Wheat Pregelatinized Starch possesses strong hygroscopicity and tends to cake under humid environments, with higher caking risk than native wheat starch. This inherent property stems from its modified molecular structure. Storage conditions and ambient humidity determine the severity of caking. The formation mechanism, characteristics of caked starch and prevention approaches are elaborated below.
Structurally, native wheat starch has compact, regularly arranged granules with relatively closed surfaces and low hygroscopicity. After high-temperature gelatinization, drying and pulverization modification of Wheat Pregelatinized Starch, dense granular structures break down, molecular chains fully extend, internal pores increase and numerous hydrophilic polar groups appear on surfaces. The specific surface area expands sharply and moisture adsorption capacity improves drastically. When air humidity rises, packages are poorly sealed or goods are left uncovered, starch powder rapidly absorbs moisture. Surface particles soften after water uptake, adhere to each other and gradually form lumps.
Two levels of caking can be distinguished: light and severe. Light caking generally arises from short-term surface moisture exposure. Only surface powder agglomerates while internal material stays dry. Lumps are loose and can be broken up by stirring or sieving. Hydration, thickening and binding performance remain largely intact for normal production use. Severe caking occurs when goods are stored uncovered for a long time, stacked in high-humidity warehouses or packages break and allow water ingress. Powder absorbs moisture thoroughly and hardens into solid chunks. Molecular colloidal structures are damaged, slowing dissolution and drastically reducing viscosity. Hard undissolvable cores often emerge, resulting in complete loss of core functions and rendering the material unusable.
Multiple influencing factors exist. Ambient humidity serves as the primary trigger; caking probability rises significantly when relative humidity exceeds 65%. Storage methods including open placement, stacking against walls or floors and storage in hot, humid enclosed warehouses accelerate moisture absorption and caking. Caking can be effectively avoided by strictly complying with sealed, dry and ventilated storage standards to isolate moisture. Keep unopened Wheat Pregelatinized Starch in intact original packages inside low-humidity dry warehouses. Immediately seal packages after opening, avoid open storage and stay away from water and damp areas. Lightly caked material does not require disposal and can be reused after loosening. Only severely dampened, hardened batches must be discarded, making caking controllable with proper management.
