• Fisheries and Aquatic Sciences
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• v.20 no.7
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• pp.13.1-13.7
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• 2017

In order to evaluate the maximal storable period of the raw crab for a non-thermal muscle separation, the quality changes of the leg meat of red snow crab (Chionoecetes japonicus) during freeze storage were investigated. Fresh red snow crabs were stored at $-20^{\circ}C$ for 7 weeks, and the leg muscle was separated by a no heating separation (NHS) method every week. During the storage, considerable loss of the leg muscle did not occur and microbiological risk was very low. In contrast, discoloration appeared at 2-week storage on around carapace and the leg muscle turned yellow at storage 3-week. In physiochemical parameters, protein and free amino acids gradually decreased with storage time, expected that proteolytic enzymes still activated at $-20^{\circ}C$. At 4-week storage, the sensory acceptance dropped down below point 4 as low as inedible and notable inflection points in pH and acidity were observed. The volatile base nitrogen was low, though a little increase was recorded. These results suggested that the maximal storable period at $-20^{\circ}C$ of the raw material was within 2 weeks and it was depended on external factor such as the discoloration. The present study might be referred as basic data for approaches to solve quality loss occurred in non-thermal muscle separation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.284-292
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• 2015

We explored preprocessing-mediated quality changes in red snow crab fish sauce. A control (C) group and groups treated with autolysis (A), boiling (B), enzymatic hydrolysis (E), and addition of Aspergillus oryzae (K) were formed. The titratable acidity of the K group increased with storage time, whereas that of groups C, A, B, and E decreased. The total and amino nitrogen contents initially increased on storage of all samples, but decreased in later periods. The total plate count (TPC) of the K group was initially 5.26 log CFU/mL and increased to 7.28 log CFU/mL at 3 months of storage. The TPCs of the C, A, B, and E groups were initially <5.00 log CFU/mL and decreased with storage. The lactic acid bacteria count of the K group was initially 4.80 log CFU/mL and increased until month 5 to approximately 6.06 log CFU/mL. The K group scored higher in terms of sensory attributes than the other groups and maintained marketable scores for all relevant properties (color, flavor, off-odor, and overall acceptance). Furthermore, the free amino acid content of the K group was the highest among all groups at approximately 3,000 mg per 100 g. These results suggest that K treatment may be beneficial in the preparation of fermented fish sauce.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.41 no.2
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• pp.119-124
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• 2008

Reproductive ecology of the snow crab Chionoecetes opilio was investigated in terms of the reproductive organs, abdominal flap, fecundity, and maturity. Specimens were collected with gill nets and trawls from June 2002 to May 2003 in the eastern waters of Korea. The female and male C. opilio are distinguished only by the shape of the abdominal flap, which is triangular in males and circular in females. The gonads of female and male crabs are generally X-shaped. The male gonad is white, while the female gonad appears milk-white after spawning and then turns from light orange to dark orange with maturation. The female gonads matured from June, and mature and immature groups could be distinguished from December to February or March. Brooding eggs changed from bright orange to dark brown with formation of the compound eye immediately before hatching. Accordingly, the main spawning season is February and March. The minimum maturity carapace width of female crabs was 61.1 mm, and the mean fecundity is about 108,300 eggs.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.2
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• pp.221-227
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• 2023

The vertical distribution of snow crab Chionoecetes spp. larvae in the East Sea were investigated in April 2021 using the Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS). The water temperature ranged from 0.86 to 17.2℃, and salinity from 34.0 to 34.7 psu. Zoea I and II occurred range from 29 to 1,982 inds.10³ m^-3 at 10 stations, and range from 4 to 11 inds.10³ m^-3 at 3 stations, separately. Therefore, Zoea I occurred in wider area and higher density than Zoea II at all stations. In the vertical distribution of larvae, all zoeal stages were mainly distributed in the 30-40 m strata, and the larvae showed nocturnal vertical migration similar to that of most zooplankton. Zoea I appeared in the range from 13.7 to 15.8℃ and occurred at the highest density of 1982 inds.10³ m^-3 at 14℃. And Zoea II appeared range from 13.4 to 14.5℃ and occurred in the highest density of 11 inds.10³ m^-3 at 13.4℃. In conclusion, the early larval stage (zoea I) occurred at a higher range of sea surface temperature than later larval stage (zoea II).

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.151-153
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• 2001

• Proceedings of the Korean Aquaculture Society Conference
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• 2004.05a
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• pp.378-378
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• 2004

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.437-440
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• 2006

To develop natural crab-like flavorants from red snow crab Chionoecetes japonicus cooker effluent (RSCCE), the flavor was analyzed during the concentration of RSCCE up to $40^{\circ}Brix$. Using solid phase microextraction (SPME)/gas chromatography (GC)/mass selective detection (MSD), 30 volatile flavor compounds were detected in four RSCCE samples (10, 20, 30, and $40^{\circ}Brix$). These comprised 12 aromatic compounds, 5 N-containing compounds, 2 5-containing compounds, 2 alcohols, 2 aldehydes, and 7 miscellaneous compounds. The amounts of all volatiles except alcohols and aldehydes increased significantly with the concentration (p<0.05). Of the volatiles detected, the most abundant was a dimethyl trisulfide with an odor like onion/cooked cabbage. Of the N-containing compounds (nutty, roasted peanut-like odor), 2-ethyl-5-methylpyrazine was the most abundant, followed by 2,5-dimethylpyrazine and 2-methyl-5-isopropylpyrazine in that order (p<0.05). The N- and S-containing compounds with characteristic odors detected in this experiment are thought to play a positive role in RSCCE during concentration.

• Preventive Nutrition and Food Science
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• v.6 no.2
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• pp.87-90
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• 2001

The volatile flavor components of snow crabs from the Young-duk coast of Korea and their concentrated cooker effluent were isolated by a modified method from Likens and Nickerson, using a simultaneous distillation and extraction apparatus. The concentrated extract was analyzed and identified by gas chromatography and GC-MS. The flavor profile of boiled crab demonstrated that the favorable flavor characteristic of crab involved a seafood-like note, and that of concentrated cooker effluent demonstrated that the weak boiled crab flavor involved a fishy note. The main flavor components of boiled crab were heterocyclic compounds including alkylpyrazines, thizoles and thiolanes, aliphatic ketones including 2-heptanone and nonanone. On the other hand, the main flavor components of cooker effluent were aldehydes including 3-methylbutanal, alipatic ketones including 2-heptanone and alkanes including 2,6,10,14-tetramethyl-pentadecane. Almost all of heterocyclic compounds, which seem to be important contributors to the flavor of boiled crab, were not identified in concentrated cooker effluent. As a result, there may be a need to add the crab flavor components formed through model experiments of Maillard reactions to the concentrated cooker effluent for human consumption.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.670-678
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• 2010

An ecological investigation was conducted in winter from November 2007 to February 2008, around Wangdol Reef in the East Sea to analyze the population structure and fecundity of Chinoecetes opilio. The sex ratio was 30.11:69.89% (female:male) in November, 62.03:37.97% in December, 37.59:62.41% in January and 14.69:85.31% in February. Regression equations indicated highly positive relationships between size and weight parameters (carapace length, width, total weight). During the sampling period ovigerous females were continuously collected. The percentage of ovigerous females was 96% in November, 90.57% in December 89.80% in January, and 88.46% in February. The average number of embryos was 64,800. The regression equation between carapace width and the number of embryos was y = 2.6805x - 0.9182 ($R^2$ = 0.7166). Embryo volume increased as embryo development proceeded. The mean size of an embryo was 0.72 mm. Embryo volume ranged from 0.42 to $0.84\;m^3$ during embryo developmental stages 1 to 3.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.5
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• pp.644-654
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• 2015

This study investigated changes in the quality of fermented red snow crab Chionoecetes japonicus sauce with or without Aspergillus kawachii koji and added salt. Samples were divided into four groups depending on whether koji was added and the amount of salt: RC15, 15% added salt, no koji; RC20, 20% added salt, no koji; RK15, 15% salt plus 10% koji; and RK20, 20% salt plus 10% koji. The samples were fermented at 20±2℃ for 4 months. During the fermentation period, the moisture contents of the four types of sauce decreased while the crude ash and protein contents increased. The pH of the RK groups decreased and was lower than in the RC groups. The acidity of the RK groups increased and was higher than in the RC groups. Both the total nitrogen (TN) and amino nitrogen (AN) levels increased continuously and were higher in the RK groups than in the RC groups. The volatile basic nitrogen (VBN) content increased rapidly and was higher in the RC groups than in the RK groups. The color did not differ significantly among the four groups. The viable cell counts in the four groups increased and no coliforms were detected. The total free amino acid and glutamic acid contents were highest in the RK15 group and the main amino acids in RK15 were aspartic acid, glutamic acid, alanine, leucine, phenylalanine, and lysine. Overall acceptance was significantly higher for the RK groups than the RC groups and RK15 ranked highest among the four sauces. These results suggest that Aspergillus kawachii koji is beneficial for processing fish sauce made using red snow crab.