| Natural casing can be edible Packaging of sausage and ham, tissue engineering materials in vivo, and so on. As a high-tech food processing, HHP(Hydrostatic High Pressure) technology has been widely used in food areas at present. The properties (include color, mechanic properties and Basic physical properties) of natural casings under deferent pressure levels(10G-600 MPa), pressure medium temperature(20-45℃)andpressure holding time(5-30 min) were investigated via single factor method in this paper, and through observing surface and micro structure of the casings with or without high pressure, the mechanism in the properties of natural casing would be initial explored.The results showed: (1)The effects of changes in pressure levels(100-600 MPa ) and pressure medium temperature(20-45℃) on△a and△b of casings were limited (Value < 2); however, when pressure medium temperature at 20℃. pressure above or equal 200 MPa can significantly increase△L and△E of hog casings(p<0.05),therefore, HHP process may become a measure in casing whiten. (2)HHP treatment will lead to the thickness of hog casing decreased more than 25%. But the changes of pressure levels(100 to 600 MPa) and pressure medium temperature (20 to 45℃) have no significant effects on thickness variation rate of casings(p> 0.05). (3)At lower pressure medium temperature (20℃) the shearing strength and tensile strength of pressurized casings were markedly enhanced under 300 - 600 MPa (p<0.05). which would provide a feasibility for applying casings to tissue engineering. But at higher pressure medium temperature(45℃), the shear strength and tensile strength of casings were significantly reduced by 300 MPa pressure(p<0.05). (4)Pressure holding time have no significant effect on the mechanical properties, colors and thickness of natural casing. The fibers of hog casing under 300 - 600 MPa high pressure treatment were more dense; while pressure medium temperature at 45℃, casings structure were obviously injured by high pressure.
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