Effect of fishing method on the quality of katsuobushi

Abstract

  The sliced fushi manufactured from the raw materials caught by pole and line (SK-PL) and purse seine (SK-PS) were examined in terms of yield of powder in the manufacturing process, bulk, pressure-resistant strength, and inosine 5′-monophosphate (IMP) content, and the muscle tissues of both katsuobushi were also analyzed histochemically using eosin-Y staining.
  In comparison with SK-PS, SK-PL yielded a significantly lower percentage of the powder (p<0.05), and possessed a significantly higher value (p<0.05) in the bulk, the pressure-resistant strength, and the IMP content, indicating that SK-PL had clearly higher quality than SK-PS.
  Histochemical analysis revealed that the ratio of eosin-Y positive components (EPC) remaining in muscle cells of SK-PL was higher than that of SK-PS. We also found that the EPC-existing situation index (ASPC) estimated from the quantity and the quality of EPC in muscle cells was closely correlated with the yield of powder, the bulk, and the IMP content of the sliced fushi.
  These results suggested that the ASPC was a suitable index to judge the quality of katsuobushi, and a useful tool for studying the development of the manufacturing process to produce a high quality katsuobushi from the raw materials caught by purse seine.