• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.394-399
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• 1991

The strain OK-63 isolated from katsuobushi was cultured on wheat bran medium and the isolate was morphologically identified as an Aspergillus niger group and showed maximum pretense activity and multiplication after 6 days of cultivation. Protease was purified by ammonium sulfate fractionation. Sephadex G-100 gel filtration and DEAE-cellulose column chromatography. The purified enzyme showed single band by polyacrylamide gel electrophoresis and the purity was 150 times higer than crude enzyme. The recovery of enzyme activity was found to be 45%.

• Journal of Marine Bioscience and Biotechnology
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• v.7 no.1
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• pp.19-27
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• 2015

The objective of the current study was to evaluate the inhibitory and antioxidant activities of powdered katsuobushi (dried bonito) protein hydrolysates and their corresponding fractions. The powdered katsuobushi (dried bonito) hydrolysates were obtained by enzymatic hydrolysis using Alcalase, ${\alpha}$-chymotrypsin, Neutrase, pepsin, papain, and trypsin. The antioxidant efficacy of the respective hydrolysates were evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, superoxide, and alkyl radical-scavenging activities. Among the hydrolysates, the peptic-derived hydrolysate exhibited the highest antioxidant activity compared to other enzymatic hydrolysates. Therefore, the peptic-derived hydrolysate was further analyzed, and was found to contain an active peptide with an amino acid sequence identified as Pro-Met-Pro-Leu-Asn-Ser-Cys (756 Da). The purified peptides from powdered katsuobushi (dried bonito) had an $EC_{50}$ value of $105.82{\mu}M$, and exhibited an inhibitory effect against DNA oxidation induced by hydroxyl radicals. Taken together, these results suggests that powdered katsuobushi (dried bonito) could be used as a natural antioxidant in functional foods and prevent oxidation reactions in food processing.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.4
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• pp.431-436
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• 2022

For the safety assessment of microbiological and chemical hazards in katsuobushi, fifteen samples of katsuobushi were purchased from supermarkets. The contamination levels of total viable bacteria, coliforms, Escherichia coli, and nine pathogenic bacteria [Staphylococcus aureus, Salmonella spp., Listeria monocytogenes, Bacillus cereus, Vibrio parahaemolyticus, Clostridium perfringens, Enterohemorrhagic E. coli (EHEC), Yersinia enterocolitica and Campylobacter jejuni/coli] were quantitatively or qualitatively assessed. Additionally, the heavy metals (total and methyl mercury) content, radioactivity (¹³¹ I, ¹³⁴ Cs⁺ and ¹³⁷ Cs) were quantitatively assessed. Microbial and chemical analyses were performed using standard methods in Korean food code. The contamination level of total viable bacteria was 2.70 (1.18-4.42) log CFU/g. Coliforms, E. coli and S. aureus were not detected in any samples. Other eight pathogenic bacteria were negative in all samples. The contamination levels of total and methyl mercury were 0.366 (0.227-0.481) and 0.120 (0.002-0.241) mg/kg, respectively. In addition, radioactivity was not detected in any samples. The results will be helpful in revitalizing domestic use and boosting exports of katsuobushi because the microbiological and chemical safety of katsuobushi has been assured. Furthermore, the results may be used as a basis for performing chemical and microbial risk assessments of katsuobushi.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.5
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• pp.228-232
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• 1989

Katsuobushi has widely been used from olden times to prepare soup stock. This study was carried out to prepare stock of powdered Katsuobushi, and to examine the extractive conditions and the contribution of principal taste compounds to its characteristic taste. The extractive condition of powdered Katsuobushi in preparing stock was the most appropriate at $100^{\circ}C$ for 1 minute boiling water-steeping method in flavor, clearance of stock. From the chemical analysis and omission test, the principal taste-active components in $4\%$ solution powdered Katsuobushi under this extractive condition were nucleotides 93.6mg/100ml, free amino acids and imidazole dipeptides 41.3mg/100ml, and non-volatile organic acids 39.3mg/100l1 in order. IMP, inosine, AMP, histidine, anserine, taurine, carnosine and lactic acid were predominant among the detected compounds.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.400-404
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• 1991

Protease was purified from Aspergillus niger propagated on katsuobushi. The optimal pH and temperature of the enzyme were 7.2 and $45^{\circ}C$, respectively. The enzyme was stable at $pH\;5{\sim}8$ and at below $40^{\circ}C$. Enzyme activity was promoted by $K^{-}\;and\;Fe^{2+}$, whereas it was inhibited by $Hg^{2},\;Zn^{2},\;Mn^{2}\;and\;Cd^{2}$. The acidic, basic and neutral amino acid compositions were found to be 22.63, 13.57 and 63.80%, respectively. The content of nonpolar, poler and sulfur-containing amino acids were 39.72, 20.03 and 9.53% respectively, and aspartic and glutamic acids were abundant. The molecular weight was 42,000 and isoelectric point was estimated pH 5.6.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.3
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• pp.209-223
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• 2019

This study was conducted to investigate nutrition characteristics of the following major commercially available dried fish (MCDF) in South Korea: plain-dried fish [nogari (PD-N), Alaska pollock (PD-AP), red tongue sole (PD-RTS), and young tidepool gunnel (PD-YTG)], salt-dried fish [(yellow corvina (SD-YC) and red tilefish (SD-RT)], four types of boiled-dried anchovy of different sizes (BD-As), and freeze-dried fish [Pacific saury (FD-PS), Alaska pollock (FD-AP), and Katsuobushi]. The energy content of the MCDF ranged from 103.0 to 420.5 kcal per 100 g. The MCDF in nutritional and functional properties of minerals were SD-RT and Katsuobushi in calcium; none in phosphorus, sodium, or zinc; Katsuobushi in potassium and magnesium; PD-AP, SD-YC, and SD-RT in iron, PD-AP, PD-RTS, SD-YC, and SD-RT in copper; and PD-N, PD-AP, PD-RTS, SD-YC, SD-RT, FD-PS, FD-AP and Katsuobushi in manganese. The total amino acid content of the MCDF ranged from 15.85 to 71.96 g per 100 g; the major amino acids were glutamic acid, aspartic acid, lysine, and leucine. The fatty acid content of the MCDF ranged from 0.81 to 2.93 g per 100 g. The MCFSP expected in nutritional and functional properties of vitamins were PD-N, PD-RTS, FD-PS, FD-AP, and Katsuobushi in riboflavin; PD-N, PD-AP, PD-YTG, BD-As, FD-PS, FD-AP, and Katsuobushi in niacin; PD-N, PD-RTS, SD-YC, and BD-As in vitamin A; and PD-AP, PD-YTG, SD-YC, and FD-AP in vitamin E.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.1
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• pp.19-24
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• 1989

Changes in lipid components of powdered Katsuobushi during processing such as boiling, smoke-drying were examined. The total lipid (TL) in raw skipkack was $1.8\%$ and it consisted of $79.2\%$ neutral lipid (NL), $7.8\%$ glycolipid (GL) and $12.5\%$ phospholipid (PL), while powdered Katsuobushi product showed $4.5\%$ TL which consisted of $82.5\%$ NL, $9.2\%$ GL and $8.3\%$ PL. The contents of triglyceride, digalactosyl diglyceride, phosphatidyl choline and phosphatidyl ethanolamine decreased when free fatty acid, diglyceride and monogalactosyl diglyceride increased during processing. Also formation of Iysophosphatidyl choline was identified in PL of product. Total fatty acid contents of raw fishes, boiled sample, 1st smoked sample and powdered Katsuobushi were 721.8mg, 589.8mg, 549.6mg and 473.1mg expressed in $C_{23:0}$ as the equivalents of fatty acid contents. Most fatty acid contents of TL revealed a tendency to decrease during processing, there were about $43\%$ decrease in polyenes, $36\%$ decrease in monoenes, and $26\%$ decrease in saturates quantitatively. The major fatty acids in TL, NL, GL and PL of samples were generally $C_{16:0},\;C_{18:0},\;C_{16:1},\;C_{18:1},\;C_{20:5}$ and $C_{22:6}$.

• Food Science and Preservation
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• v.30 no.1
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• pp.146-154
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• 2023

To develop a multi-functional ingredient, the bioconversion of katsuobushi protein was optimized using Bacillus subtilis HA and Lactobacillus plantarum KS2020. The Dendropanax morbiferus extract (DME) culture with protease activity (102 unit/mL) was prepared by B. subtilis with 2% glucose and 1% skim milk through one day of alkaline fermentation. Katsuobushi protein was effectively hydrolyzed by the DME culture at 60℃ for 3 hours, resulting in a tyrosine content of 156.85 mg%. Subsequently, a second lactic acid fermentation was carried out with 10% monosodium glutamate (MSG) using L. plantarum KS2020 to produce higher levels of GABA. Following co-cultivation for three days, DME exhibited a pH of 8.3 (0% acidity). After seven days, the viable cell count of L. plantarum increased to 9.33 CFU/mL, but viable Bacillus cells were not detected. Taken together, a multi-functional ingredient with enriched GABA, peptides, probiotics, and umami flavor was developed through lactic acid fermentation using hydrolyzed katsuobushi protein. These results indicate that katsuobushi protein could be used as a byproduct to produce a palatable protein hydrolysate using alkaline-fermented DME culture as a proteolytic enzyme source.

• Korean Journal of Food Science and Technology
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• v.49 no.2
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• pp.162-167
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• 2017

A Katsuobushi smoking machine was developed and evaluated to determine its benzo(a)pyrene reducing effect. The machine was equipped with two heaters for smoking and chamber heating. The smoke-generating system was equipped with a cadmium sulfide (CdS) smoke sensor, an on/off controller, and a rotating feeder with a smoke inlet. Raw bonito was steamed and then smoked under three smoke levels. After smoking at $45^{\circ}C$ for 108 h, the benzo(a)pyrene concentrations were 5.87, 7.83, and $11.41{\mu}g/kg$ at the low, middle, and high smoke levels, respectively. The benzo(a)pyrene concentrations after low-level smoking at 45, 65, and $85^{\circ}C$ for 108 h were 5.87, 4.82, and $3.27{\mu}g/kg$, respectively. Accordingly, the optimal conditions for benzo(a)pyrene reduction were a lower smoke level and higher smoking temperature. These optimal smoking conditions can be implemented with the newly developed machine, but is not possible using a conventional Katsuobushi smoking machine.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.4
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• pp.169-176
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• 1989

Volatile flavor components in powdered Katsuobushi were simultaneous trapped by steam distillation-extraction method, and these were fractionated into the neutral, the phenolic, the acidic and the basic fraction. Volatile flavor components in these fraction were analyzed by the high-resolution GC and GC-MS equipped with a fused silica capillary column. The whole steam volatile concentrate consisted of $48\%$ neutral fraction(NF), $35\%$ phenolic fraction(PF), $12\%$ acidic fraction(AF) and $5\%$ basic fraction(BF). Thirty components such as 8 hydrocarbons, 8 aldehydes, 6 furans, 5 alcohols and 3 ketones were identified from NF. And sixteen components such as phenol, guaiacol, dimethoxy phenol, eugenol in PF, twelve components such as propionic, butanoic, isopentanoic, n-hexanoic, heptanoic, octanoic acid in AF, ten components such as 2,6-dimethylpyrazine, 2-nethylpyridine, 2,4-dimethylthiaBole in BF were identified. NF and PF gave a much higher yield than others and were assumed to be indispensable for the reproduction of aroma of powdered Katsuobushi. It was also identified eight components of volatile carbonyl compounds such as ethanal, propanal, butanal, pentanal by 2,4-DNPH method.