Imitation crab stick from soy protein isolate: Part I Factors affecting soy protein isolate gel

Three factors, i.e., soy protein isolate (SPI) concentration (15, 17.5 and 20% w/w), incubation time (0, 5, 10 and 15 minutes) and transglutaminase (TG) concentration (0.1, 0.2 and 0.3% w/w) were used to investigate their effects on texture characteristics of the SPI gel. The results showed that increase of SPI concentrations resulted in a significant increase of hardness, adhesiveness and cohesiveness (p<0.05) whereas incubation time showed no significant effects on all the textural properties (p>0.05). SPI at a concentration of 17.5% (w/w) provided the gel having textural characteristics similar to those of the commercial imitation crab stick. However, the texture was slightly crumbly. TG was then used in combination with SPI to improve firmness and cohesiveness. It was found that TG significantly improved SPI gel’s texture. Based on the sensory result and textural properties, the SPI based gel formed from a combination of 17.5%-SPI and 0.1%-TG was suggested for the production  of  SPI  based  imitation  crab  stick.  The  gel  from aforementioned condition showed hardness, adhesiveness, cohesiveness, and springiness values of 7.18±0.51 N, -0.47±0.14 N∙s, 0.88±0.00 and 95.58±0.43% respectively. The resulting gel had light yellow color with slightly shiny surface. Besides, surface of the gel was smoother than that of gel formed without TG. Sensorial results indicated that the texture of the SPI gel was moderately firm and elastic like imitation crab stick and
it was slightly like by the panelists.