• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.1
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• pp.37-45
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• 2013

This study was conducted to improve the yield of extracts from Alaska pollock Theragra chalcogramma head and sea tangle Laminaria japonica byproducts using various commercial enzymes, such as Alcalase, Flavourzyme, Neutrase (NH), and Protamex. Among the enzymatic hydrolysates, the yield was highest in hydrolysate incubated with NH for 4 h. NH-treated hydrolysates (NHH) also improved functional properties, such as angiotensin-I converting enzyme (ACE) inhibitory activity and 2,2-diphenyl-1-picryldrazyl (DPPH) radical scavenging activity, as compared to extracts from Alaska pollock head and sea tangle byproducts. Total free amino acid and taste values of NHH were 379.7 mg/100 mL and 24.03, respectively, after digestion for 4 h. These values are 2.2-fold and 1.9-fold higher compared with those of water soluble fractions extracted from Alaska pollock head and non-forming sea tangle, respectively. According to the taste value results, the major taste-active compounds among free amino acids of NHH were glutamic acid and aspartic acid. These results suggest that NHH can be used as an ingredient for natural seasoning preparation.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.6
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• pp.1231-1244
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• 2014

Oysters, especially are excellent source of several mineral including iron, zinc and selenium, which are often low in the mordern diet. They are also an excellent source of glycogen, vitamin B12 and considered the healthiest when eaten raw on the half shell in good tasted season from November to March. This study was investigated for the purpose of obtaining basic data which can be applied to processing of two kinds of canned boiled oyster (canned boiled oyster, canned boiled oyster in bamboo salt). Shucked oyster meat was cooked in steam (15min) after washing with water, filled 90g into can (301-3), added with salt solution and then precooked for 10 min. at $100^{\circ}C$. Canned boiled oyster was added 1.5% salt solution 60mL. Canned boiled oyster in bamboo salt was added 0.5% salt solution 30mL and 0.7% bamboo salt solution 30mL. The cans were seamed using a vacuum seamer, and then sterilized for various Fo values (Fo 8~12 min.) in a steam system retort at $116^{\circ}C$, $118^{\circ}C$. Viable bacterial count, proximate composition, pH, salinity, yield, VBN, amino-N, TBA, mineral, color value, free amino acid, hardness and sensory evaluation of two kinds of canned boiled oyster produced at various sterilization condition (Fo 8~12 min.) were measured after divide to meat and juice. The results showed that canned boiled oyster in bamboo salt sterilized at Fo 8 min. was the most desirable because this condition is the most economical and tasty.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.6
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• pp.851-860
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• 2020

Shrimp in seasoned soy sauce (S-SS) is a popular seafood product in Korea, but it could be potentially hazardous; thus, this study was conducted to investigate its safety. Commercial S-SS were collected and analyzed for pH, volatile basic nitrogen (VBN), hygenic indicator microorganisms (viable cell count, coliforms, and Escherichia coli), food poisoning bacteria (Staphylococcus aureus, Vibrio parahaemolyticus, and Listeria monocytogenes), preservatives (dehydroacetic acid, sorbic acid, benzoic acid, and its salt, parahydroxybenzoate), tar colorants, and sensory properties. Domestic and foreign standards were also investigated for S-SS. Commercial S-SS ranged from to 6.2-7.3 for pH, 13.7-39.1 mg/100 g for VBN, and 4.6-6.9 log CFU/g for viable cells. The coliforms and E. coli of commercial S-SS were from ND to 3.4 log CFU/g and negative, respectively. Food poisoning bacteria, preservatives, and tar colorants were not detected in commercial S-SS. Only the coliform count and presence of E. coli in commercial S-SS exceeded the set standards of vietnam, while all items were within domestic and foreign standards.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.494-504
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• 2023

Sik-hae is a traditional and well-liked salt-fermented seafood with a low salt concentration in Korea. However, it is challenging to find data on market degradation. This study was conducted to investigate sensual characteristics, such as taste, odor and color, of 10 types of commercial Sik-haes [flounder (5 type), Alaska pollock (2 type), black edged sculpin, anchovy, and sandfish] as basic data for developing new products. The salinities of the commercial Sik-haes were significantly difference in the range of 3.0-6.7%. The pH and total acidity of 10 types of commercial Sik-haes were 4.45-5.24 and 0.84-1.46 g/100 g, respectively. The amino acid nitrogen and free amino acid contents, and total taste value were 72.0-333.0 mg/100 g, 425.6-1,726.4 mg/100 g and 17.0-115.9, respectively. According to the taste value, the major taste-related amino acids were aspartic acid and glutamic acid. Volatile basic nitrogen content and Hunter redness value of commercial Sik-haes were 24.5-80.9 mg/100 g and 10.9-28.5, respectively. However, food-grade additives, such as citric acid and monosodium, are occasionally used in commercial Sik-haes to achieve a lower pH or enhance flavor and aroma.

• Fisheries and Aquatic Sciences
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• v.12 no.2
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• pp.79-85
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• 2009

Gelatin hydrolysates with a high inhibitory activity against angiotensin I-converting enzyme (ACE) were fractionated from Alaska pollock surimi refiner discharge. The ACE-inhibitory activity, expressed as $IC_{50}$ (mg/mL), was highest (0.49 mg/mL) in gelatin hydrolysates formed by sequential 2-hr treatments of Pronase and Flavourzyme. After fractionation through four different membrane filters with molecular weight cut-offs of 3, 5, 10, and 30 kDa, the highest ACE-inhibitory activity (0.21 mg/mL) was observed with the 3-kDa filtrate.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.4
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• pp.335-342
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• 2017

Oysters Crassostrea gigas are a globally popular shellfish for human consumption. As filter-feeding bivalve mollusks, oysters may harbor many microorganisms and chemicals that could pose potential human health risks. The objective of this study was to investigate the suitability of cultured oysters for raw consumption or use in seafood products by measuring concentrations of harmful microorganisms and chemicals in their flesh. Microbial concentrations in cultured oysters were found to be: $1.0{\times}10^2-6.0{\times}10^4CFU/g$ (viable cell counts), not detected $(ND)-5.4{\times}10^3CFU/g$ (coliform bacteria), $ND-1.3{\times}10^2CFU/g$ (E. coli), and $ND-4.6{\times}10^3CFU/g$ (Vibrio parahaemolyticus). Other pathogenic bacteria, including Enterohemorrhagic E. coli (EHEC), Listeria monocytogenes, Staphylococcus aureus, and Salmonella spp., were not detected in any samples. Heavy metal concentrations of cultured oysters were ND-0.239 mg/kg (total mercury), ND-1.091 mg/kg (lead), ND-0.968 mg/kg (cadmium). The concentrations of benzo(a)pyrene ranged from $0.280-0.880{\mu}g/kg$. Paralytic shellfish poison ranged from ND-0.58 mg/kg, while diarrhetic shellfish poison was not detected. No radioactivity was detected. These results suggest that oysters intended for raw consumption or use in seafood products should be subjected to chemical and biological controls.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.31-36
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• 2011

This study developed a normal temperature-circulatable retort-sterilized crab analog (RSCA) with a long shelf-life by retort sterilization. We examined the optimum sterilization conditions and quality characteristics of the RSCA. A central composite design for response surface methodology (RSM) was adopted to optimize of the retort sterilization. The central composite design consisted of 11 samples: four factorial points, four star points, and three central points. The sterilization temperature and $F_0$-value for retort sterilization were the independent variables, and the shearing force, whiteness, and sensory score for texture were the dependent variable. The RSM analysis of the multiple response optimization for the RSCA using the Minitap statistical programing gave an $F_0$-value of 3.3 min. at $117.5^{\circ}C$. The RSM analysis also indicated that the sterilization temperature during retort sterilization was the most influential factor, while the $F_0$-value had little effect on the quality of the RSCA. The moisture, pH and volatile basic nitrogen contents of the RSCA product were 73.1%, 7.3 and 17.2 mg/100 g, respectively, and viable cells count was >18 CFU/g. And sensory quality characteristics of this RSCA was similar to those of a commercial crab analog.

• 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.

• Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.163-170
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• 2009

This study was conducted to obtain the gelatin fraction with a high anti oxidative activity from Alaska pollock surimi by-products using a two-step enzymatic hydrolysis and ultrafiltration. Among gelatin hydrolysates from refiner discharge of Alaska Pollock surimi, the highest antioxidative activity (81.5%) resulted from gelatin hydrolysate sequentially treated with Pronase E and Flavourzyme each for 2 hr. However, no difference was seen in the anti oxidative activity of the second hydrolysate (Pronase E-/Flavourzyme-treated hydrolysate) when compared to the permeate fractionated through a 10-kDa membrane. The results suggest that the Pronase E-/Flavourzyme-treated hydrolysate from refiner discharge gelatin of Alaska pollock surimi can be used as a supplementary raw material for improving health functionality.

• Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.181-187
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• 2014

This study was performed to identify the optimum fractionation method and conditions to obtain exopeptidase-active fractions from octopus hepatopancreas (HP) crude extracts (CEs) using four techniques: solid ammonium sulfate fractionation, polyethylene glycol (PEG) fractionation, anion exchange chromatography, and gel filtration chromatography. The fractions with the highest total activity toward L-leucine-p-nitroanilide (Leu-pNA) were fraction IV from the ammonium sulfate and PEG fractionation, and fraction II in ion exchange and gel filtration chromatography. The total exoprotease activity of these fractions was highest in fraction IV (4,050.20 U) of ammonium sulfate fractionation, followed by fraction II (3,600.28 U) from gel filtration chromatography, fraction IV (2,861.30 U) from PEG fractionation, and fraction II (2,576.28 U) from ion exchange chromatography. These results suggest that ammonium sulfate fractionation using 60-80% ammonium sulfate was the most efficient method for separating the exoprotease active fractions from CEs of octopus HP.