gelatinisatieonset

Gelatinisatieonset, or gelatinization onset, is the temperature at which starch granules begin to absorb water, swell, and disrupt their crystalline structure during heating in a moist environment. This marks the initial stage of gelatinization, a process in which granules become more permeable and undergo molecular changes that can include limited leaching of amylose into the surrounding matrix. The onset is distinct from the peak gelatinization temperature and is typically identified as the onset point of the endothermic transition in calorimetric measurements or as the first signs of structural change under microscopy.

Typical onset temperatures vary with starch type and conditions. For common food starches, onset commonly falls within roughly 50 to 70°C. Potato starch often begins around the upper 50s of Celsius, while corn and tapioca starches typically show onset near 60–65°C, with individual samples and processing conditions shifting these values.

Several factors influence gelatinization onset. The starch source and its amylose to amylopectin ratio, granule integrity, and damaged starch content affect To. Water content and heating rate are important: higher moisture generally lowers the temperature at which gelatinization begins, whereas rapid heating can shift apparent onset. Additives such as lipids, sugars, acids, or salts can also shift onset by altering granule swelling, crystalline stability, or amylose migration.

Measurement methods include differential scanning calorimetry (DSC), which provides an onset temperature (To) of the gelatinization endotherm, and polarized light microscopy, where the loss of birefringence signals the beginning of granule disruption. Understanding gelatinisatieonset is relevant for cooking, baking, and industrial processing to control texture, viscosity, and texture development in starch-based products.