Effects of Handling Processes on the Quality and Biochemical Changes in Tissue of Mud Crab, ( Scylla serrata, Forsskål, 1755) During Emersion Storage

Abstract

The effects of handling processes were investigated in the mud crab, Scylla serrata, using pre-cooling and chelae tying during emersion storage.Muscle glycogen, muscle lactate, muscle yield, muscle pH, volatile basic nitrogen (VBN), and chemical composition were analyzed. More than 90% of the glycogen in muscle of non pre-cooling without chelae tying and non pre-cooling with chelae tying disappeared within 3 days of emersion storage, while the concentration of glycogen following non pre-cooling with chelae tying and pre-cooling with chelae tying decreased by only about 70% within the same period of time. Lactate content increased from the initial level - 1.20 ±0.20mmol/kg - to 14.81±0.28mmol/kg in non pre-cooling without chelae tying, while it increased to 11.34±0.58mmol/kg, 11.12±0.27mmol/kg and 10.08±0.62mmol/kg during treatment including non pre-cooling with chelae tying, pre-cooling without chelae tying, and pre-cooling with chelae tying, respectively. The muscle pH of all treatments remained almost unchanged, irrespective of treatment. Percentage loss of muscle yield after 7 days was 30.10±1.20%, 20.95±3.90%, 22.32±4.26% and 17.29±4.93% in non pre-cooling without chelae tying, non pre-cooling with chelae tying, pre-cooling without chelae tying, and pre-cooling with chelae tying, respectively. The volatile basic nitrogen (VBN) levels of the non pre-cooling without tying was 60.12±3.36 mgN/100g which is significantly different from the levels of the pre-cooling with chelae tying treatment (48.00±4.38 mgN/100g). None of the treatments resulted in any significant changes in mean of moisture, protein, fat, or ash content. The results indicated that the handling process including pre-cooling with chelae tying could reduce metabolic activity and metabolic stress, which could delay loss of quality and physiological changes of mud crab during emersion storage.