| The swimming crab wastes were by-products which wee produced during the processing of the swimming crab product(frozen crab meat,crab carapace,crab spawn paste and crab-sauce),which consists of crab tergum,crab claws and viscera. The main components of swimming crab wastes are protein,crab oil and mineral. This research takes the swimming crab wastes as raw material,the crab oil was extracted firstly,then the protein was extracted,and the protein hydrolysate was processed to protein powder and seafood condiment,the enzymatic-hydrolysis waste of swimming crab was made into crab shell micro-powder by ultrafine technology at last.Accordingly,the waste-free comprehensive processing technology of swimming crab waste was accomplished basically.The aforesaid comprehensive processing technology was studied in this work.(1)The crab oil was extracted from swimming crab waste by solvent method, and processed to refined crab oil,the physicochemical properties and fatty acid composition of refined crab oil were analyzed.The results showed that anhydrous ethanol was the best extraction solvent for crab oil,and the optimal extraction conditions were that:temperature 75℃,time 60min,ratio of solvent to material 5:1; The crude crab oil was refined by degumming,deacidification and decoloration,. successively;The content of SFA was 41.79%,UFA was 56,94%,the content of DHA and EPA was 10.50%and 1.03%,respectively.The physical and chemical indexes of refined crab oil accorded with the first refined fish oil demand of SC/T3502-2000 fish oil standard.(2)The protein hydrolysate was extracted from defatted swimming crab waste by enzyme hydrolysis and processed to protein powder,the quality of protein powder were analyzed.The result showed that the best hydrolytic proteinase for swimming crab waste is alkaline proteinase.The optimal hydrolysis conditions were that:temperature 55℃,pH 8.5,added enzyme 1000u/g,time 3.0h and ratio of solution to material 3:1;The total content of aminoacid was 1046.7mg/L,8 essential amino acids 382.5mg/L accounting for 36.54%of the total amino acid,4 flavor amino acids 412.6mg/L accounting for 39.42%of the total amino acid.The protein hydrolysate of swimming crab waste was processed to protein powder by spray-drying.The protein powder was light yellow and had strong crab flavor,the taste was slight bitterafter solution;Its molecular weight was less than 10kDa;The content of protein in the protein powder was 72.23%,fat 0.12%,moisture 5.18% and ash 12.58%;Various index of protein powder was accorded with the standards of QB 2732-2005 hydrolytic collagen except protein and ash.(3)The hydrolysate was extracted from defatted swimming crab waste by compound enzyme hydrolysis,then processed to seafood condiment,the quality of seafood condiment was analyzed.The result showed that complex of neutrase and flavourzyme was suitable for the hydrolysis of swimming crab waste.The optimal hydrolysis conditions were that:temperature 50℃,pH 7.0,the amount of enzyme 1200u/g,time 3.0h,ratio of neutrase to flavourzyme 2:1 and ratio of solution to material 3:1;the amin o acid content of the hydrolysis were:The total content of amino acid was 1395.0mg/L,8 essential amino acids 496.7mg/L accounting for 35.61%of the total amino acid,4 flavor amino acids 554.9mg/L accounting for 39.78%of the total amino acid.The optimal formula of seafood condiment was that:common salt 10%,granulated sugar 5%,monosodium glutamate 5%,ginger powder 0.2%and modified starch 1.0%;Indexes of microorganism,physical and chemical of production were accorded with the hygienic standards of GB 10133-2005 aquatic condiment.(4)The functional properties and antioxidant properties of hydrolysate of swimming crab waste were studied.The result showed that the hydrolysates shows good emulsifying properties and foaming properties,solubility was higher than 94%,WAC and FAC was 37.76%and 60.58%,respectively;Furthermore,the hydrolysates shows good antioxidative activity,the reducing power of 0.5% hydrolysates almost has the same values as 0.05%ascorbic acid,the·OH scavenging rate and·O2-scavenging rate show dose-dependent fashion,and their highest rate of free radical scavenging were 43.27%and 55.91%,respectively.(5)The enzymatic-hydrolysis waste of swimming crab waste was made into crab shell micro-powder by ultrafine technology,then its powder properties and nutrient content were studied.The result showed that the optimal conditions of superfine grinding were that grinding time 10min,tuyere angle 45°,moisture content of feeding material 5%and feeding material sizes 40 grit number;The average granularity of crab shell micro-powder was 21.65μm,angle of repose 53.16°,dissolved solubility 10.46%and dissolving out rate of protein 37.69%; The content of protein in the crab shell micro-powder was 29.4%,fat 0.12%and ash 60.7%.Therefore,the crab shell micro-powder had the characteristics of higher protein,lower fat and abundant minerals;The content of Ca was 326mg/g,P 176mg/g and Fe 24mg/g,the ratio of Ca and P was 1.85:1;The total content of amino acid was 10.55%,8 essential amino acids was 3.32%,which accounted for 45.05%in the total amino acid.The crab shell micro-powder could be used as a good food additive and the most suitable additive rate in the bread of crab flavor was 2.0%.The result showed that swimming crab waste has high developing value.The oil in swimming crab waste is a sanitarian seafood oils with abundant MUFA, especially DHA and EPA.There are a great deal of active peptide and essential amino acids in the hydrolysate.It has a full-bodied seafood flavor,good functional properties and antioxidative activity.It will be a perfect material for health-food and seafood condiment.The crab shell micro-powder had the characteristics of higher protein,lower fat and abundant minerals,and could be used as a good additive of mineral supplement.
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