• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1385-1389
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• 2004

For the development of better Gulbi processing, brine salting method was applied for the Yellow croaker (Larimichthys polyactis). The changes of moisture contents, salt contents, and total microbial numbers in Yellow croaker were measured following different brine concentration (20, 30%), temperature (5, 25, 35$^{\circ}C$), and soaking time (1, 6, 12, 24 hours) by brine salting method. Rate of salt penetration into Yellow croaker muscle increased as higher brine concentration and higher dipping temperature. When compared to commercial products of Gulbi by dry-salting method, the moisture and salt contents in Yellow croaker showed similar values after treated with 20% brine at $25^{\circ}C$ for 1 hour. The weight of Yellow croaker increased about 4% when immersed it in 20% brine at 5$^{\circ}C$ for 24 hours. There was no weight change at $25^{\circ}C$ dipping temperature and reduced 7% of weight at 35$^{\circ}C$ dipping temperature. At 30% brine concentration, the weight of Yellow croaker reduced 1%, 9%, and 13% on weight at 5$^{\circ}C$, $25^{\circ}C$, and 35$^{\circ}C$, respectively. Total microbial counts in Yellow croaker muscle soaked at 30% brine showed 1 log lower numbers than 20%. The muscles had about 1 log higher microbial numbers than the treated brine solution. An ethanol extract of onion peel added to brine for giving better color and for preventing oxidation on Gulbi lipid. The treated group showed higher Land b values on Gulbi surface as well as antioxidant effect on the extracted oil.

• Journal of Food Hygiene and Safety
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• v.14 no.4
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• pp.319-326
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• 1999

Recently, it is continuously rising to concern about the health risk being induced by microorganisms in food such as Escherichia coli O157:H7 and Listeria monocytogenes. Various organizations and regulatory agencies including U.S.FPA, U.S.DA and FAO/WHO are preparing the methodology building to apply microbial quantitative risk assessment to risk-based food safety program. Microbial risks are primarily the result of single exposure and its health impacts are immediate and serious. Therefore, the methodology of risk assessment differs from that of chemical risk assessment. Microbial quantitative risk assessment consists of tow steps; hazard identification, exposure assessment, dose-response assessment and risk characterization. Hazard identification is accomplished by observing and defining the types of adverse health effects in humans associated with exposure to foodborne agents. Epidemiological evidence which links the various disease with the particular exposure route is an important component of this identification. Exposure assessment includes the quantification of microbial exposure regarding the dynamics of microbial growth in food processing, transport, packaging and specific time-temperature conditions at various points from animal production to consumption. Dose-response assessment is the process characterizing dose-response correlation between microbial exposure and disease incidence. Unlike chemical carcinogens, the dose-response assessment for microbial pathogens has not focused on animal models for extrapolation to humans. Risk characterization links the exposure assessment and dose-response assessment and involve uncertainty analysis. The methodology of microbial dose-response assessment is classified as nonthreshold and thresh-old approach. The nonthreshold model have assumption that one organism is capable of producing an infection if it arrives at an appropriate site and organism have independence. Recently, the Exponential, Beta-poission, Gompertz, and Gamma-weibull models are using as nonthreshold model. The Log-normal and Log-logistic models are using as threshold model. The threshold has the assumption that a toxicant is produce by interaction of organisms. In this study, it was reviewed detailed process including risk value using model parameter and microbial exposure dose. Also this study suggested model application methodology in field of exposure assessment using assumed food microbial data(NaCl, water activity, temperature, pH, etc.) and the commercially used Food MicroModel. We recognized that human volunteer data to the healthy man are preferred rather than epidemiological data fur obtaining exact dose-response data. But, the foreign agencies are studying the characterization of correlation between human and animal. For the comparison of differences to the population sensitivity: it must be executed domestic study such as the establishment of dose-response data to the Korean volunteer by each microbial and microbial exposure assessment in food.

• Journal of Food Hygiene and Safety
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• v.22 no.4
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• pp.323-331
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• 2007

This study was designed to estimate self-life of Kimbab and sandwiches marketed in convenience store. While the 12 different type of Kimbab (n=6) and sandwiches (n=6) were kept at $10^{\circ}C$ for 72 hours, quality changes including volatile basic nitrogen, aerobic plate count, pathogens detection and sensorial property was monitored, and effective quality indicators were selected. Volatile basic nitrogen, indicator for protein deterioration was slightly increased during storage periods in all samples. E. coli, Staphylococcus aureus, Salmonella spp. and Vibrio parahaemolyticus were not detected from any of samples. Change of aerobic plate count of Kimbab and sandwiches were increased moderately but increased dramatically after 48 hours of storage. Overall acceptability were maintained over 5, purchasing power limit, for 40 hours in 4 general Kimbab, 48 hours in 2 samgak Kimbab and 42 hours in 2 sandwiches. Shelf-life of each item was calculated from regression equation between reference limit from effective quality indicators, aerobic plate count and sensory property, and storage period. Estimated shelf-lives of general Kimbab were $15{\sim}33$ hours, samgak Kimbab were 32 hours and sandwiches were $27{\sim}30$ hours at $10^{\circ}C$ refrigerated condition.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.27 no.1
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• pp.1-12
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• 1991

An experiment has been carefully designed and performed to verify the theory for the echointergration technique of estimating the density of fish school by the use of steel spheres in a laboratory tank. The spheres used to simulate a fish school were randomly distributed throughout the insonified volume to produce the acoustic echoes similar to those scattered from real fish schools. The backscattered echoes were measured as a function of target density at tow frequencies of 50kHz and 200kHz. Data acquisition, processing and analysis were performed by means of the microcomputer-based sonar-echo processor including a FFT analyzer. Acoustic scattering characteristics of a 36cm mackerel was investigated by measuring fish echoes with frequencies ranging from 47.8kHz to 52.0kHz. The fluctuation of bottom echoes caused by the effects of fish-school attenuation and multiple scattering which occurred in dense aggregations of fishes was also examined by analyzing the echograms of sardine schools obtained by a 50kHz telesounder in the set-net's bagnet, and the echograms obtained by a scientific echo sounder of 50kHz in the East China Sea, respectively. The results obtained can be summarized as follows: 1. The measured and the calculated echo shapes on the steel sphere used to simulate a fish school were in close agreement. 2. The waveform and amplitude of echo signals by a mackerel without swimbladder fluctuated irregularly with the measuring frequency. 3. When a collection of 30 targets/m super(3) lied the shadow region behind another collection of 5 targets/m super(3), the mean losses in echo energy for the 30 targets/m super(3) were about -0.4dB at 50kHz and about -0.2dB at 200kHz, respectively. 4. In the echograms obtained in the East China Sea, the bottom echoes fluctuated remarkably when the dense aggregations of fish appeared between transducer and seabed. Especially, in the case of the echograms of sardine school obtained in a set-net's bagnet, the disappearance of bottom echoes and the lengthening of the echo trace by fish aggregations were observed. Then the mean density of the sardine school was estimated as 36 fish/m super(3). It suggests that when the distribution density of fishes in oceans is greater than this density, the effects of fish-school attenuation and multiple scattering must be taken into account as a possible source of error in fish abundance estimates. 5. The relationship between mean backscattering strength (, dB) and target density ($\rho$, No./m super(3)) were expressed by the equations: =-46.2+13.7 Log($\rho$) at 50kHz and =-43.9+13.4 Log($\rho$) at 200kHz. 6. The difference between the experimentally derived number and the actual number of targets gradually decreased with an increase in the target density and was within 20% when the density was 30 targets/m super(3). From these results, we concluded that when the number of targets in the insonified volume is large, the validity of the echo-integration technique of estimating the density of fish schools could be expected.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.10
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• pp.1510-1516
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• 2015

The objective of this study was to investigate the quality and sensory characteristics of sweet persimmon mashes and spirits fermented by three different yeasts [Saccharomyces species, labeled as LB (Lalvin BM $4{\times}4$), LD (Lalvin DV10), and UC (Uvaferm CM)]. In the production of sweet persimmon wines, UC had the highest alcohol content of 10.20% (v/v) after 9 days of fermentation (P<0.05). The range of pH after fermentation was 3.63~3.75. The total aerobic bacteria and yeast contents increased until day 3 and then continuously decreased to approximately 8.60 log CFU/mL and 8.20 log CFU/mL, respectively. Reducing sugar contents were 3.37% in UC, 3.91% in LD, and 4.05% in LB after fermentation. Total sugar contents were 4.89% in UC, 6.24% in LD, and 5.47% in LB after fermentation. Two-stage single-pot distillation was conducted to produce sweet persimmon spirits. While conducting second distillation, spirits were collected every 100 mL fraction. The alcohol contents gradually decreased as more fractions were collected. The amounts of acetaldehyde were 226 mg/L for LD, 225 mg/L for LB, and 310 mg/L for UC in the first fraction. LD produced the highest volume (677.8 mL) of alcohol in its body part in comparison with LB (408.0 mL) and UC (445.4 mL). In the descriptive analysis, UC had stronger intensities of sweet aroma, sour aroma and taste, and persimmon flavor (P<0.05). Persimmon characteristics seemed to be well characterized by UC. In conclusion, LD was the most efficient in terms of production cost, whereas UC would be used to produce a more flavorful sweet persimmon spirit.

• Food Science and Preservation
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• v.22 no.6
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• pp.920-925
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• 2015

The microbial composition in Nuruk, a Korean cereal fermentation starter, is a critical factor for the quality and organoleptic properties of traditional alcoholic beverages. This study was aimed at monitoring the compositional change and enzyme activity of culturable lactic acid bacteria (LAB) in two types of Nuruk fermented at different temperatures. All culturable LAB were isolated at various time points (0, 3, 6, 10, 20, and 30 days) and identified by 16S rRNA sequencing. In traditional Nuruk type A (TN-A), which was fermented at $36^{\circ}C$, the population of total culturable LAB during the fermentation period was between $10^4$ and $10^5$ log CFU/mL. On the other hand, the LAB population in traditional Nuruk type B (TN-B) fermented at $45^{\circ}C$ (primary fermentation for 10 days) and $35^{\circ}C$ (secondary fermentation for 20 days) was $10^2$ log CFU/mL; however, these bacteria could not be detected after 6 days. Major LAB strains were identified in both Nuruk types: (1) from the MRS-culture of TN-A, Pediococcus pentosaceus at 3-30 days; (2) from MRS-culture of TN-B, P. pentosaceus at 3 days and Enterococcus hirae at 6 days. The protease activities of the dominant LAB isolated from the TN-A and TN-B cultures were within the ranges of 0.64~1.03 mg/mL and 0.74~0.81 mg/mL (tyrosine content), respectively, whereas the ${\alpha}$-amylase activities were 0.75~0.98 mg/mL and 0.78~0.79 mg/mL (amylose content), respectively.

• Food Science and Preservation
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• v.14 no.6
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• pp.571-577
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• 2007

Storage characteristics of fresh and thawed sliced raw fish (flounder and rockfish) washed in different solutions (tap water, A; jade water, B; 0.2% chitosan-ascorbate (CA), C; 0.03 ppm ozone water, D; 1.5% vinegar containing jade water, E; 1.5% vinegar and 0.2% CA containing jade water, F) at $10^{\circ}C$ were investigated. Changes in pH and acidity of thawed sliced raw fish (TS) during storage were lower than for fresh sliced raw fish (DS). The total microbial content (log cfu/g) of A stored for 3 days in DS was 6.7 (which represented an increase of 1 log cycle compared with day zero), but was 5.50 in B, 3.23 in C, 4.90 in D, 2.40 in E and 1.77 in F, the latter similar to counts at day zero. The degree of microbial contamination of DS and TS followed the order F > E > D > C > B > A in flounder, and F > E > C > D > B > A in rockfish. In general the hardness and chewiness of TS was less than for DS. While the effect of CA on TS texture was not significant in flounder, the effect showed in rockfish. For DS, the appearance in B, C and D was relatively good, as was freshness. Fishiness of flavor was in the order A > B > F > E > D > C. Overall acceptability of flounder and rockfish treated with C was better than treatment with the other washing agents. For TS the appearance of flounder and rockfish were good in B and C. The freshness of flounder and rockfish were in the order of D > C > B > A > E > F and D > C > B > A > E > F, respectively. Fishiness of the flavor of sliced raw fish was lowest in D, which also provided the best overall acceptability.

• Korean journal of food and cookery science
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• v.30 no.6
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• pp.663-669
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• 2014

We preprocessed and pickled Deodeok with Doenjang to improve its preservability and to distribute it widely, and we stored Deodeok for 3 weeks at $7^{\circ}C$ and measured its quality. The sample pre-treated with 20% of dextrin retained its early texture better than the samples pre-treated with other methods after 3 weeks of storage (p<0.05). The samples pre-treated with other controls showed propagation of microorganisms; but Doenjang pre-treated with 20% of dextrin or sugar showed less increase in the water content. The microorganisms count in samples pre-treated with other controls was 4.0 log CFU/g after 3 weeks of storage, but the microorganisms count in the sample pre-treated with 20% of dextrin was 2.2 log CFU/g; in other words, the propagation of microorganisms was minimized in the sample pre-treated with 20% of dextrin (p<0.05). In the investigation of the preferences, this D-20 sample showed maximum improvement in color, smell, taste, and other general preferences factors. Thus, the best processing method for the optimal quality maintenance of Deodeok is to sugarize it with 20% of dextrin before pickling with Doenjang. The product prepared using with this process can be preserved for 3 weeks at $37^{\circ}C$; that is, this product is expected to have a refrigerator shelf life of 3 months.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.6A
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• pp.618-627
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• 2002

In processing images using 2 dimensional Discrete Wavelet Transform(2D-DWT), the method to process the pixels around the image boundary may affect the quality of image and the cost to implement in hardware and software. This paper proposed an effective method to treat the boundary pixels, which is apt to implement in hardware and software without losing the quality of the image costly. This method processes the 2-D image as 1-D array so that 2-D DWT is performed by considering the image with the serial-sequential data structure (Serial-Sequential Processing). To show the performance and easiness in implementation of the proposed method, an image compression codec which compresses image and reconstructs it has been implemented and experimented. It included log-scale fried quantizer, but the entropy coder was not implemented. From the experimental results, the proposed method showed the SNR of almost the same SNR(Signal to Noise Ratio) to the Periodic Expansion(PE) method when the compression ratio(excluding entropy coding) of 2:1, 15.3% higher than Symmetric Expansion(SE) method, and 9.3% higher than 0-pixel Padding Expansion(ZPE) method. Also PE method needed 12.99% more memory space than the proposed method. By considering only the compression process, SE and ZPE methods needed additional operations than the proposed one. In hardware implementation, the proposed method in this paper had 5.92% of overall circuit as the control circuit, while SE, PE, and ZPE method has 22%, 21,2%, and 11.9% as the control circuit, respectively. Consequently, the proposed method can be thought more effective in implementing software and hardware without losing any image quality in the usual image processing applications.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.3 no.1
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• pp.27-34
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• 2009

Hearing impaired person's hearing loss has personally various shape, so existing symmetrical auditory filter of frequency band method wasn't properly simulated the hearing impaired person's various hearing loss shape. The shapes of auditory filter are asymmetrical different with each center frequency and each input level. Hearing impaired person which has hearing loss was differently changed with that of normal hearing people and it has different value for speech of quality through auditory filter. In this study, the asymmetrical auditory filter was simulated and then some tests to estimate the filter's performance objectively were performed. The experiment as simulated auditory filter's performance evaluation method used perceptual evaluation of speech quality (PESQ) and log likelihood ratio (LLR) for speech through auditory filter. In the test, processed speech was evaluated objective speech quality and distortion using PESQ and LLR value. When hearing loss processed, PESQ and LLR value have big difference between symmetrical and asymmetrical auditory filter. It means that the difference of the shape auditory filter may affect to speech quality. Especially, when hearing loss existed, auditory filter changing according to asymmetrical shape for each center frequency affected to perceive speech quality of the hearing impaired.