Emulsifying and gelling properties of porcine blood plasma as influenced by high-pressure processing

The emulsifying properties and the characteristics of heat-induced gels (texture and water-holding capacity) prepared from pressurised blood plasma solutions of different pH (5.5-7.5) were investigated. Changes in the plasma, that affected its behaviour as an emulsifier, occurred after pressurisation. The highest emulsifying activity was found for samples treated at 400 MPa. At pressures above 400 MPa, the emulsifying activity and stability, at all pHs, decreased with increasing pressure. The hardness of heat-induced gels decreased significantly as the pressure increased above 400 MPa, this effect being more noticeable with decreasing pH. However, although a 600 MPa pressurisation induced a further decrease in the firmness of gels from solutions at pH 6.5 and 7.5, it increased the hardness of gels at pH 5.5. For treatments up to 500 MPa, the highest elasticity was found in gels from solutions at pH 7.5. Pressure treatments above 400 MPa improve the water-holding capacity of heat-induced gels prepared from plasma solutions at pH greater than or equal to6.5. (C) 2001 Elsevier Science Ltd. All rights reserved.