Effect of dietary fibre and MTGase on the quality of mackerel surimi gels

BACKGROUND: The effects of microbial transglutaminase (MTGase; 5 g kg(-1)) and dietary fibre (inner pea fibre and chicory root inulin, 20 and 40 g kg(-1)) on gels from surimi made with Atlantic (Scomber scombrus) and chub mackerel (Scomber japonicus) were studied with the purpose of achieving a better understanding of the underlying phenomena and improving gels. RESULTS: MTGase addition improved textural properties (namely, cohesiveness increased from 0.19-0.41 to 0.59-0.72) and increased PH and water-holding capacity (WHC). Moreover, MTGase reduced the elastic and viscous modules and darkened gels; protein solubility declined, meaning greater protein aggregation, according to electropherograms. MTGase had no unequivocal effect upon the gels' microstructure. Pea fibre increased hardness (an increase of almost 60% with 40 g kg(-1)) and related parameters, the elastic and viscous modules and WHC. Pea fibre reduced extractable protein in sodium dodecyl sulfate and urea (in the absence of MTGase) as well. Scanning electron microscopy revealed different structures for gels containing pea fibre. Regarding inulin, it worsened textural quality and WHC. CONCLUSION: A combination of MTGase and pea fibre can improve a poor quality surimi. (C) 2009 Society of Chemical Industry