• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.312-320
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• 1993

Low-salted and fermented squid products, squid jeotkal was prepared and fermented at $10^{\circ}C$. During fermentation of squid, microbiological and chemical changes were examined. Sensory evaluation was also carried out. After 20 days of fermentation, taste and flavor of the squid jeotkal containing $10\%$ NaCl were proven to be the best; in contrast, the jeotkal with $7\%$ NaCl exhibited the highest sensory score. At the period showing the best flavor and taste, viable cell count reached to $10^8/g$. Throughout the fermentation period, types of microorganisms isolated were significantly different in squid jeotkal of different salinity. In general, protease producer and bacteria producing components of jeotkal-flavor and organic acids more likely contributed to producing the jeotkal of the best quality. pH of the squid jeotkal with $10\%$ salinity maintained under pH 7.0 throughout the fermentation periods; however, in the case of the jeotkal with $7\%$ salinity, pH increased over pH 7.0 after day 25. Similar tendency was observed in the results from VBN and hypoxanthine formation. Total nitrogen was decreased as fermentation proceeded; in contrast, total free amino acids were increased.

• Journal of Food Hygiene and Safety
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• v.15 no.1
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• pp.18-24
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• 2000

In this study, ohmic heating was applied for pasteurization of red pepper pow-der, and investigated its pasteurization effect. After pasteurization, seasoned squid-jeotkal was manufactured by using red pepper powder, and its quality changes were investigated. On com-paring sensory evaluation in squid-jeotkal by pasteurized and conventional red pepper powder during storage at 5, 16 and $25^{\circ}C$, quality changes in squid-jeotkal by the pasteurized red pepper powder. But quality change difference between two products were decrease with increasing stor-age temperature. Viable cell counts in two products stored at 5$^{\circ}C$ were increased slowly until 60 days. Viable cell counts in squid-jeotkal by conventional red pepper powder were increased up to ca. 10$^{8}$ CFU/g at 15, 25 $^{\circ}C$ after 30, 15 days, respectively, but that by pasteurized were ca. 10$^{8}$ CFU/g at $25^{\circ}C$ after 30 days. Changes in pH, VBN and NH$_2$-N in two products were shown difference significantly, but were decreased by increasing storage temperature. In squid-jeotkal by conventional red pepper powder, the main free amino acids were glutamic acid, leucine, glycine, aspartic acid and alanine, and these amino acids held 47.95% of the total free amino acid. But in squid-jeotkal by pasteurized red pepper powder, glutamic acid, glycine, aspartic acid, leucine and Iysine, and these amino acids held 57.58% of the total free amino acids.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.2
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• pp.261-267
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• 1995

Low-salted and fermented squid product, squid jeotkal was prepared with the addition of 10% salt and fermented for 50 day at 1$0^{\circ}C$. During fementation of squid, sensory evaluation and changes of volatile components were examined. Volatile flavor components in raw squid and low-salted squid jeotkal were extracted using a rotary evaporating system. The volatile concentrates were identified by GC and GC-MS. Major volatile components of raw squid were methional and 2-methyl-2-propanol. However, alcohols such as propanol, isoamyl alcohol, methionol and phenylethyl alcohol increased during the period of fermentation. The model reaction using microorganism was carried out, in order to confirm formation mechanism ofvolatile flavor compounds of the squid during fermentation. The main volatile components of Pseudomonas sp. D2 model system were isoamyl alcohol and acetoin. Those of Staphylococcus xylosus model system were isoamyl alcohol and phenylacetaldehyde.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.1050-1056
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• 1999

The effect of ${\gamma}-irradiation$ was investigated on salted and fermented squid, squid jeotkal. Squid jeotkal was prepared with salt concentrations of 5%, 10% and 20% and was fermented at $15^{\circ}C$ and $25^{\circ}C$ after ${\gamma}-irradiation$ with doses of 0, 2.5, 5 and 10 kGy, respectively. Proximate composition, salinity, water activity (Aw), pH, total bacteria and sensory evaluation were examined during fermentation periods. Results showed that ${\gamma}-irradiation$ had no effect on proximate composition, salinity and Aw compared with non-irradiated squid jeotkal. However, pH and total bacteria, as well as sensory evaluation, were changed variously with processing conditions such as NaCl concentration, irradiation dose and fermentation temperature. The results of total bacteria and sensory evaluation showed that squid jeotkal with NaCl concentration of 10% and an irradiation dose of 10 kGy maintained high quality for 30 days at $15^{\circ}C$. Therefore, it was considered that ${\gamma}-irradiation$ was effective in processing low-salted squid jeotkal and extending its shelf-life without adding any food additives.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.4
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• pp.636-641
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• 1995

Proteolytic activities were compared using three species involving in squid jeotkal fermentation and showing positive reaction upon casein test : Pseudomonas D2, Flavovacterium odoratum and Acinetobacter calcoaceticus. Pseudomonas D2 produced highest activity of protease at 72h when incubated in our own modified medium(polypeptone, 0.5% ; tryptone, 0.5% ; NaCl, 3% ; pH, 7.5). Thus, this specie was selected for the further study. The growth pattern was coincided with the production of protease. Thus purification of protease was proceeded by ethanol precipitation, sephadex G-100 gel filtration, and DEAE sepharose ion exchange chromatography. The purified protease showed highest activity at pH 7.0 and 5$0^{\circ}C$. The enzyme was very stable over the wide ragnes of the temperature ; even with one hour heat treatment at 7$0^{\circ}C$, the enzyme showed substantial amount of the activity toward casein. In addition, the enzyme was stable over the wide range of pH. Molecular weight of the protease was determined to be 17.4 kD by SDS-PAGE.

• Korean Journal of Agricultural Science
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• v.35 no.2
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• pp.155-165
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• 2008

A seasoned squid Jeotkal, Korean traditional fermented seafood, and its ingredients for manufacturing, including red hot pepper powder, ground garlic, sesame seeds, were irradiated with 0, 0.5, 1, 2, and 5 kGy by electron beam and stored at $4^{\circ}C$ for 4 weeks to determine the changes in microbiological and sensory characteristics. The initial contamination of squid Jeotkal such as total aerobic bacteria, yeast & mold, and coliform bacteria were at the levels of 2.88, 3.04, and 4.20 log CFU/g, respectively. However, electron beam irradiation with does at 5 kGy reduced the total aerobic bacteria to about 1 log CFU/g. Yeast & mold and coliform bacteria were reduced to 1-2 log CFU/g after 2 kGy of irradiation and reached to undetected level when the sample was irradiated at 5 kGy and following storage at $4^{\circ}C$ for 4 weeks. Sensory characteristics showed that electron beam irradiation of up to 5 kGy did not adversely affect overall acceptability of squid Jeotkal and its ingredients during cold storage. Therefore, electron beam irradiation is one of the possible means to improve storage stability of seasoned squid jeotkal, which has limited alternative sterilization methods due to the temperature characteristics of the products.

• Korean Journal of Food Science and Technology
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• v.34 no.4
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• pp.652-660
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• 2002

To develop natural food preservatives for extending the shelf-life of jeotkal (salted and fermented seafood), antimicrobial substances were extracted from 32 types of medicinal herbs and edible plants using 95% ethanol. Among the extracts, Glycyrrhizae radix, Curcumae domestica, Galla rhois, and Resina pini showed relatively high inhibitory effects on the growth of the microorganisms isolated from the deteriorated jeotkal. We selected and tested the extract from Recina pini as a natural jeotkal preservative. This ethanol extract was purified partially by adding equal quantity of water, through which 77% of insoluble materials were removed as impurities. In manufacturing modified jeotkal using squid, sucrose and starch syrup were substituted with sorbitol, $glucono-{\delta}-lactone$ was added instead of vitamin C and lactic acid, and sterilized hot pepper was used instead of natural one. The shelf-life of modified jeotkal was prolonged by 4 days compared with the control jeotkal when stored at $20^{\circ}C$, while that of modified jeotkal containing 1.0% partially purified Recina pini extract was prolonged by 6 days compared to the control. The same tests were conducted for the changran (stomach and intestine of Alaska pollack) jeotkal preservation. The shelf-life of the control jeotkal was 24 days, whereas the modified jeotkal and the Resina pini extract-containing modified jeotkal maintained their qualities without changes in microbial and chemical characteristics for 90 days at $20^{\circ}C$ storage.

• Journal of Food Hygiene and Safety
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• v.15 no.1
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• pp.13-17
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• 2000

The low salt seasoned jeotkal, salted and fermented fisheries product, may has some problems, such as short shelf-life, its putrefaction by mixing some microorganism from additives. It was considered that most microorganism in seasoned jeotkal were introduced from red pepper powder. Therefore, it is important to pasteurize red pepper powder for improving its microbial quality. When red pepper powder was pasteurized by ohmic heating, the survival cell concentration in red pepper powder was reduced to 1-log-unit at 500 V/m, 700 V/m, above 8$0^{\circ}C$. But viable cell counts were reduced from 8.5$\times$10$^{6}$ CFU/g to 2.1 $\times$ 10$^2$CFU/g, i.e. 4.6-log-unit, during ohmic heating at 9$0^{\circ}C$ for 40 min. Color values of red pepper powder during ohmic heating with different holding time were not changed significantly. When squid-jeotkal was manufactured by using the pasteurized red pepper powder, viable cell counts of the product were decreased by about three log cycles, compare with control product. And also the counts of fungi were significantly decreased.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2007.11a
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• pp.213.1-213.1
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• 2007

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1427-1433
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• 1999

The Microbiological, chemical and sensory analyses were carried to evaluate the quality of commercial salted and fermented seafoods and to establish a standardization. The results showed that amino nitrogen(AN) and volatile basic nitrogen(VBN) contents were appropriate in evaluating the quality of shrimp jeotkal. In the range of $150{\sim}300\;mg%\;and\;25{\sim}70\;mg%$, AN and VBN contents were highly correlated to sensory scores, respectively. In the case of squid jeotkal, pH and VBN contents were appropriate to evaluate quality. The coefficients of the correlation between pH and sensory evaluation was 0.84 and the sensory acceptability was high and above pH 6.0. In addition, the coefficients of the correlation between VBN contents and sensory evaluation was 0.95, and the sensory acceptability was high but below 30 mg%. In the case of shell-fish jeotkal, the coefficient of the correlation between VBN content and sensory evaluation was 0.94, and sensory acceptability was high but below 40 mg%.