Aggregation/gelation of the SPI-GDL system was continuously monitored by a colorimeter (Chroma Meter; CR-100, Minolta Co.). Changes,in tristimulus values L*, a* and b* as affected by temperature, preheat treatment, protein and coagulant concentration were investigated. Observed L* gelation curves were well approximated by first-order reaction kinetics. Lightness L* of the gelled material was not greatly influenced by any of the above-mentioned parameters except preheat treatment. Increasing protein concentration decreased the rate of gelation, while the other parameters enhanced it. Values a* and b* may be related to the size of the aggregating protein particles.