Abstract
The effects on cookies of using roasting, deep-frying, steaming, and microwave heating methods are described. The degree of gelatinization and texture of the cookies were measured, and a sensory evaluation was made after controlling the moisture content. The differences in hardness was minimal among the different heating methods under a moisture condition of R.H. 23%, but the cookies tended to become harder in the order of roasted<deep-fried<microwave-heated<steamed at R.H. 88%. A hardening peak appeared with a water content in the ranged of 9-16 g/100 g of dry matter. The sensory evaluation rated, both the steamed and microwave-heated samples as being hard and chewy in texture. The results of this sensory evaluation and the breaking properties at R.H. 88% were highly correlated. High correlation was also apparent between the degree of gelatinization (the level of starch solubility, etc.) and the breaking properties at R.H. 88%. It is considered that microwave heating had affects of, both wet-heating (like steaming), and dehydration, easily promoting the hardening phenomenon.
