Trace element-based food value evaluation in soft and hard shelled mud crabs

Area of Science:

• Marine Biology
• Analytical Chemistry
• Food Science

Background:

• The nutritional and safety profiles of edible crustaceans are crucial for human consumption.
• Molting is a critical physiological process in crustaceans like Scylla serrata, potentially altering tissue composition.
• Understanding elemental changes during molting is key to assessing food value.

Purpose of the Study:

• To analyze the elemental composition of Scylla serrata during different molting stages.
• To compare the nutritional and safety aspects of pre-molt hard-shelled crabs versus newly moulted soft-shelled crabs.
• To evaluate the suitability of Scylla serrata for human consumption based on elemental analysis.

Main Methods:

• Utilized Energy Dispersive X-ray Fluorescence (EDXRF) to quantify 10 elements.
• Analyzed elemental concentrations in the carapace of hard-shelled crabs.
• Examined elemental concentrations in the body tissues and exuvium of soft-shelled crabs.

Main Results:

• Essential elements (K, Ca, Mn, Cu) are reabsorbed from the carapace into body tissues during soft-shell formation.
• Toxic elements, such as lead (Pb), are excreted during the molting process (exuviation).
• Zinc (Zn) levels are regulated, decreasing when bioavailability increases, ensuring safety.

Conclusions:

• Freshly moulted soft-shelled Scylla serrata exhibit a superior nutritional and safety profile compared to hard-shelled crabs.
• The molting process effectively removes toxic elements and optimizes essential nutrient levels for consumption.
• Soft-shelled crabs represent a safer and more nutritious seafood option for consumers.