Chemical composition and flavour characteristics of a liquid extract occurring as waste in crab (Ovalipes punctatus) processing.
BACKGROUND
The crab processing industry has generated a considerable quantity of by-products, and these untapped residues resulted in environmental problem and waste of natural resources. Therefore, the purpose of this research was to evaluate the further usage potential of Ovalipes punctatus extract. The proximate composition, minerals, fatty acids, amino acids, tasty components (free amino acid, flavour 5'-nucleotides, glycine betaine and inorganic ions) and volatile flavour components were studied.


RESULTS
O. punctatus extract was found to have a high protein (31.2 g kg⁻¹), but a low fat content (0.13 g kg⁻¹). The protein contained high amounts of arginine (110.2 g kg⁻¹ protein) and glutamic acid (108.9 g kg⁻¹). The fatty acid profiles were dominated by saturated fatty acids, while C20 n-3 and n-6 fatty acids accounted for 85% of its polyunsaturated fatty acids. Arginine, alanine, glycine, glycine betaine, glutamic acid and chloridion (taste active value greater than 1) were primary taste-active components. A total of 77 volatiles were identified, and benzaldehyde and pyrazines were the major flavour contributors to the aroma of O. punctatus extract. Furthermore, sensory evaluation with a five-point hedonic scale showed that the overall flavour of O. punctatus extract had high acceptance.


CONCLUSION
Results presented in this study indicated that O. punctatus extract could be utilised to produce nutritious food or value-added products.