Studies On The Identification, Bioactivities And Preparation Procedure Of Components In Sea Cucumber Cooking Water

A large amount of sea cucumber cooking water is produced when cooking sea cucumber at high temperature to inactivate enzymes. Sea cucumber cooking water contains a number of nutrients and bioactive components, such as cucumber polypeptides, polysaccharides, saponins, and unsaturated fatty acids. This research aimed to provide information of valuable ingredients in sea cucumber cooking water, and helped to exploit and re-utilize these processing by-products.Firstly, peptides from sea cucumber cooking water after enzymolysis were studied. Peptides were absorbed by NAK-9 macroporous resin. Then the resin was washed with 30%, 60% and 90% ethanol successively to obtain three fractions which were named as I, II and III. Amino acid analysis showed that the total amino acid contents of â… , â…¡and â…¢ were 73.7%, 81.99% and 59.3%, respectively. They all contained high level of His, Asp and Glu. Antioxidant activities of â… , â…¡and â…¢ were measured by electron spin-resonance spectroscopy(ESR). IC50 for DPPH· radical scavenging activity of â… , â…¡ and â…¢ were 4.35 mg/m L, 11.54 mg/m L and 12.92 mg/m L, respectively; and their IC50 for hydroxyl radical scavenging activity were 11.58 mg/m L, 12.43 mg/m L and 10.28 mg/m L, r espectively. HPLC was used to detect the angiotensin converting enzyme(ACE) inhibitory activity. IC50 for ACE inhibitory activity of â… , â…¡ and â…¢ were 3.01 mg/m L, 0.98 mg/m L and 2.88 mg/m L, respectively. After further separation, polypeptide A and B were purified from â…¡. Molecular weight of A and B were identifed as 4299 Da and 4219 Da by Matrix-Assisted Laser Desorption/ Ionization Time of Flight Mass Spectrometry(MALDI-TOF-MS). IC50 for ACE inhibitory activity of A and B were 0.74 mg/m L and 1.77 mg/m L, respectively.Secondly, polysaccharides and fatty acid of sea cucumber cooking water were studied. PMP derivatization followed by HPLC-MSn analysis was applied to detect the acid hydrolysate of polysaccharides from sea cucumber cooking water. The results show that the polysaccharides mainly contain Man, Fuc, Glc, and Gal, while Man and Fuc are the major component monosaccharides. The existence of chondroitin sulfate(f CS) in the sea cucumber cooking water were confirmed on the basis of the detected disacchari de, Glc A-(1â†'3)-Gal N. Fatty acid composition was analyzed by GC-MS. 9 saturated fatty acids were found and made up 27% ~ 34% of the total fatty acids, 11 monounsaturated fatty acids were detected with a total percentage of 44% ~ 55%, and 8 polyunsaturated fatty acids were observed with 17% ~ 20%.Finally, based on the above analysis results, a technique to fully utilize sea cucumber cooking water was developed after comparison and optimition. Through concentration, ethanol precipitation, freeze drying, getting rid of fat and salt, a product with protein of about 58.77% was obtained. The supernatant of sea cucumber cooking water after ethanol precipitation were absorbed by macroporous adsorption resin, and the purity of prepared sea cucumber saponins is up to 63.51%.