• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.1
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• pp.63-70
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• 1998

The changes of contents of trimethylamine oxide nitrogen (TMAO-N), trimethylamine nitrogen (TMA-N), dimethylamine nitrogen (DMA-N), nitrite nitrogen (nitrite-N), nitrate nitrogen (nitrate-N) and N-nitrosamine (NA) of salt-fermented small shrimp were investigated during fermentation. The contents of TMAO-N decreased, while TMA-N and DMA-N increased during fermentation in all samples. Contents of nitrite-N decreased in the samples supplemented with sodium nitrite during fermentation, whereas the formation of N-nitrosodimethylamine (NDMA) increased. Treatment of ascorbic acid revealed inhibiting effort on NDMA formation compared with the control. The model system was used for the evaluation of ascorbic acid (inhibitor) or thiocyanate (promoter) on the formation of NDMA using salt-fermented small shrimp supplemented with sodium nitrite, The optimum pH for the formation of NDMA was 3.5, and ascorbic acid inhibited the formation of NDMA whereas thiocyanate promoted.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.760-763
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• 2001

Five commercial salt-fermented shrimps contained 29.8~48.3% of salt 3.5%~7.3% of total nitrogen and 0.3~0.7g/100g of amino-nitrogen respectively. The average peptide length(APL) of five commercial salt-fermented shrimps ranged from 10.1 to 15.0. Sample B and E showed longer APL than the others with the values of 15.0 and 14.4 respectively. Protease activity showed the large differences in five samples from 17 unit to 232 unit ; sample C showed the highest protease activity with 232 unit while sample D and E were relatively lower with 17 unit and 18 unit respectively. The chitinase activities which can hydrolyze chitin the one of components on outer layer of shrimp ranged from 14.4 unit to 171 unit. Sample E had the highest chitinase activity as 171 unit but sample B showed the lowest activity with 14.4 unit. Chitooligosaccharides of five commercial salted-fermented shrimps were consisted of monoglucosamine diglucosamine and triglucosamine.

• Korean Journal of Food Science and Technology
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• v.32 no.5
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• pp.1051-1057
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• 2000

Gamma irradiation was applied to develop fermented shrimp product with lower salt concentration, high sensory quality and storage stability. Shrimp was prepared with 15 and 20% of salt and fermented at $15^{\circ}C$. The sample was irradiated for 15% added salt at the 4th week and for 20% at the 6th week during fermentation with 0, 5 and 10 kGy absorbed doses. The irradiation was applied at optimum stage of fermentation determined when the content of amino nitrogen(AN) arrived approximately 400 mg%. Chemical properties such as amino nitrogen(AN), volatile base nitrogen(VBN), trimethylamine(TMA) and neutral protease activity were examined during whole fermentation. The AN, VBN, TMA and protease activity were not affected immediately after gamma irradiation. The more NaCl concentrations and irradiation dose, the less content of chemical compounds and protease activity was found. From the results of chemical properties, it was concluded that fermented shrimp with 15% of salt and irradiated at 10 kGy before optimum fermentation, or 20% and 5 kGy or above were maintained the sound quality during storage compared with the control.

• Journal of Food Hygiene and Safety
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• v.22 no.2
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• pp.105-109
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• 2007

This study monitored and compared the contamination levels of total aerobic bacteria, coliform groups and S. aureus of 16 Shrimp Jeotgal (Salt Fermented Shrimp) products from 3 traditional markets (TM), 3 department stores (DS) and 3 super markets (SM) located on seoul, Korea. Moreover this study was carried out to survey the concentrations of NaCl and heavy metal (lead; Pb) of the Shrimp Jeotgal. The contamination levels of total aerobic bacteria in the Shrimp Jeotgai were $3.35log_{10}CFU/g$ as a mean and $3.71log_{10}CFU/g$ for TM, $3.16log_{10}CFU/g\;for\;DS,\;2.84log_{10}CFU/g$ for SM. The coliform groups were contaminated in 50% of Shrimp Jeotgal and it means that the hygienic control is needed urgently. S. aureus were not detected in every sample. The levels of NaCl were between 17.9 and 28.5%. Heavy metal (lead; Pb) was detected in only 1 product at the level of 0.02 ppm out of 16 products. Although microbiological contamination levels of Shrimp Jeotgal were not much high, hygienic management like HACCP is thought to be needed for the production of Shrimp Jeotgal in traditional market.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.349-355
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• 2000

This study was conducted to enhance the storage stability of fermented shrimp with different salt contents using a high hydrostatic pressure. The effects of the magnitude of pressure and treatment time on the microorganisms of the fermented shrimp were investigated. The highest microbial counts with respect to the salt levels were observed at 18% salt, showing $3.4{\times}10^5\;CFU/g$ for general bacteria, $6.4{\times}10^4\;CFU/g$ for halophilic bacteria, $4.2{\times}10^5\;CFU/g$ for yeast and $3.0{\times}10^4\;CFU/g$ for halophilic yeast. The degree of sterilization increased with the magnitude of pressure and treatment time, and the sterilization could be analyzed by the first order reaction kinetics. The sterilization rate constants $(k_p)$ of the halophilic bacteria was lower than that of general bacteria. The $log(k_p)$ increased linearly with pressure and the slope of the regression line of the halophilic bacteria was greater than that of general bacteria, indicating that the sterilization of the halophilic bacteria was more dependent on the pressure. High hydrostatic pressure treatment was an effective non-thermal sterilization method for the salted and fermented shrimp, and the optimum treatment condition was for 10 min at 6,500 atm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1265-1273
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• 2005

The purpose of this study was to prepare accelerated salt-fermented anchovy sauce using a shrimp processing byproducts (head, shell and tail) as a fermenting accelerator, and to investigate its physicochemical and enzymatic properties. Four types of sauces were prepared with 0, 10, 20, and 30$\%$ (w/w) addition of shrimp byproduct and fermented at 24$\pm$2$^{\circ}C$ for 360 days. During fermentation, all four type sauces decreased moisture content (67.5$\%$68.0$\%$ to 64.0$\∼$64.8$\%$) and pH (5.52$\∼$7.10 to 5.03$\∼$6.58), but showed increase in their crude protein (7.0$\∼$8.2 to 10.8$\%$) and volatile basic nitrogen contents (40$\∼$75 to 180$\∼$200 mg/100 g of sauce). The ratio of amino nitrogen to total nitrogen contents of control (0$\%$) and sauce with 10$\%$ shrimp byproducts (10$\%$ sauce) were maximized at 270 days, whereas 20$ \% $ and 30$\%$ added sauces were at 180 days. Endoprotease and exoprotease activities of anchovy sauces added with 20$\%$ and 30$\%$ of shrimp byproducts tend to be higher than those of control (0$\%$) and 10$\%$ addition. Proteolytic activities of sauces at pH 9 were about 2 times higher than those at pH 6. Amidolytic activities for LeuPNA decreased remarkably during fermentation, and control (0$\%$) almost lost their activity at 180 days, while additional sauces were relatively stable. These suggest that alkaline pretense of anchovy and shrimp byproducts as a endoprotease mainly contributed to the fermentation of salt-fermented sauces. The protein molecular weight distribution of sauces indicated 2 groups of peaks (peak 1,>70,000 da and peak 2, 3,000$\∼$29,000 da). As the fermentation proceeded, peak 1 tended to decrease in all of sauces, but peak 2 increased rapidly from 30 to 270 days. Optimum fermentation periods of control and 10$\%$ sauces were 270 days and those of 20$\%$ and 30$\%$ sauce were 180 days. The results suggest that shrimp byproduct can be used as accelerator of salt-fermented sauce.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.4
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• pp.629-634
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• 2000

The effects of gamma irradiation on changes of chemical compounds of fermented shromp with low salt were studied. The shirmp was salted NaCl concentration of 10%, 15% and 20%, and irradiated at 0, 2.5, 5.0, 7.5 and 10.0kGy. Amino nitrogen (AN), volatile basic nitrogen (VBN), trimethylamine (TMA) and neutral protease acivity were examined during ferentation at 15$^{\circ}C$. A sample with 30% salt concontration was also prepared as a control. The initial contents of AAN, VBN, TMA and protease acitivity were not affected by gamma irradiation. The contents of AN, VBN and TMA were incteased with fermentation period. But, the more increased NaCl concentrations and the higher irradiation dose, the loss increased content of chemical compounds and protease activity were found. Protease was increased until 4~5 weeks and then decreased gradually. The results showed that the chemical compounds and protease activity of salted abd fermeted shrimp prepared with 15% NaCl contentration and 10 kGy irradiation dose, or 20% and 5 kGy or higher were maintained the appropriate level of quality up to 10 weeks of storage compared with the control.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.507-513
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• 2004

Microbiological safety investigation of 36 commercial salt-fermented shrimps revealed presence of coliform and Gram(+) cocci, whereas pathogenic bacteria such as Escherichia coli O26, Salmonella, Shigella, Staphylococcus aureus, Vibrio parahaemolyticus, and V. cholerae were not detected. When pathogenic bacteria were inoculated into 9, 18, and 27% salted shrimps, Salmonella so., E. coli O26, and S. aureus were not detected up to 13, 80, and 90 days of fermentation at $20^{\circ}C$, respectively, whereas up to 15 day in commercial salt-fermented shrimps.

• Journal of the Korean Home Economics Association
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• v.31 no.4
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• pp.193-200
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• 1993

This study was conducted to examine the effects of the level of salted shrimp on the characteristics of kimchi fermented at 2$0^{\circ}C$ for one day and then stored at 4$^{\circ}C$ for 3 or 6 days. The sensory characteristics, pH, total acidity and salt content of kimchi, prepared to have an equal intensity of salty taste, with three levels of salted shrimp and NaCl, were measured. Instron universal testing machine also was used to examine the firmness of kimchi. As the level of salted shrimp and storage periods increased, intensity of translucency, sour odor, carbonic mouthfeel, toughness and sour taste of kimchi increased while firmness and crispness decreased. There was no significant difference in pH among the kimchies. However, total acidity of kimchi increased as the level of salted shrimp increased and the storage period was extended.

• Journal of Food Hygiene and Safety
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• v.17 no.2
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• pp.94-100
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• 2002

This work was performed in order to examine the effect of nitrite, thiocyanate and ascorbic acid on formation of N-nitrosamine(NA) in kimchi, fermented anchovy and shrimp under simulated gastric digestion, in vitro. The contents of nitrate were 10.7~24.5 mg/kg in kimchi, 1.5~5.6 mg/kg in fermented anchovy, 1.0~2.0 mg/kg in fermented shrimp and those of nitrite were average 0.3 mg/kg in all analyzed samples. Dimethylamine and trirmethylarnine contents were 4.9~l5.4 mg/kg, 0.6~0.8 mg/kg in kimchi, 3.3~4.0 mg/kg, 1.9~2.8 mg/kg in fermented anchovy, 30.3~177.9 mg/kg, 4.4~21.3 mg/kg in fermented shrimp, respectively. The contents of N-nitrosodime -thylamine(NDMA) were in the range of 0.8~6.9 $\mu\textrm{g}$/kg in kimchi, 0~l.2 $\mu\textrm{g}$/kg in fermented anchovy and 0~0.9 $\mu\textrm{g}$/kg in fermented shrimp. After simulated gastric digestion, NDMA was increased about 1.5 times in all sample. In every nitrite added samples, the contents of NDMA were increased by 183.1 times in fermented shrimp and were detected 192.4 $\mu\textrm{g}$/kg and 220.9 $\mu\textrm{g}$/kg when it was treated with 4 mM and 8 mM of nitrite, respectively. NDMA, when above samples were added 8 mM nitrite and 6.4 mM thiocyanate, was increased about 1.5 times than control samples. The formation of NDMA was inhibited by 49.9~92.4% in all samples added 12.8 mM ascorbic acid compared with the control sample.