Abstract
We investigated the effects of α-casein (α-CN) and sodium caprate (NaC10 : 0) on the formation of mixed gels with ovalbumin (OVA) using rheological measurement, ultrasound spectroscopy, flourier transform-infrared (FT-IR) analysis and scanning electron microscopy (SEM) observation. Although α-CN shows quite heat-stable rheological properties during the heating process, the mixture formed a soft gel with or without NaC10 : 0. In the presence of NaC10 : 0, the mixture shows a clear sol-gel transition, which is different from those in the absence of NaC10 : 0. The ultrasonic gradient velocity between α-CN/OVA+NaC10 : 0 and OVA+NaC10 : 0 mixed systems indicated that the effects of α-CN addition began at around 46°C for the formation of a unique gel from the mixed protein system. FT-IR analysis indicated a decrease of 310-helices, α-helices, and β-sheets by the addition of NaC10 : 0, and α-CN/OVA+NaC10 : 0 showed a characteristic spectrum which is different from that of the OVA+NaC10 : 0 system. The results imply that the mixed protein system containing milk casein is an interesting material for creating processed foods with novel texture and appearance.
