• Fisheries and Aquatic Sciences
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• v.21 no.6
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• pp.15.1-15.9
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• 2018

Background: Inflammation has been known to associate with many human diseases. The objective of this study was to evaluate an anti-inflammatory effect of ozonated krill (Euphausia superba) oil, which was prepared by the treatment of krill oil using ozone gas. The anti-inflammatory activity was evaluated in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. Results: Ozonated krill oil significantly inhibited nitric oxide (NO) production and suppressed the mRNA and protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in LPS-stimulated RAW 264.7 macrophages. Ozonated krill oil also reduced the mRNA expression of inflammatory cytokines such as interleukin (IL)-$1{\beta}$, IL-6, and tumor necrosis factor (TNF)-${\alpha}$ in LPS-stimulated RAW 264.7 macrophages. To elucidate the mechanism underlying the anti-inflammatory activity of ozonated krill oil, we evaluated the effects of ozonated krill oil on the activation of mitogen-activated protein kinases (MAPKs) pathway. Ozonated krill oil suppressed the LPS-stimulated phosphorylation of p38 MAPK and c-Jun N-terminal kinases (JNK). Conclusion: This study revealed that the ozonated krill oil exhibited an anti-inflammatory effect in LPS-stimulated RAW 264.7 macrophages. To the best of our knowledge, this is the first report that ozonated krill oil suppressed pro-inflammatory mediator and cytokine expression in LPS-stimulated RAW 264.7 macrophages by inhibiting the phosphorylation of p38 MAPK and JNK.

• Journal of Animal Science and Technology
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• v.49 no.5
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• pp.599-610
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• 2007

Effect of dietary krill meal levels on the cellular immunity was studied in broiler chicks activated immune response. One day old male broiler chicks(Ross) were fed the experimental krill meal 0.0(basal), 0.5, 1.0 and 2.0% diets for 3wks. Blood TNF-α activity, ovotransferrin level and Con A induced proliferation of PBMC and splenocytes after 24 hr(21 d age) of the croton oil 10㎕ injection intra- musculary at the age of 20 days compared to the control olive oil. Krill meal diets did not affect growth performance of broiler chicks and plasma ovotransferrin levels but decreased significantly(p<0.0001) TNF-α like activity and proliferation of PBMC relative to krill meal 0.0% diet. And the proliferation of splenocytes were significantly(p<0.05) increased in birds fed krill meal 1.0% diet relative to krill meal 0.5 and 2.0% diets. The croton oil injection induced a significant(p<0.0001) increases in the TNF-α activity or the PBMC proliferation and enhanced circulating ovotransferrin levels relative to the olive oil. In birds injected with the croton oil the proliferation of PBMC was reduced linearly with the increase of dietary krill meal levels, and the proliferation of splenocytes was decreased in the krill meal 1.0 and 2.0% diets relative to olive oil. These results indicated that dietary krill meal changed the innate and cellular immunity in broiler chicks activated by the injection of croton oil.

• Fisheries and Aquatic Sciences
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• v.17 no.2
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• pp.159-165
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• 2014

In this study, Krill Eupausia superba oil was extracted using different solvents and supercritical carbon dioxide (SC-$CO_2$). During SC-$CO_2$ extraction, the pressure was set at 40 MPa and temperatures ranged from $40^{\circ}C$ to $55^{\circ}C$. We examined the differences in volatile compounds and safety profiles among extraction methods. Volatile compounds were determined using the thermal desorption system integrated with gas chromatography-mass spectrometry (GC-MS). Heavy metal content was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). According to our results 10 volatile compounds were identified in krill sample. After SC-$CO_2$ extraction of oil, the concentrations of volatile compounds decreased, but increased after solvent extraction. In krill, heavy metal concentrations remained within the permissible limit. Moreover, Zn and Fe which have health benefits were detected at high concentrations. During a 90 days storage period at different temperatures, microbial activity was found to be lowest in SC-$CO_2$ extracted residues. Thus, the quality of krill oil and the residues obtained using SC-$CO_2$ extraction was higher and the oil was safer than those obtained using conventional solvent extraction. These results can be applied to the food industry to maintain high quality krill products.

• Journal of Animal Environmental Science
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• v.17 no.1
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• pp.33-38
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• 2011

Economic development involves increase in life expectancy as well as human health care. Consequently, demand for fish meal and fish oil is rapidly growing. In particular, Krill (Eupausia superba) oil product is in high demand due to its rich unsaturated-fatty acid, and thus stable supplies are necessary in the krill oil market. It is required for captured krills to be immediately frozen and stored during ship transport, since proteins of the krill are quickly denatured in natural temperature condition. However, the transportation cost has been sharply increased, which encourages researchers to involve in studies for development of efficient oil extraction process. In this study, a solid/liquid separation technique on boat for the krill oil was developed through triple separation tests using only a separator or using either brush or crusher prior to the separator. The separation tests revealed that the efficiency were 46.2, 60.2 and 60.4 % by the separator, combination with brush, and combination with crusher, respectively. In addition, it was found that byproduct, extracted cake, derived from the separation process could be used as a feed stuff. These results suggest that smashing using the brush or crusher prior to the separator is more efficient than using only the separator.

• Analytical Science and Technology
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• v.33 no.6
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• pp.262-273
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• 2020

A fluorine content analysis method for krill oils, which is a representative oil formulation in foods, was developed in compliance with the Korea Food and Drug Ministry's "Guidelines for Validation of Testing Methods Related to Food". Using this method for krill oils, the presence of impurities was evaluated via combustion-ion chromatography (C-IC). A review of published technical data on fluorine in krill oils showed that while the traditional wet potentiometric method was typically used, it was not reliable. Moreover, there was no food testing/analysis laboratory in Korea to perform a fluorine test analysis on such an oil matrix. Therefore, we identified halogen (fluorine) tests, developed to national and international standards, and developed a test method suitable for krill oils by selecting a C-IC method that is sufficiently applicable to the oil matrix. Based on the characteristics of the oil matrix, the optimal test method was established through various experiments by reviewing the concerns related to loss and interference in the preparation and introduction of samples. The fluorine content test was carried out on 11 krill oil products that were purchased online. Most products (with the exception of only one) were found to contain less than the reporting limit obtained by the test method. Furthermore, after additional testing, a high fluorine content of approximately 2,000 ~ 3,000 mg/kg was detected on the krill surface, although the concentration varied depending on the area of the krill. A comparison with samples from two ISO/IEC 17025 testing laboratories confirmed that there was no significant difference in the statistical analysis results obtained by ANOVA among the three laboratories. A testing guide for fluorine content analysis was completed.

• Fisheries and Aquatic Sciences
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• v.17 no.4
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• pp.409-419
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• 2014

The proximate composition and various specific components of Antarctic krill Euphausia superba, in the catch season between March and August were investigated. Frozen krill were freeze-dried and milled. The proximate composition comprised water, proteins, fats, ash, fatty acids, and amino acids, while the specific components were vitamins, minerals, nucleotides, betaine, and astaxanthin. The moisture content of the krill ranged from 77 to 80%, with the highest value in June, and the ash content was between 12 and 13%. The protein content was lowest in May, and the fat content was 18-19%, with the highest value in March. The amino acid content varied according to the season: taurine and glycine were highest in August; ${\beta}$-alanine was higher in April and May; and arginine, ornithine, and lysine were highest in March. The unsaturated fat content was ~50% and omega-3 fatty acids were highest in June. Oil-soluble vitamins A and E were highest in March, and the water-soluble vitamin content was less than that of oil-soluble vitamins. The mineral content was highest in June, and the most abundant mineral was sodium at 235.60 mg/100 g krill. The content of other minerals was lowest (2.94 mg/100 g) in April, except for lead. The nucleotide content was highest in July, while the betaine content was highest in April and lowest in June. The astaxanthin content was highest in May and ranged from 6 to 10 ppm in other months.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2003.11a
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• pp.82-83
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• 2003

To study effect of bean extracts to lessen the growth-suppressing-effect of krill meal diet, dietary krill meal with bean extracts on the performance of broiler chicks and proliferation of splenocytes and peripheral blood mononuclear cells(PBMC) and levels of circulating TNF-$\alpha$ and ovotransferrin in plasma was assayed. The krill meal with bean extracts diet lessened the growth-suppressing effect of the krill meal diet. During acute phase responce, the krill meal with bean extracts diet decreased the proliferation of splenocytes and increased the proliferation of the PBMC and reduced the circulating levels of TNF-$\alpha$ and ovotransferrin in plasma. The results Indicated that the krill meal with bean extracts diet related with the acute phase response in broiler chicks.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.13 no.2
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• pp.65-80
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• 1980

Processing conditions of the krill products such as paste food, krill protein concentrate, seasoned dried krill, powdered seasoning, meat ball, and snack have been examined and the quality was evaluated chemically and organoleptically. In the processing of paste food, krill juice was yielded $71\%$ and krill scrap $29\%$. The yields of paste and broth from the krill juice showed $53\%$ and $43\%$, respectively. In amino acid composition of the krill paste, proline, glutamic acid, aspartic acid, lysine, and leucine were abundant, while histidine, methionine, tyrosine, serine and threonine were poor. The optimum condition for solvent extraction in the processing of krill protein concentrate was the 5 times repetitive extraction using isopropyl alcohol at $80^{\circ}C$ for 5 mins. The yield of krill protein concentrate when used fresh frozen materials was $10.2\%$ in isopropyl alcohol solvent and $8.8\% in ethyl alcohol, and when used preboiled frozen materials, the yield was $13.0\%$ in isopropyl alcohol and $11.8\%$ in ethyl alcohol. Amino acid composition of krill protein concentrate showed a resemblance to that of fresh frozen krill meat. In quality comparison of the seasoned dried krill, hot air dried krill was excellent as raw materials and sun dried krill was slightly inferior to hot air dried krill, but preboiled frozen krill showed the poorest quality. The result of quality evaluation for seasoning made by combination of dried powdered krill, parched powdered sesame, salt, powdered beef extract, monosodium glutamate, powdered red pepper and ground pepper showed that the hot air dried krill was good in color and sundried krill was favorable in flavor. When krill meat ball was prepared using wheat flour, monosodium glutamate and salt as side materials, the quality of the products added up to $52\%$ of krill meat was good and the difference in quality upon the results of the organoleptic test for raw materials was not recognizable between fresh frozen and preboiled frozen krill. In the experiment for determining the proper amount of materials such as dried Powdered krill, $\alpha-starch$, sweet potato starch, sugar, salt, monosodium glutamate, glycine, potassium tartarate, ammonium bicarbonate, and sodium bicarbonate in processing krill snack, sample B(containing $7.7\%$ of dried powdered krill) and sampleC (containing $10.8\%$ of dried powdered krill) showed the most palatable taste from the view point of organoleptic test. Sweet potato starch in testing side materials was good in the comparison of suitability for processing krill snack. Corn starch and kudzu starch were slightly inferior to sweet potato starch, while wheat flour was not proper for processing the snack. In the experiment on frying method, oil frying showed better effect than salt frying and the suitable range of frying temperature was $210-215^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.520-527
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• 2013

This study developed patties using the Antarctic krill Euphausia superba and investigated the food quality of the patties. Three different types of krill patty were produced: krill patties with added 1) corn oil (CKP), 2) AA grade surimi (AKP), and FA grade surimi (FKP). Their proximate composition, Hunter color value, texture, sensory evaluation, and levels of astaxanthin, cholesterol, calories, total amino acids, fatty acids, and fluoride were investigated. The moisture and crude protein contents were highest in FKP. The calorie and astaxanthin contents were highest in CKP and lowest in AKP. The cholesterol content was highest in CKP and lowest in AKP. Measuring the Hunter color value of cross-sections of the patties, the L values were highest for FKP, and the a and b values highest for AKP. The total amino acids were highest in FKP and lowest in CKP. The major fatty acids were highest in FKP. The hardness and chewiness were highest in FKP and lowest in CKP. The fluoride content was highest in AKP and lowest in FKP. The sensory evaluation had the highest scores for FKP and lowest for CKP. Accordingly, FKP appears to have better food quality than the other two products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.201-208
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• 2020

This study examined the anti-obesity effect of krill oil (KO) by regulating adipokines in a high-fat diet (HFD)-induced obese mouse model. The mice were fed a 60 kcal% HFD for 16 weeks, and KO was then administered at an oral dose of 100, 200, and 500 mg/kg/day for four weeks before the end of the experiment. The administration of KO at concentrations of 200 and 500 mg/kg/day decreased body weight gain significantly compared with the HFD-fed control group. In addition, the HFD-fed control group showed the abnormal release of adipokines by an increase in leptin and decrease in adiponectin, compared to the normal diet-fed normal group. On the other hand, KO (500 mg/kg/day)-administered group attenuated the abnormal release of adipokines by the down-regulation of leptin and the up-regulation of adiponectin. Therefore, KO could be a promising therapeutic agent for obesity by the regulation of adipokines.