EnvironmentAsia (Jul 2008)
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±0.20 mmol/kg - to 14.81±0.28 mmol/kg in non pre-cooling without chelae tying, while it increased to 11.34±0.58 mmol/kg, 11.12±0.27 mmol/kg and 10.08±0.62 mmol/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.
