming a paste;
• creaks when friction occurs;
• has physical and chemical properties;
• occurs in nature;
• it is obtained in factories mainly from potatoes
• a person needs to eat and maintain health;
• used in medicine,

cosmetics and other

industry

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Classification and characteristics of the assortmentDepending on the source of receipt
· potato
corn
· wheat
· tapioca
· rice

Depending on the technology features

unmodified
modified:
hydrolyzed
swelling
oxidized
gelling
phosphate.

By quality

Potato starch is divided into varieties:
Extra
Higher
First
Second.
Wheat starch comes in the following varieties:
Extra
Higher
First
Corn and rice:
First
Second

Potato starch forms a viscous transparent
paste. For its production, universal varieties are used
potatoes, characterized by high yield and large
starch content.
Corn starch produces a low-viscosity paste,
opaque, milky white. For its production
Starchy corn varieties are most suitable.
Wheat starch produces a paste of reduced viscosity,
but more transparent compared to corn.
Tapioca starch forms a transparent viscous
paste. Tapioca starch is an analogue of potato and
produced in Asia from the root of the legume cassava (cassava).
Rice starch forms an opaque paste.

Assortment characteristics of individual species

Many people think that "modified"
means a genetically modified product.
However, in this case this only means that
starch has been chemically treated
for example, oxidation.
This modification allows you to change the properties
starch so that it performs its functions
thickener, stabilizer or improver
quality of flour in various products.
The nutritional value of starch is not
is changing.

Assortment characteristics of individual species

Hydrolyzed starch is produced by partial
hydrolysis of starch.
Swelling - during heat treatment of a thin layer
concentrated starch paste (has the ability
dissolve in water)
Oxidized - as a result of the interaction of starch with
oxidizing agents (H2O2, KMnO4).
Phosphate - through the interaction of starch with phosphorus
acid or its salts.
Gelling starch is obtained by oxidizing potato
starch with a weak solution of potassium permanganate in the presence
hydrochloric acid, then thoroughly washed and dried.
Characterized by increased gelatinizing ability. IN
it has become widespread in the confectionery industry
as a student educator.

Consumer properties

Starch makes up the main share
carbohydrates consumed by humans. He's easy
digested and absorbed by the body, has
high nutritional value.
In the food industry, starch is found
wide application: in the production of biscuits,
cakes, sweets, oriental sweets,
pasta, some types of sausages.
Starch is used for cooking
jelly, sauces and as a molding agent
material for casting fondant, milk and
liqueur varieties of sweets.

Consumer properties

Chemical composition and energy value
Components
Water, g
Proteins, g
Fats, g
Carbohydrates
digestible, g
Mineral
substances, g
Energy
value, kcal
(kJ)
Potato
starch
Corn
starch
20
0,1
Footprints
13
1
0,6
79,6
85,2
0,1
0,07
299 (1251)
329 (1377)

Factors shaping quality

Potato starch technology
Washed
Grind
Wash with water (forms
starch milk) pulp
remains on the sieve


Raw starch is dried
Sift and pack.

Technology of corn (rice,
wheat) starch
Grains are soaked in acidified water
Crushed into large pieces
The embryo is separated
Grind to make porridge
Wash with water
Starch milk is cleared of impurities
Precipitate starch by settling
Raw starch is dried
Sift and pack.

Quality requirements

The color should be white, for higher grades of potato starch with
characteristic crystalline shade (of chandeliers) due to
reflectivity of large starch grains, for the rest
varieties white or white with a grayish tint. Corn and wheat
Starch is characterized by a natural slight yellowness.
Impurities of other types of starch and heavy metal salts are not
are allowed. When sifting 100 g of potato starch there should not be
stay sand.
Benign starch has no taste and does not allow crunch
when chewing.
Starch has a slight odor, musty and moldy odors do not
are allowed.
Starch must meet the requirements for the number of dark specks
per 1 dm2 of surface, mass fraction of moisture, ash content,
acidity, mass fraction of protein and sulfur dioxide.
Thus, the mass fraction of moisture of corn starch should be no more than 13,
potato no more than 20%.

Factors that maintain quality

Packaging and labeling
o Starch is packaged in double fabric or
paper bags: potato - net weight
no more than 50 kg, corn - 25, 50, 60 kg (for
industrial processing 70 kg).
o Starch can be packaged in small containers from
paper, polyethylene, film weighing from 250 to
1000 g
o Markings are applied indicating
warning sign “Afraid of dampness.”

Storage

Store packaged starch in dry, clean and
well ventilated, free of foreign odors and
warehouses uninfested with pests.
It is not allowed to store starch together with products
having a specific odor.
An important condition for proper storage of starch is
maintaining relative air humidity no higher
75%.
The optimal storage temperature is 10 °C.
Guaranteed shelf life of potato and
corn starch 2 years from the date of production,
wheat - 1 year.

Starch defects

Starch defects occur mainly when
violation of technology or storage conditions.
These include:
Presence of mechanical and foreign impurities
Smell and taste of fermentation products
Crunch when chewing
Grey colour
Increased mass fraction of moisture
Development of microorganisms.
Starch with such defects is used
for technical purposes.

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The presentation on the topic "Starch" can be downloaded absolutely free on our website. Project subject: Chemistry. Colorful slides and illustrations will help you engage your classmates or audience. To view the content, use the player, or if you want to download the report, click on the corresponding text under the player. The presentation contains 13 slide(s).

Presentation slides

Slide 1

Slide 2

Starch consists of 2 polysaccharides - amylose and amylopectin, formed by glucose residues. It has been experimentally proven that the chemical formula of starch is (C6H10O5)n.

It has been established that starch consists not only of linear molecules, but also of molecules with a branched structure. This explains the granular structure of starch. Accumulates in the form of grains, mainly in the cells of seeds, bulbs, tubers, as well as in leaves and stems. Starch is a white powder, insoluble in cold water. In hot water it swells and forms a paste.

The structure of starch.

Slide 3

Physical Properties

Tasteless, amorphous white powder, insoluble in cold water; in hot water it swells (dissolves), forming a colloidal solution - a paste. Under a microscope it can be seen that it is a granular powder; When you squeeze starch powder in your hand, it produces a characteristic “crunch” caused by the friction of the particles.

Slide 4

Chemical properties

It swells in hot water, in water and with the addition of acid (H2SO4, diluted, etc.) as a catalyst, it gradually hydrolyzes with a decrease in molecular weight, down to glucose. Forms a colloidal solution (starch paste); with iodine solution gives a blue color. Starch molecules are heterogeneous in size. Starch is a mixture of linear and branched macromolecules. Under the action of enzymes or heating with acids, it undergoes hydrolysis. Equation: (C6H10O5)n + nH2O-H2SO4→ nC6H12O6. Qualitative reactions: Starch, unlike glucose, does not give a silver mirror reaction. Like sucrose, it does not reduce copper(II) hydroxide. Interaction with iodine (blue color).

Slide 5

Nutritional value

In the gastrointestinal tract of humans and animals, starch is hydrolyzed and converted into glucose, which is absorbed by the body. Starch, as a food additive, is used to thicken many foods, prepare jelly, dressings and sauces.

Slide 6

Biological properties

Starch, being one of the products of photosynthesis, is widespread in nature. For plants, it is a supply of nutrients and is found mainly in fruits, seeds and tubers. The grains of cereal plants are the richest in starch: rice (up to 86%), wheat (up to 75%), corn (up to 72%), and potato tubers (up to 24%).

Slide 7

For the human body, starch, along with sucrose, serves as the main supplier of carbohydrates - one of the most important components of food. Under the action of enzymes, starch is hydrolyzed to glucose, which is oxidized in cells to carbon dioxide and water, releasing the energy necessary for the functioning of a living organism.

Slide 8

Starch modification

In industry, the conversion of starch into glucose (saccharification process) occurs by boiling it for several hours with dilute sulfuric acid (the catalytic effect of sulfuric acid on the saccharification of starch was discovered in 1811 by K. S. Kirchhoff). To remove sulfuric acid from the resulting solution, chalk is added to it, producing insoluble calcium sulfate from sulfuric acid. The latter is filtered off and the substance is evaporated. The result is a thick sweet mass - starch syrup, which contains, in addition to glucose, a significant amount of other starch hydrolysis products. Molasses is used for the preparation of confectionery products and for a variety of technical purposes. If you need to get pure glucose, then boiling the starch takes longer than it is more completely converted into glucose. The solution obtained after neutralization and filtration is concentrated until glucose crystals begin to fall out of it. Also, currently, starch hydrolysis is carried out enzymatically, using alpha-amylase to produce dextrins of various lengths, and glucoamylase for their further hydrolysis to produce glucose.

Slide 9

When dry starch is heated to 200-250°C, its partial decomposition occurs and a mixture of polysaccharides less complex than starch (dextrin and others) is obtained. The physical change produces starch with a high moisture-holding capacity, which in turn gives the final product the desired consistency. Modified starch has nothing to do with genetically modified organisms, since it is not changed at the genetic level.

Modified starch

Slide 10

Application of starch.

Starch is the main part of the most important food products: flour (75 - 80%), potatoes (25%), sago, etc. Energy value is about 16.8 kJ/g. It is a valuable nutritious product. To facilitate its absorption, starch-containing foods are exposed to high temperatures, that is, potatoes are boiled, bread is baked. Under these conditions, partial hydrolysis of starch occurs and dextrins, soluble in water, are formed. Dextrins in the digestive tract undergo further hydrolysis to glucose, which is absorbed by the body. Excess glucose is converted into glycogen (animal starch). The composition of glycogen is the same as that of starch - (C6H10O5)n, but its molecules are more branched. The liver contains especially a lot of glycogen (up to 10%). In the body, glycogen is a reserve substance that is converted into glucose as it is consumed in cells. In industry, starch is converted into molasses and glucose by hydrolysis. To do this, it is heated with dilute sulfuric acid, the excess of which is then neutralized with chalk.

Slide 11

The resulting precipitate of calcium sulfate is filtered off, the solution is evaporated and glucose is isolated. If starch hydrolysis is not completed, a mixture of dextrins and glucose is formed - molasses, which is used in the confectionery industry. Dextrins obtained from starch are used as glue to thicken paints when applying designs to fabric. Starch is used for starching linen. Under a hot iron, starch is partially hydrolyzed and converted into dextrins. The latter form a dense film on the fabric, which adds shine to the fabric and protects it from soiling. Starch and its derivatives are also used in the production of paper, textiles, foundries and other industries, as well as in the pharmaceutical industry.

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Starch is a natural polymer (C6H10O5)n where n is from several hundred to several thousand In potatoes - 20% In rice - 80% Wheat and corn - 70% Preparation Starch is most often obtained from potatoes. To do this, the potatoes are crushed, washed with water and pumped into large vessels where settling occurs. The resulting starch is washed again with water, settled and dried in a stream of warm air. Physical properties Occurs in the form of white grains. Starch grains are insoluble in cold water; In hot water, the membrane of the grains bursts and the starch forms a colloidal solution (gel). Does not have a sweet taste. Chemical properties Qualitative reaction to starch. Iodine forms an intensely blue complex compound with starch Experiment “Qualitative reaction” Hydrolysis Reaction equation: (C6H10O5)n + n H2O → n C6H12O6 Stepwise hydrolysis Starch dextrins maltose glucose Destruction upon heating When starch is heated, macromolecules are destroyed with the formation of compounds with a lower molecular weight - dextrins. Due to partial dehydration, dextrins acquire a yellow and golden brown color. This process occurs when baking flour confectionery products, since starch makes up the main part of wheat flour. Experience “Acid hydrolysis of starch” Application in the paper industry Corn starch is used for roll sizing and surface sizing in the paper industry. This increases paper strength, lays down surface lint and increases document stiffness and rattle. Use in confectionery and bakery production Corn starch is widely used in the food industry as a thickener for sauces, puddings and pie fillings. In bakeries, it helps soften wheat flour and provides good texture. Textile Applications Corn starch can be easily converted into a smooth paste within an hour by pressure cooking. This makes its use in the textile industry widely popular. Its viscosity ensures uniform flow and penetration into the interstices of the yam, which ensures a good weave of the thread. Application in construction For the production of building mixtures, thickeners and binders based on corn starch are used. Starch-based additives are being developed for the construction industry. They are used to impart specific properties to cement mortars, plaster mortars, gypsum products, finishing mixtures, etc. Applications in Pharmaceutical Industry Corn starch is most suitable as a tablet compression vehicle in the pharmaceutical industry.