Instantaneous High Pressure Process: Its Sterilization Mechanisms And Effect On Quality Improvement And Property Changes Of Dietary Fiber

The new process of " instantaneous high pressure (IHP)" is based on high velocity jet homogenization, in which object are sterilized and ultramicro-pulverized. The key of this process is enormous impulsive pressure changes (>100 MPa) during the very short time frame (less than 1 × 10^-3 second) the material passing through the reactor. During this process, the microorganism and/or other materials are subjected to high-speed impaction, vortex, sudden pressure change, and the associated small rise of temperature, etc. The thesis is intended to study the IHP sterilization mechanisms and the effect of IHP on the properties of dietary fiber.Using yeast, E. coli, B. sbutilis, Bacillus stearothermophilus, and α-amylase as testing organisms, the sterilization effect was investigated. Use B. subtilis as an example, the effect of IHP sterilization on the basic components in food was studied and the dynamic model was developed using the response surface analysis technique. This should provide important background knowledge for farther study and development of the IHP sterilization.The IHP process was also used to modify the physical properties (particle size distribution, rheological properties, solubility, adsorption of metal ions and bile sodium) of enzyme pretreated soybean meal dietary fiber (DF). The application of IHP-treated soybean meal DF in bread was also accomplished. Fluid dynamics behavior of high velocity jet homogenizer was analyzed, which is essential in understanding the reaction mechanisms of the instantaneous high pressure processing. Reaction mechanisms and biological effects of IHP technology are described. This should provide some theoretical bases for new process and equipment development for sterilization, ultramicro-pulverization, cell disruption, and emulsification, etc.In IHP reaction mechanism and its sterilization effect, the concept of IHP is proposed. The purpose and significance of the concept is described. Brief introductions are given to the relation between IHP and homogenization, and the differentiation between IHP and high hydrostatic pressure (HHP). Compared with the high pressure homogenization process, the change of pressure and energy in the high hydrostatic pressure process was analyzed and...