Tärkkelysjyvänen

Tärkkelysjyvänen, also known as a starch granule, is a semi-crystalline particle found within plant cells that serves as a storage form of starch. These granules are composed of amylose and amylopectin, two different types of polysaccharide polymers of glucose. The precise ratio of amylose to amylopectin, along with their arrangement within the granule, determines the physical and chemical properties of the starch, such as its solubility, gelatinization temperature, and digestibility.

Tärkkelysjyväset are typically formed within plastids, specifically amyloplasts, in various plant tissues, most notably in storage organs like roots, tubers, seeds, and fruits. Their structure is often characterized by concentric layers, which are thought to represent periods of growth and deposition. The size and shape of tärkkelysjyväset can vary significantly depending on the plant species and even the specific organ within a plant, ranging from very small, irregular shapes to large, distinct ovals or spheres.

When plants need energy, enzymes like amylase break down the tärkkelysjyväset into glucose molecules. In food science and industry, tärkkelysjyväset are crucial. They are extracted from plants and used as thickeners, stabilizers, and texturizers in a wide array of products, including baked goods, sauces, and processed foods. The process of cooking with starch, such as in making pudding or gravy, involves the gelatinization of these granules, where they absorb water, swell, and lose their crystalline structure, leading to thickening.