The effects of endogenous proteases within abdominal muscle parts on the rheological properties of thermally induced gels from white croaker (Pennahia argentata)

Three types of material meats were prepared from a so-called normal muscle part of white croaker (Pennahia argentata) containing 0, 4.2 and 8.4% of an abdominal muscle part. Thermally induced gels were then prepared from these materials by pre-heating at 65 °C for 30 or 60 min and subsequent heating at 85 °C for 20 min. The breaking strength and breaking strain rate of thermally induced gels decreased with increasing contamination levels of the abdominal muscle part, in which degradation of myosin heavy chains was observed. The proteolytic activity in the abdominal muscle part homogenate was highest at 62.5 °C. These results suggest that the abdominal muscle part contains proteases that induce the modori phenomenon. Technical experts assume that a contaminated abdominal muscle part leads to quality deterioration in surimi production industries. Our findings will aid the production of high-quality surimi-based products.