Amylose

Amylose is a polysaccharide, specifically a linear polymer of glucose molecules linked by α(1→4) glycosidic bonds. It is one of the two main components of starch, the other being amylopectin. amylose typically comprises around 20-30% of plant starch, though this percentage can vary depending on the plant species and its genetics. It's a crucial energy storage molecule in plants, providing a readily available source of glucose upon digestion. Amylose's linear structure allows it to coil into a helical shape, which plays a role in its water solubility and interaction with other molecules. The ratio of amylose to amylopectin significantly impacts the texture and digestibility of starch-containing foods. High-amylose starches tend to form gels upon cooling, while low-amylose starches have a waxy texture. The digestive enzymes responsible for breaking down amylose are called amylases.

Amylose meaning with examples

• In a study comparing the digestibility of different rice varieties, researchers found that the amylose content directly correlated with the rate of glucose release after consumption. High-amylose rice varieties displayed slower digestion due to the extended time needed to hydrolyze the linear amylose structure. This highlights the impact amylose has on a food's glycemic index.
• When making a bread recipe, the miller can select wheat flours that have varying amylose and amylopectin ratios. Flour with a higher amylose content contributes to a firmer crumb structure. This is because the amylose chains retrograde, forming a more solid gel network during the bread-baking process. Consequently, the resulting bread is more structurally sound.
• Specialized food processing methods, such as hydrothermal treatment, can alter the crystallinity and therefore the properties of amylose within starch granules. Changing the structural integrity of the amylose impacts its digestibility. The treatment might promote the formation of resistant starch. This means the amylose then becomes less susceptible to amylase enzymes, acting more like dietary fiber.
• The development of new crop varieties frequently involves manipulating the ratio of amylose to amylopectin through genetic engineering. This is done to create new starch varieties, which can be used in food and industrial applications with targeted properties. Creating high-amylose corn, for example, can change how food is processed. This could produce foods with a lower glycemic impact.