What is plant starch commonly known as?

December 1, 2025 •

3 min read

According to the National Institutes of Health, starch makes up almost 90% of the daily calorie intake from staple foods worldwide, yet most people are unfamiliar with its scientific name. The compound most commonly referred to as plant starch is scientifically known as amylum.

Quick Summary

The scientific name for plant starch is amylum, derived from the Latin term. This polymeric carbohydrate serves as the primary energy storage for most green plants and is a major component of staple foods like corn, rice, and potatoes. Amylum consists of two molecules, amylose and amylopectin, which determine its properties.

Key Points

Amylum is the Scientific Name: The common term "plant starch" is scientifically known as amylum, derived from the Latin word.
Starch is Plant Energy Storage: Plants store excess glucose from photosynthesis as starch in granules within their cells, using it for energy later.
Two Molecular Forms: Starch consists of two polymers, amylose (linear) and amylopectin (branched), which affect its properties.
Common Examples: Everyday starches include cornstarch, potato starch, and tapioca, each with different culinary uses.
Human Energy Source: As a primary carbohydrate in the human diet, starch is broken down by enzymes into glucose to provide energy for the body.
Industrial and Food Applications: Beyond cooking, starch is used as a thickening agent, binder, and filler in various food products and industrial applications like paper manufacturing.

The Scientific and Commercial Names of Starch

Starch, or amylum, is a polymeric carbohydrate produced by most green plants as an energy reserve. It is composed of numerous glucose units joined by glycosidic bonds. This energy reserve is stored in specialized structures within plant cells, ready to be broken down into glucose when the plant requires it. While the scientific term 'amylum' is not widely used in everyday language, the commercial products derived from various plants are staples in kitchens and industries around the world.

The most common commercial starches, known by specific plant-based names, include:

Cornstarch (or Cornflour): Extracted from maize, it is a versatile thickener for gravies, sauces, and soups.
Potato Starch: A fine, gluten-free powder from crushed potatoes, used for thickening and baking.
Tapioca Starch: Derived from the cassava root, used for thickening sauces and creating translucent gels.
Wheat Starch: Used in baking and as a thickening agent, though less common in some regions due to gluten content.
Rice Starch: A finely textured powder used in some cuisines and food products.

The Two Molecular Forms of Amylum

At the molecular level, plant starch is not a single uniform compound but rather a mixture of two different glucose polymers: amylose and amylopectin. The ratio of these two components determines the texture, gelling properties, and overall behavior of the starch.

Amylose: This is a linear, unbranched chain of glucose units. Because of its helical, compact structure, it is less soluble in water and slower to digest. Starches with a higher proportion of amylose are associated with stronger gelling properties. For example, high-amylose cornstarch is prized for its gel strength.

Amylopectin: This is a highly branched polymer of glucose molecules. Its branched structure allows for more access points for enzymes, enabling quicker digestion. Starches with a high amylopectin content, known as waxy starches, undergo less retrogradation and produce a more stable paste. These are found in waxy maize and glutinous rice.

Comparison of Starch Types


Feature	Amylose	Amylopectin
Structure	Linear and helical chains	Highly branched chains
Solubility in Water	Less soluble	More soluble
Digestion Speed	Slower to digest	Rapidly digested
Gelling Properties	Forms strong gels	Forms softer pastes, resists gelling
Example Sources	Amylomaize corn	Waxy maize, glutinous rice
Crystalline Nature	Amorphous	Crystalline

The Function of Starch in Plants and Humans

For plants, starch serves as the primary way to store energy. During photosynthesis, plants produce excess glucose, which they convert into starch granules and store in organs like seeds, tubers, and roots. This stored energy is crucial for the plant's survival and growth, especially during periods when photosynthesis is not possible, such as at night or during the winter. The storage of glucose as starch is also vital for osmotic regulation, as starch is insoluble and does not disrupt the cell's water balance.

For humans, starch from plants is a critical source of dietary energy. Upon consumption, enzymes called amylases in our saliva and pancreas break down starch into its constituent glucose units, which are then absorbed into the bloodstream. This glucose fuels our cells, providing the energy needed for all bodily functions. Foods rich in starch are therefore considered essential parts of a healthy diet, supplying both energy and other nutrients.

Conclusion

In summary, while the scientific community refers to plant starch as amylum, most people recognize it by the names of the specific crops from which it is derived, such as cornstarch or potato starch. Its fundamental role as a stored energy source for plants translates directly into a crucial energy source for human nutrition. The dual molecular composition of amylose and amylopectin gives different starches their unique properties, which are leveraged in both the food and non-food industries. This complex carbohydrate, in all its various forms, is a silent but powerful ingredient shaping everything from our dinner plates to industrial products. The importance of starch in both plant physiology and human diets solidifies its place as a cornerstone of life on Earth.

An excellent resource for exploring the scientific and industrial uses of starch can be found on the ScienceDirect website, providing an overview of its structure and functionality.

Frequently Asked Questions

The primary function of starch in plants is to serve as a long-term energy reserve, storing excess glucose produced during photosynthesis. This stored energy can be accessed when the plant needs it, such as during the night or periods of low light.

Amylose and amylopectin are the two polysaccharide molecules that make up plant starch. Amylose is a linear chain of glucose, while amylopectin is a highly branched chain. Their ratio determines the texture and properties of a particular starch.

The human body digests plant starch with the help of enzymes called amylases, found in saliva and the pancreas. These enzymes break down the starch into smaller glucose units, which are then absorbed into the bloodstream to provide energy.

Cornstarch is widely used as a thickening agent because when heated in liquid, its starch molecules unravel and form a mesh-like structure, a process known as gelatinization. This traps water and causes the liquid to thicken.

Yes, in many Commonwealth countries like the UK, 'cornflour' is the term for what Americans call 'cornstarch'. In the US, cornflour refers to very finely milled cornmeal.

Yes, starch can be chemically, physically, or enzymatically modified to alter its properties for specific industrial applications. These modifications can improve its stability, viscosity, and functionality for use in foods, paper, and adhesives.

No, storing glucose as insoluble starch helps plants maintain cellular water balance. Because starch does not affect the osmotic potential of the cell, plants can store large amounts of energy compactly without disrupting the cell's internal environment.