Abstract:

This research studied the effect of different microwave power levels on foaming, emulsifying and gel properties
of soybean protein isolate-phospholipid system by measuring foaming activity, foam stability, emulsifying activity, emulsion
stability, flocculation index, creaming index, water retention and gel texture, as well as by examining gel microstructure
under scanning electron microscope. The results showed that foaming activity, emulsifying capacity and gel properties
were increased at first and then decreased with microwave power. In addition, when the microwave power was 900 W, the
composite system exhibited the best foaming properties and emulsifying properties; at 1 100 W microwave power, the gel
properties were improved significantly when compared with the control sample, indicating that microwave could promote the
formation of soybean protein isolate-phospholipid system at the water/oil interface and that structural changes of the protein
could improve gel properties of the composite system.

Key words: soybean protein isolate, phospholipid, microwave treatment, functional properties