• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.5
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• pp.736-745
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• 2016

Cheonggukjang, a traditional Korean fermented soy food, was prepared by inoculation of Bacillus subtilis EMD4 or Bacillus amyloliquefaciens EMD17 with anti-bacterial or anti-fungal activities into soybeans. Cheonggukjang was also prepared by co-inoculation of EMD4 and EMD17 (1:1, v/v). Control cheonggukjang was prepared by using B. subtilis KACC16450 (Natto strain). Growth of B. cereus cells spiked with starter organisms was completely inhibited by B. amyloliquefaciens EMD17 after 12 h of fermentation at $37^{\circ}C$. Growth of B. cereus was also inhibited by B. subtilis EMD4, but the degree of inhibition was weaker. After 48 h of fermentation, cheonggukjang samples were stored for 10 days at $4^{\circ}C$. B. cereus cells were not detected from cheonggukjang inoculated with EMD4, whereas significant numbers still present in control. The pH values of cheonggukjang samples were not significantly different. During fermentation, cheonggukjang fermented with EMD17 showed the highest fibrinolytic activity and during storage, cheonggukjang fermented with a Natto strain was the highest. Cheonggukjang fermented with a Natto strain also showed the highest amount of total phenolic compounds. The results show that control of B. cereus in cheonggukjang is possible by using starters such as B. amyloliquefaciens EMD17.

• Korean Journal of Food Science and Technology
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• v.38 no.6
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• pp.730-737
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• 2006

High performance liquid chromatographic methods for the simultaneous determination of 12 biogenic amines were developed and contents of biogenic amines in 23 varieties of Korean commercial fermented food were analyzed. Dansyl derivatives of biogenic amine were very stable and had good peak resolution. Except agmatine, the recovery of biogenic amines from soybean paste with extraction of 0.1 N HC1 added biogenic amines to soybean paste was greater 85%. The calibration curve showed good linearity over a concentration range up to 50 ${\mu}g/mL$. In the determination of biogenic amine level in Korean commercial fermented foods, doenjang and chungkukjang (fermented soybean pastes), soy sauce, anchovy and pacific sand lance liquid jeotkal (fermented fish sauce products), and cabbage kimchi had high level biogenic amines. Especially, traditional doenjang had a histamine (HIS) level of 952.0 mg/kg, a tyramine (TYR) level of 1,430.7 mg/kg. Most cheese had low level of biogenic amines, but one Gouda cheese had a tyramine (TYR) level of 97.5 mg/kg. A low level of biogenic amines was detected in wines, beer, yoghurt, and sausage. Putrescine (PUT), cadaverine (CAD), tryptamine (TRY), histamine (HIS), tyramine (TYR), and 2-phenylethylamine (PHE) were mainly formed in fermented foods by the action of microorganism, so their levels were high with a range. On the other hand, spermidine (SPD), spermine(SPM), serotonin (SER), noradrenaline (NOR), and dopamine (DOP) were formed originally via biosynthesis with consequent low level.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.117-124
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• 1984

Sarine scrap usually comprises about $40\%$ of the raw fish in processing. The purpose of this study is to establish the desirable methods for proteinaceous materials from the sardine scrap through autolysis or enzymatic digestion and to convert them into useful by-products such as sardine sauce. Sardine scrap was chopped and mixed with equal weight of water, and be hydrolyzed them by autolysis and/or by addition of commercial proteolytic enzyme and various concentrations of sodium chloride. The optimal conditions for hydrolysis of sardine scrap were revealed in temperature at $55^{\circ}C$ and 4 hours digestion with bromelain($0.4\%$) and commercial complex enzyme ($6.0\%$), and those conditions were also applicated in autolysis. The maximum hydrolyzing rate of protein and released amino nitrogen were $82.5\%,\;5.2\%$ through autolysis, $84.3\%,\;5.8\%$ by bromelain digestion and $92.5\%,\;5.9\%$ by complex enzyme, respectively. In the products prepared from sardine scrap through autolysis or bromelain digestion, hypoxanthine was dominant, as $17.4 {\mu}mole/g$, dry matter for autolysis and $16.0 {\mu}mole/g$, dry matter, for bromelain digestion among the nucleotidcs and their related compounds, respectively. The abundant free amino acids were leucine, glutamic acid, lysnie, valine and alanine. The contents of those amino acids were $51.3\%,\;48.3\%$ of the total free amino acids, respectively. And the contents of 5'-IMP and TMAO were negligible but total creatinine was developed in value from $9.2\%\;to\;10\%$ of total extracted nitrogen. The flavor of sardine sauce prepared from sardine scrap by autolysis or enzyme digestion were not inferior to that of traditional Korean soy sauce by sensory evaluation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.1
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• pp.97-106
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• 1984

The Antarctic krill, Euphausia superba, is drawing attention over the world as the largest source of unutilized proteins in the ocean. For the use of krill as a human food, processing conditions of krill sauce by autolysis and/or commercial proteolytic enzyme digestion were examined. The krill was chopped and mixed with equal weight of water, and hydrolyzed by autolysis and/or commercial proteolytic enzyme digestion. The optimal conditions for hydrolysis of krill were $52.5^{\circ}C$, pH 7.0-7.5, 3 hours by autolysis, $52.5^{\circ}C$, pH 6.3, 3hours by bromelain (0.5 %) digestion, and $52.5^{\circ}C$, pH 7.0-7.5, 3 hours by commercial complex enzyme (5 %) digestion, respectively The maximum hydrolyzing rate of protein were 83.2 % by autolysis, 89.7 % by bromelain digestion, 92.7 % by commercial complex enzyme digestion. After krill meat hydrolyzed by autolysis at optimum condition, inactivated at $100^{\circ}C$ for 20 minutes and filtered with Buchner funnel. Two kinds of products were prepared with krill hydrolysate and preservatives: one contained 10 % of sodium chloride and 0.06 % of benzoic acid and the other 10 % of sodium chloride and 3 % of ethyl alcohol. These products were filled in the sterilized glass bottle and sealed. The pH, volatile basic nitrogen, amino nitrogen, color value (L, a and b values) and viable counts of bacteria were determined during storage at $37^{\circ}C$. The results showed that the products could be preserved in good condition during one month at $37^{\circ}C$. As a method to reduce the sodium level in krill sauce, it is convinced that sodium chloride could be replaced half in partially by potassium chloride. In the products prepared from krill by autolysis, bromelain or commercial complex enzyme digestion, hypoxanthine and 5'-IMP were abundant among the nucleotides and their related compounds as 15.3-20.4 ${\mu}mole/g$, dry solid, 2.2-2.5 ${\mu}mole/g$, dry solid, respectively. The abundant free amino acids were lysine, leucine, proline, alanine and valine. The contents of these amino acids were 67.4 %, 69.4 %, 69.8 % of the total free amino acids of each products. And TMAO, betaine and total creatinine were low in contents. The flavor of krill sauce prepared from krill by autolysis or enzyme digestion was not inferior to that of traditional Kerean soy sauce by sensory evaluation.