• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.191-200
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• 1979

For the use of antarctic krill as a fond protein source its compositional characteristics were investigated as the first part of the work includes other subjects such as processing of drill paste, concentrates, and fermented or seasoned product. In general composition of fresh frozen and preboiled frozen krill on board, the contents of crude fat and free amino nitrogen were higher in the former than in the latter which contained a high amount of ash. VBN was rather high as much as 37.6 and $26.4\;mg\%$ in both fresh frozen and preboiled krill. The pH of drill homogenates was 7.1 to 7.2 in both cases. Such a low pH might be attributed to a long term storage and temperature fluctuations during frequent transshipping. The amino acid competition of fresh frozen krill meat showed relatively high amount of glutamic acid, aspartic acid, lysine, proline, and leucine while methionine, histidine, serine, tyrosine, and phenylalanine were lower. Among the essential amino acids lysine and leucine were higher and methionine was lower. In tile composition of free amino acid proline, lysing, arginine, and alanine were higher comparatively to the contents of histidine, aspartic acid, serine, and threonine. It is noteworthy for nutritional qualification that tile essential amino acids particularly as lysine were abundant similarly to that of fishes. Heavy metal contents of krill meat 0.039 to 0.048 ppm as Hg, 0.06 to 0.11 ppm as Pb, less than 0.32 ppm as Zn, 0.008 to 0.012 ppm as Cd, 0.61 to 0.68 ppm as Fe, 0.87 to 1.37 ppm as Cu, and nondetective as Cr. A high Cu content seems to be resulted by tile blood pigment of crustacea. The ratio,1 of edible portion to non-edible portion were 37:63 in fresh frozen and 42:58 in preboiled frozen krill respectively. Release of drip after thawing was more in fresh frozen than in preboiled frozen drill marking $36\%$ and $24\%$ of both respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.2
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• pp.120-132
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• 1993

A continuous hollow fiber membrane reactor(CHFMR) was developed and optimized for the production of yellowfin sole(Limanda aspera) skin gelatin hydrolysates using trypsin. The results were summerized as follows: The $K_m$ value of the CHFMR was 2.4 times higher than that of the batch reactor, indicating reduced enzyme affinity for the substrate. The $K_2$ value of the CHFMR was 8.5 times lower than that of the batch process, showing a significant reduction in trypsin activity in the CHFMR. The optimum operating conditions for the CHFMR process were $55^{\circ}C$, pH 9.0, flux 7.79 ml/min, residence time 77min, and trypsin to substrate ratio, 0.01(w/w) After operating for 60min under the above conditions, $79\%$ of the total amount of initial gelatin was hydrolysed. Enzyme leakage was observed through the 10,000 MWCO membrane after the 20min of reactor operation, while none occurred after 5hr. Total enzyme leakage was about $12.95\%$ at $55^{\circ}C$ for 5hrs. However, there was no apparent correlation between enzyme leakage and substrate hydrolysis. The membrane has a significant effect on trypsin activity loss for 60min of the CHFMR operation. The CHFMR operating with the membrane lost $34\%$ of the initial activity versus a $23\%$ loss of activity after 3hr in the continuous reactor lacking the hollow fiber membrane. The measurement of fouling property showed that relative flux reduction was $91\%$ and flux recover rate was $92\%$ at $10\%$ substrate solution. The productivity(378.85mg product/mg enzyme) of the CHFMR was more than 4 times higher than that of the batch reactor at $55^{\circ}C$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.4 no.1
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• pp.31-41
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• 1971

The present study was directed to define the degradation pattern of the nucleotides and their related compounds in the muscle of anchovy during drying. Three kinds of samples, fresh, sun dried and boiled-and-dried anchovy, were prepared and the contents of nucleotides and related compounds of samples were determined by ion exchange chromatography. The results obtained are summarized as follows: Almost all of ATP disappeared in both muscle of sun dried and boiled-and-dried anchovy, although the initial content of ATP in fresh muscle was very low ($1.8{\mu}moles/g$, dry basis). But the remainning amount of ADP was considerably high while the other nucleotide almost entirely disappeared. This suggested that the residual ADP is responsible to the 'bound nucleotide' of myofibrils. In general, AMP content was comparatively lower than that of other nucleotides. Among three samples, the boiled-and-dried sample showed relatively higher AMP value than others. The amount of IMP remained in muscle remarkably varied between the boiled-and-dried anchovy and sun dried anchovy, the former's value being sixteen times higher than that of latter. In the contents of inosine and hypoxanthine, the sun dried anchovy marked an exceedingly high value equivalent to 2.7 times of the boiled-and-dried anchovy. In comparison of the ratio of inosine and hypoxanthine, hypoxanthine was accumulating in boiled-and-dried anchovy whereas inosine was in the sun-dried anchovy. Eighty three percent of total nucleotides in the fresh anchovy retained in the boiled-and-dried anchovy and IMP ratio in total nucleotides was $73\%$. On the contrary, the sun dried anchovy showed barely $10\%$ of retention rate and IMP ratio was only $38\%$. Considered from the flavor quality of dried anchovy, so far as concerned IMP content, it may be said that the boiled-and-drying method is more favorable process for dried product of anchovy than the sun-drying method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.21 no.1
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• pp.57-66
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• 1988

As a method of utilization of sardine, the processing conditions of the sardine sauce extracts and the taste compounds of products were investigated. To prepare the sardine sauce extracts, chopped sardine was mixed with $1\%$, onion powder, $1\%$ garlic powder, $1\%$ red pepper powder, loft koji and $50\%$ water, and then hydrolyzed under different conditions of hydrolysis. The optimum conditions for hydrolysis were $55^{\circ}C$, 6 hours, pH 6.5-7.0. After hydrolysis, the hydrolysates were heated at $100^{\circ}C$ for 20 minutes with $5\%$ soybean protein isolate for inactivation of enzymes and improvement of bitter taste of the hydrolysates. Finally, $10\%$ salt was added to develop the characteristic taste of sauce extracts. The major taste compounds of the products were free amino acids, non-volatile organic acids and nucleotides and their related compounds. The major free amino acids in the products were arginine, histidine, lysine, glutamic acid, phenylalanine, leucine and alanine. The contents of these free amino acids were in the range of $68.2\%\;to\;69.9\%$ of the total free amino acids of products. The major non-volatile organic acids ill the products were lactic acid and $\alpha-ketoglutaric$ acid which occupied more than $95\%$ of total non-volatile organic acids. The contents of free amino acids, non-volatile organic acids and nucleotides and their related compounds were not changed during storage. Total creatinine, betaine and TMAO were seemed to act an auxiliary role in taste of the products. Judging from the results of chemical experiments and sensory evaluation, the product prepared with koji and soybean protein isolate was excellent as seasoning materials.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.689-700
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• 1996

Fisheries products have to be produced and maintained by work processes from the environment, sometimes helped by people. In Korean fisheries both environmental production and its economic use are included within the windows of system approach. EMERGY is the sum of all inputs expressed as one form of solar energy required directly and indirectly to make a product. Calculating EMERGY flows into Korean fisheries evaluates the real wealth contributed by environmental production and its economic use. Several indices calculated from EMERGY analysis table and a three-arm diagram give perspective on the type and efficiency of the environmental uses. Net EMERGY yield ratio is a measure of its net contribution to the economy beyond its own operation. For adjacent waters fisheries in Korea, the net contribution to the economy is 11.85 or higher, which is a stimulus to the economy that is able to purchase it. EMERGY investment ratio measures the intensity of the economic development and the loading of the environment. The ratio for Korean fisheries as a whole is 0.50, for the adjacent waters fisheries 0.09 and for the shallow-sea cultures 1.28, which is lower than the same index for the industry of the developed country (7.0). The component of environment drawn into production are large compared to purchased investment in Korean fisheries. Much more EMERGY is contained in fisheries products than in the paid services used to process the products. The EMERGY exchange ratio for Korean fisheries as a whole is 6.98, for the adjacent waters fisheries is 10.69 and for the shallow-sea cultures is 1.25. Using market values to evaluate wealth of environment resources is found to be many times too small. Money is paid only to people for their contribution, and never to the environment for its contribution. Macroeconomic value is the appropriate measure for discussing large-scale considerations of an economy, including environment and human goods & services.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.6
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• pp.529-532
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• 2000

To establish a food safety of dried layer, heat treatment effect on the bacterial density of dried layers was investigated. And a modified process developing experiment for dried layer products using closing type drying oven was carried out. tittle bacterial density difference on the dried layer products were found before and after heat treatment at $90^{\circ}C$ for 6 hrs called Hwaip treatment having been used for long term storage. Direct or indirect heat treatment of dried lavers using gas burner and frying pan reduced about 1 to 3 log cycle of viable cell count from $10^8\;CFU/g\;to\;10^5\;CFU/g$. Heat treatment by direct surface contact type cooking machine being used in the market place for cooked dried layer products could reduce the viable cell count on the layer product from $2.2{\times}10^5{\~}5.2{\times}10^7\;CFU/g\;to\;7.0{\times}10^2{\~}5.0{\times}10^5\;CFU/g$, Ultraviolet irradiation (20 W, 30 cm) to one or both side of the dried laver products reduced the viable cell count from $2.2{\times}10^6\;CFU/g\;to\;8.0{\times}10^5\;CFU/g\;and\;2.0{\times}10^5\;CFU/g$, respectively. The viable cell count of the dried layer products produced by modified process using a closing type dryer was about $10^3\;CFU/g$ and lower 3 log cycle than that in the products collected in market place and made by open type dryer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.22 no.2
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• pp.49-58
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• 1989

For the effective utilization of anchovy as a food source, this work was undertaken the com-parison in food quality of anchovy snacks and its changes during storage at room temperature ($24\pm4^{\circ}C$). Chopped anchovy was mixed with soft flour($340.0\%$, w/w), corn starch($10.0\%$, w/w), sodium chloride($2.5\%$, w/w), monosodium glutamate($0.1\%$, w/w), sodium bicarbonate ($2.5\%$, w/w), water($5.6\%$, w/w), onion powder($0.3\%$, w/w), garlic powder($0.3\%$, w/w), red pepper powder($0.3\%$, w/w) and sodium erythorbate($0.2\%$, w/w), The mixture were rolled, aged, co沇ed, dried and finally parched or deep-fried at $190\pm10^{\circ}C$. The anchovy snacks were packed in the casted polypropylene film bag ($16cm{\times}14cm$), The changes in moisture contents, water activity, pH, volatile basic nitrogen, contents of amino acid and color values of products were negligible during storage. The results of TBA value and peroxide value showed that lipid oxidation can be retarded by adding antioxidant and spices. Judging from contents of amino acid and mineral, the products were more nutritive than the sold shrimp snack on the market. From the results of sensory evaluation and chemical experiments, the product prepared with sodium erythorbate could be preserved in good quality during storage of 120 days.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.5
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• pp.401-408
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• 1985

In order to develop new types of product which can offer a sanitary and preservative duality, and convenience to consumers in marketing and cooking particularly in urban area, two processing methods of ready-to-cook food materials with dark fleshed fishes like sardine and mackerel were investigated. A method applied, in this work, is processing of ready-to-cook sardine meat "surimi" in which sardine meat is treated with alkaline solution to stabilize myofibrillar proteins, washed thoroughly with water to remove soluble components, and added with a proper amount of polyphosphate and sorbitol to enforce the functional property of meat such as water holding capasity, elasticity, and gel strength. The textural properties of fish meat paste made from the "surimi" meat were greatly dependent upon the stability of myofibrillar proteins and the elimination of water soluble components. The salt soluble proteins of sardine meat were so unstable in post-mortem stage that the gel forming ability was lost within 3 days at $5^{\circ}C$ storage and 2 to 3 weeks even at $-20^{\circ}C$ although the freshness was well kept for a week at $5^{\circ}C$ and several months of storage at $-20^{\circ}C$. A proper way of treatment to keep the proteins stable was that fish meat must be washed with $0.4\%$ sodium bicarbonate solution followed by 3 to 4 times washing with water. This resulted in removal of $80\%$ water soluble proteins and 50 to $60\%$ lipids. The addition of polyphosphate and sorbitol affected the stability of proteins during the storage of "surimi" meat. When phosphate and sorbitol were added in the ratio of $0.3\%:\;0.3\%,\;0.6\%:\;3\%,\;0.6\%:\;6\%,\;0:\,0.3\%\;and\;0.3\%:\;0$, the gel forming ability terminated in 35 days, 21 days, 14 days, 14 days, and 14 days of storage at $-30^{\circ}C$, respectively, while that of the control was 7 days. And it was also noteworthy that at least 8.0 mg/g of salt soluble protein nitrogen content was required for gel formation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.4
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• pp.235-240
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• 1979

A study on the amino acid composition of raw frozen krill, and krill solubles manufactured in forms of paste and powder has been carried out. The raw frozen krill was thawed, chopped, mixed and homogenized with same amount of water. The mixture was autolyzed or hydrolyzed by tile addition of $0.2\%$ pronase-p, a commercial proteolytic enzyme, to the weight of the raw frozen krill at $45^{\circ}C$ for 4 hours. After a thermal inactivation of enzymes at $95^{\circ}C$ for 15 minutes, the autolysate and the hydrolysate were centrifuged and filtered through gauzes, respectively, and then tile lipid layer in the supernatant was removed, The autolysate and the hydrolysate were finally concentrated under reduced atmospheric pressure in a rotary vacuum evaporator at $45^{\circ}C$ for 1 hour to produce the krill solubles in form of paste. The powdered krill solubles were prepared by the addition of $5\%$ starch to the autolysate and hydrolysate and by means of concentration in the rotary vacuum evaporator at $45^{\circ}C$ for 30 minutes and a forced air drying at $58^{\circ}C$ for 3 hours with a air velocity of 3m/sec. Among the amino acids in raw frozen krill, glutamic acid, lysine, and aspartic acid showed high values in quantity and then followed leucine, alanine, arginine, glycine and proline. The qnantity of histidine was very small and that of cystine was only in trace. The krill solubles in forms of paste and powder prepared by autolysis and hydrolysis with pronase-p revealed almost the same patterns in amino acid composition as in raw frozen krill. In case of free amino acids, a large quantity of it in raw frozen krill consisted of lysine, arginine, proline, alanine and leucine. The quantities of cystine, histidine and glutamic acid were, in contrast, very small. In the soluble krill paste prepared by autolysis, lysine, leucine, threonine and alanine existed in large quantities among the free amino acids and cystine, aspartic acid and histidine existed in small quantities. The contents of almost all of the free amino acids ill soluble krill paste perpared by hydrolysis with pronase-p were increased slightly as compared with those in soluble krill paste prepared by autolysis. In this product, the contents of cystine, histidine and serine were very low and lysine, leucine, arginine and proline were the dominant group in quantities among the free amino acids. The krill solubles in forms of paste and powder were not inferior to whole egg in the view point of its essential amino acid composition.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.170-174
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• 1999

Proessing conditions for fermented and dried sauces with the underutilized fishes were investigated. Hair tail, gizzard shad, and kangdale were hydrolyzed at $60^{\circ}C$ for 6 hours using $4\%$ Alcalase, and their hydrolysates were separted by molecularporous membrane. The hydrolytic ratios of hair tail, gizzard shad, and kangdale were estimated to be $84.2\%$, $83.6\%$ and $85.1\%$, respectively. Amino nitrogen recoveries were determind to be $73.1\~73.9\%$ by a membrane with molecular weight cutoff 100 dalton and $91.7\~92.5\%$ by a membrane with 500 dalton. Ultrafiltration was very efficient means for removing bitter taste. With the additions of $2\%$ glucose, $4\%$ lactose and $4\%$ skim milk, product yields of hair tail, gizzard shad, and kangdale were determind to be $16.4\%,\;17.2\%$ and $17.0\%$, respectively. Water adsorption rates of hair tail and kangdale showed $5.0\~9.2\%$ and $5.5\~9.6\%$, respectively, under Aw 0.52$\~$0.94. Contents of total nitrogen in the fermented and dried sauces prepared with hair tail, gizzard shad and kangdale were $3.9\%,\;4.1\%$ and $3.7\%$, respectively, and those of amino nitrogen were $3.2\%,\;3.4\%$ and $3.1\%$, respectively. In the fermented and dried sauces prapared with hair tail, gizzard shad and kangdale, the hygroscopities at Aw 0.88 were $6.9\%,\;7.5\%$ and $6.8\%$, respectively, and solubilities under dissolved in water for 30 minutes were $84.6\%,\;83.6\%$ and $93.8\%$, respectively.