Quality Evaluation of Fish Meat by 31 Phosphorus‐Nuclear Magnetic Resonance

ABSTRACT 31 Phosphorus‐Nuclear Magnetic Resonance ( 31 P‐NMR) was used to evaluate degree of freshness of loach muscle depending on metabolic changes of high energy phosphate compounds. The phosphocreatine ([PCr])/inorganic phosphate ([Pi]) ratio was found to be a sensitive index of early metabolic hypofunction. Ratios of [PCr]/β‐phosphate of ATP ([β‐ATP]), and [Pi]/[β‐ATP] were demonstrated to be appropriate indexes to estimate such metabolic changes in fresh fish. The intramuscular levels of creatine phosphate, ATP and pH were maintained at higher levels in blood‐drained loach than in untreated fish. The freshness of fish which were bled and washed at lower temperatures were better preserved.