Starch

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Starch
Starch cornstarch sample.jpg
Cornstarch sample
Names
IUPAC name
5-(5-(3,4-dihydroxy-6-(hydroxymethyl)-5-methoxyoxan-2-yl)oxy-6-((3,4-dihydroxy-6-(hydroxymethyl)-5-methoxyoxan-2-yl)oxymethyl)-3,4-dihydroxyoxan-2-yl)oxy-6-(hydroxymethyl)-2-methyloxane-3,4-diol[1]
Other names
Amylum
Clearjel
Keestar
Maizena
Properties
(C6H10O5)n
(n=300-3,000) (amylose)
(n=2,000-200,000) (amylopectine)
Molar mass 168.15·n
Appearance White powder
Odor Odorless
Density 1.5 g/cm3
Melting point Decomposes
Boiling point Decomposes
Insoluble
Vapor pressure 0 mmHg
Hazards
Safety data sheet ICSC: 1553
Related compounds
Related compounds
Dextrin
Cellulose
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Starch or amylum is a carbohydrate, an organic compound consisting of a large number of glucose units joined by glycosidic bonds. Pure starch consists of two types of molecules: the linear and helical amylose and the branched amylopectin. Depending on the plant, starch generally contains 20 to 25% amylose and 75 to 80% amylopectin by weight.

Cornstarch is generally preferred in most reactions, though for some reactions potato starch is required.

Properties

Chemical

Starch is used in iodine clock reactions.

Physical

Starch is a white solid, odorless and tasteless, insoluble in cold water and other solvents. Hot water will cause starch to dissolve, a process known as starch gelatinization, which is irreversible. Starch decomposes when heated to other compounds, such as dextrin or chars at higher temperatures. Starch has an average density of 1.5 g/cm3.

Availability

Starch powder is sold by most food stores and supermarkets.

Preparation

Starch can be extracted from a variety of starch containing plants such as corn, potato, wheat, etc.

Projects

  • Make food
  • Make dextrin
  • Iodine clock reaction
  • Dust explosion

Handling

Safety

Starch has very low toxicity and is perfectly edible. However, it may stain clothing and is difficult to properly remove.

Finely dispersed particles in air can form extremely dangerous explosive mixtures, known as dust explosions.

Storage

Starch should be stored in closed containers or zip bags, away from moisture and pests.

Disposal

Starch doesn't require special disposal. Discard it as you wish.

References

  1. https://pubchem.ncbi.nlm.nih.gov/compound/24836924#section=Names-and-Identifiers

Relevant Sciencemadness threads