People/Faculty/Wang

	Shaw S. Wang Professor & Director of Undergraduate Program B.S., Agricultural Chem., National Taiwan Univ., 1963 M.S., Food Science, Rutgers University, 1969 Ph.D., Food Science, Rutgers University, 1970 Tel: (732) 445-3360 Fax: (732) 445-2581 email: shaww@sol.rutgers.edu

Kinetics of food extrusion, integrated cell culture and downstream processing system.

Extrusion is a uniquely energy efficient process. Its application in food industries is relatively recent and the practice is one of trial and error. Fundamental studies are underway to elucidate the chemical and physical changes of biomaterials under extrusion conditions as affected by thermal and mechanical energy inputs. In the typically fast process of extrusion, appropriate kinetic equations are formulated to model the process. An energy equivalent concept has been developed to treat the interacting effect of thermal and mechanical (shear) energy inputs. The conversion induced by mechanical energy has, in contrary to that by thermal energy, a negative temperature coefficient. Tribologically induced changes are unique to extrusion process. Fundamental studies of the tribochemistry of starch, protein, lipids and their inter-actions are important to the design, operation and control of food extrusion processes.

The growth and maintenance of animal cells in vitro as a suspension culture requires special bioreactors. Mouse-mouse hybridoma cells can constitutively produce monoclonal antibodies under appropriate conditions. High cell densities (>5x106 cells/ml) will lead to much higher productivity of antibody. A perfusion system is best suited for continuous operation of a high cell density reactor. One system utilizing a hollow fiber cartridge with a microporous membrane in a tangential flow mode of operation permits retention of cells in the reactor so high cell densities can be achieved. Long term persistent shear force generated by the cell retention devices (recycle pump and hollow fibers) greatly contribute to cell damage and cell death. These effects should be quantified and considered for operation of the perfusion system. A bleed stream can be introduced to control cell growth rate and to maintain proper operation. The ultimate goal of this research is to produce large quantities of a cell-free product which can be easily integrated with an on-line downstream purification system. The purification scheme consists of precipitation and ultrafiltration stages along with affinity or ion exchange chromatography stages. Relatively pure antibodies can then be produced on a regular basis.