Carbohydrates - Dextrinisation and Gelatinisation

Summary

This video explains the different types of carbohydrates—monosaccharides, disaccharides, and polysaccharides—focusing on starch. It details the role of starch in food processing, highlighting the importance of the amylose and amylopectin ratio in determining texture and function. Starch’s ability to thicken liquids through gelatinization is discussed, along with factors like temperature and pH that affect its properties. The video also covers starch breakdown (dextrinization), which leads to browning and the formation of simpler sugars like maltose and glucose. Understanding these concepts is key to mastering the functional properties of carbohydrates in cooking.

Takeaways

• 😀 Starch is a polysaccharide found in grains like rice and vegetables like potatoes.
• 😀 Starch consists of two main substances: amylose and amylopectin.
• 😀 The ratio of amylose to amylopectin is crucial in determining the texture of foods.
• 😀 Most starches contain about 25% amylose, but some can contain up to 50%.
• 😀 Higher amylose content in starch leads to semi-solid and opaque gels in food.
• 😀 Gelatinization is the process by which starch thickens liquids when heat is applied.
• 😀 The physical properties of starch gels depend on the amylose-to-amylopectin ratio.
• 😀 Common starch-based thickeners include plain flour, corn flour, and arrowroot.
• 😀 Starch behavior is influenced by temperature, agitation, pH, and enzymes.
• 😀 Dextranization refers to the breakdown of starch into simpler sugars like maltose and glucose.
• 😀 Heat, acids, and certain enzymes trigger dextranization, altering starch's properties.

Q & A

What are the three types of carbohydrates?

The three types of carbohydrates are monosaccharides, disaccharides, and polysaccharides.

What is starch, and where is it commonly found?

Starch is a polysaccharide found in grains like rice and vegetables like potatoes.

What two substances make up starch?

Starch is made up of amylose and amylopectin.

Why is the ratio of amylose to amylopectin important?

The ratio of amylose to amylopectin is important because it affects the texture and consistency of food products, such as the opacity and firmness of gels.

How does starch thickening work?

Starch thickens liquids through a process called gelatinization, which occurs when heat is applied, causing the starch to absorb water and swell.

What factors affect the functional properties of carbohydrates?

Temperature, agitation, and pH levels all affect the functional properties of carbohydrates.

What is dextranization of starch?

Dextranization is the breakdown of starch into dextrans, and with continued breakdown, it forms maltose and eventually glucose.

How do heat, acids, and enzymes affect starch?

Heat, acids, and certain enzymes can break down starch, leading to changes in its structure and the formation of sugars like maltose and glucose.

What are some common ingredients used to thicken liquids?

Common ingredients used to thicken liquids include plain flour, corn flour, and arrowroot.

What determines the physical qualities of starch gels?

The ratio of amylose to amylopectin in starch determines the physical qualities of starch gels, such as their texture and clarity.