| High temperature cooking and hair cooking are the main processing methods of ready-to-eat sea cucumber.Because there is a layer of attachment on the body wall of sea cucumber,it will directly affect the appearance quality of the final sea cucumber product.In this paper,the effects of blanching,peeling,cleaning and boiling on nutrient content,polysaccharide composition,monosaccharide composition,polysaccharide structure and polysaccharide properties of sea cucumber were studied.At the same time,the effects of peeling and non-peeling processing methods on polysaccharides and other components of sea cucumber body wall were compared.The main research results are as follows:1.In the exudate of sea cucumber from two producing areas,which is treated by four kinds of treatment methods,the solid is mainly composed of salt and protein,accounting for more than 92%,and the polysaccharide is relatively low.From the perspective of polysaccharide exudation,boiling 90 min accounted for the highest proportion(32.8%),followed by peeling 28.3%,cleaning 22.5%,blanching 3 min was the lowest(16.5%).Boiling for 90 min accounted for the highest proportion(35.8%),followed by peeling for 29.5%,cleaning for 19.1%,blanching for 3 min for 19.1%;It can be seen that the four treatment methods have similar rules on the polysaccharide exudate of the body wall of Sticostis japonicus from two places.2.Using the body wall of sea cucumber from Longtengwan as raw material,the body wall of sea cucumber was processed by peeling and non-peeling methods respectively.The amount of polysaccharide,solid,salt and protein oozed from the body wall per unit weight was obviously different.The amounts of polysaccharides,solids,salts and proteins exudated from the body wall of sea cucumber per kg by peeling method were 1.80 g/kg,49.62 g/kg,19.77 g/kg and 28.05 g/kg,respectively.The amounts of polysaccharides,solids,salts and proteins exuded from the body wall of sea cucumis by non-peeling method were 0.89 g/kg,19.17 g/kg,10.02 g/kg and 8.26 g/kg,respectively,which were 2.0,2.6,2.0 and 3.4 times of those by non-peeling method.The results showed that the amount of nutrients exuded from the body wall of sea cucumber by peeling method was significantly higher than that by non-peeling method.3.From the perspective of monosaccharide composition,mannose accounted for the highest proportion of monosaccharides in the four kinds of crude polysaccharides in the body wall of sea cucumbers from the two producing areas of Qianshen Island and Longtengwan,followed by fucose,amino acid glucose and glucose;The proportion of monosaccharides in the crude polysaccharides of boiling solution and peeling solution was higher than that of bleaching solution and cleaning solution.In terms of origin,mannose and fucose were the main crude polysaccharides in the four treated liquids of sea cucumbers from Chingshen Island.Among them,mannose accounted for the highest proportion(2.1% ～7.08%),followed by fucose(1.09～4.73%).There was no significant difference in the proportion of monosaccharides between the peeling solution and the 90 min boiling solution.The proportion of mannose in crude polysaccharide of the four treated liquids of Longtengwan sea cucumber was the highest(4.28-11.09%),followed by fucose(5.44-6.82%),and the contents of amino acid glucose and glucose were similar.4.In terms of antioxidant activity,the DPPH free radical scavenging ability,ABTS free radical scavenging ability and hydroxyl free radical scavenging ability of the crude polysaccharide from the non-peeling boiled solution and the peeling boiled solution were significantly higher than those from the peeling solution and the bleaching solution,indicating that the antioxidant effect of the crude polysaccharide from the boiling treatment was significantly better than that of the other treatments.The free radical scavenging ability of crude polysaccharides in exudate of the four treatments increased with the increase of polysaccharide concentration.5.According to the infrared spectra,the crude polysaccharides of sea cucumbers treated by the four methods all contain acetyl amino and fucose methyl.The O-H bond is obvious,and the C-O bond of uronic acid is also the unique absorption peak of polysaccharide.There was one more absorption peak in 1220 cm-1 in peel solution and oozing solution than in bleach solution and washing solution,which was related to sulfuric acid group.4 components F1,F2,F3 and F4 were obtained by DEAE-52 cellulose anion exchange chromatography.The monosaccharide composition and content of the 4components were significantly different.The percentage of monosaccharide composition of F1 was Man: Glc N: Glc UA: Gal UA: Gal N: Gal: Fuc =1.78:16.45:0.79:4.5:7.21:25.29:27.09;F2 monosaccharide composition quality percentage for Man: Glc N: Gal UA: Gal N: Gal: Fuc =2.34:6.44:6.85:10.56:19.27:1.07:53.47;The mass percentage of F3 monosaccharides is Man: Glc N: Gal UA: Gal N: Gal: Fuc= 4.19:4.44:2.31:4.76:5.45:10.17:67.42;The percentage of monosaccharide composition of component F4 is Man: Glc N: Gal UA:Gal N: Gal: Fuc= 2.95:3.15:0.72:1.72:3.17:5.68:81.75.It can be seen that among the monosaccharides of the four components,fucose accounted for the highest proportion,ranging from 27.09% to 81.75%,and with the increase of elution concentration,fucose proportion increased,while glucosamine proportion decreased.7.Component F2 was further purified by Sephacryl S-300 gel chromatography,and three components N1,N2 and N3 were obtained.The monosaccharide composition percentage of N1 was Man: Glc N: Gal UA: Gal N: Glc: Gal: Fuc= 5.50:4.98:3.48:8.99:14.42:4.52:58.10;N2 monosaccharide composition quality percentage for Man: Glc N:Gal UA: Gal N: Glc: Gal: Fuc = 6.13:1.41:0.98:12.09:8.14:5.68:65.58.The mass percentage of N3 monosaccharides is Man: Glc N: Gal UA: Gal N: Glc: Gal:Fuc=4.28:2.49:2.00;5.46:6.77:4.99:74.01.Among the three monosaccharides,fucose accounted for the highest proportion,ranging from 58.10%-74.01%,and with the extension of elution time,fucose proportion increased and glucose proportion decreased.8.The relative molecular weights of components N1,N2 and N3 were determined by high-performance gel rejection chromatography.N3 had one main peak with a relative molecular weight of 347.04 k Da,N1 had one main peak with a relative molecular weight of 312.17 k Da,N2 had two peaks with a relative molecular weight of53.47 k Da.The molecular mass of the second peak was 226.05 k Da.In summary,the four different treatment methods and processing methods have obvious effects on polysaccharide content,polysaccharide monosaccharide composition,polysaccharide structure and polysaccharide properties of sea cucumber,which provide theoretical reference for the optimization and innovation of sea cucumber processing technology. |
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