Ultra-high pressure (UHP) was applied as a pretreatment to extract gelatins with 1% (w/v) hydrochloric
acid as the transmission medium at a skin/solution ratio of 1:1.5 (w/v). The effects of various pressures
(ranging from 0.1 to 500 MPa) on the gelatinization of collagen and the properties of the extracted
gelatins were investigated. The thermostability of the pressurized collagens and the yield, molecularweight
distribution, gel strength and rheological properties of the extracted gelatins were evaluated.
UHP pretreatment could decrease the thermostability and enhance the extent of gelatinization of the
collagen. The temperature at which the major endothermic peak was observed (Tm) decreased as the
pressure level increased from 100 to 400 MPa but increased as the pressure reached 500 MPa, whereas
the opposite trend was observed for the gelatins yields. The UHP gelatins contained more subunit
components than traditional gelatin, which increased in content with increasing pressure up to 300 MPa;
the amount of subunit components remained nearly constant when the pressure was further increased.
The gel strength and rheological properties of the UHP gelatins were better than those of traditional
gelatin, and they exhibited similar tendencies to those of high-molecular-weight gelatins with increases
in the pretreatment pressure.