• Food Science and Preservation
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• v.23 no.6
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• pp.811-818
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• 2016

The purpose of this study was to investigate changes in the amino acid content and physicochemical properties of Cheonggukjang prepared by using various soybean cultivars (Daewon, Deapung, Seadanbeak, and Taekwang) and a functional microorganism (Bacillus subtilis HJ18-9). These soybeans were conventional Cheonggukjang (control) and Cheonggukjang fermented with Bacillus subtilis HJ18-9 (treated). The moisture contents of steamed, control, and treated soybean were 62.45~67.12%, 63.28~67.14%, and 64.50~66.87%; amino-type nitrogen contents were 6.53~24.25 mg%, 27.63~122.09 mg%, and 37.29~133.48 mg%; and ammonia-type nitrogen contents were 26.92~47.95 mg%, 45.45~156.36 mg%, and 28.02~121.13 mg%, respectively. The umami taste associated with several amino acids (aspartic acid and glutamic acid) in Cheonggukjang was lower than that for steamed soybeans, while the bitter taste from amino acids (methionine, valine, isoleucine, leucine, and phenylalanine) was higher than that for steamed soybeans. The result of sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that the molecular weight of steamed soybeans was less than 100 kDa, while control and treated groups showed low molecular weights below 34 kDa, confirming their protein hydrolysis to small molecular weight. These results are information for developing functional fermented soybean paste and diversification using soybean cultivars.

• Korean Journal of Food Science and Technology
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• v.45 no.6
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• pp.700-707
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• 2013

The purpose of this study was to monitor physicochemical changes of olive flounder (Paralichthys olivaceus) muscle by iced water pre-treatment. Moisture content, crude fat content, nucleotide content, texture (hardness and toughness), and rigor mortis were assessed. The sensory evaluation was performed with a nine-point hedonic test. K-values, a parameter of fish flesh freshness, were also calculated from the content of nucleotides and their corresponding decomposition products. Pre-treatment of flounder flesh with iced water was found to be fresher compared to the control, as determined by a difference in the K-values. Iced water pre-treatment hastened postmortem stiffness, as judged from the rigor index, and increased inosine monophosphate (IMP), which is known to be a savory taste compound, more quickly as adenosine triphosphate (ATP) degradation proceeded.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.6
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• pp.791-798
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• 1998

To develop natural flavoring substances. optimal hydrolysis conditions for two stage enzyme hydrolysates (TSEH) using low-utilized shellfishes such as purplish clam and frozen oyster stored at $-20^{\circ}C$ for 60 days. The optimal conditions for TSEH method were revealed in temperature at $50^{\circ}C$ 3 hours digestion with alcalase (Aroase AP-10, $0.3%$ w/v, pH 8.0) at the 1st stage and $45^{\circ}C$ 2 hours digestion with neutrase (Pandidase NP-2, $0.3\%$ w/v, pH 6.0) at the 2nd stage. Among water extracts, autolytic extracts and 4 kinds of enzyme hydrolysates tests, TSEH method was superior to other methods on the aspect of yields, nitrogen contents, taste such as umami and control of off-flayer formation, and transparency of extracts. From the results of chemical experiments and sensory evaluation, we may conclude that TSEH from low-utilized marine products is more flavorable compared the conventional enzyme hydrolysates, it could be commercialized as the seasoning substances.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1843-1851
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• 2014

This study evaluated the quality characteristics and antioxidant activities of barley Doenjang (soybean paste) containing various contents (4, 12, and 20%) of kelp extracts. After 60 days of fermentation, pH, acidity, and viscosity of Doenjang were 5.80~6.86, 0.57~1.87%, and 4,913.3~9,333.3 cps, respectively, showing significant differences according to content of kelp extracts. Amino-type nitrogen contents was 902.60~921.90 mg%. For color values, L and b values increased significantly (P<0.001), whereas a value decreased slightly according to kelp extracts. DPPH radical scavenging effect ($IC_{50}$) for butylated hydroxyanisole ranged from 10.28 mg/mL to 23.23 mg/mL. DPPH radical scavenging effects of control was highest among the samples. The total polyphenol and flavonoid contents were 12.72~6.37 mg tannic acid equivalence/g, and $0.98{\sim}1.56{\mu}g$ rutin equivalence/g, respectively. Initial counts of total bacteria and lactic acid bacteria were 7.20~7.57 log CFU/g, and 4.20~4.71 log CFU/g respectively, showing significant difference according treatment and fermentation (P<0.05). In the sensory evaluation, 20% kelp extract Doenjang (5.6) showed higher overall acceptability than other samples (6.5) (P<0.01). Especially, umami taste (6.1) and texture (6.4) of 20% kelp extract Doenjang were higher than those of control (P<0.05). These results suggest that Doenjang containing kelp extracts, will be good for industrial fields.

• Korean Journal of Food Science and Technology
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• v.53 no.4
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• pp.375-381
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• 2021

This study investigated the physicochemical properties and chemosensory characteristics of radish samples. Brix results in Matdong-radish showed the highest value (1.5±0.1%), and Mansahyungtong-radish showed the lowest. In terms of salinity, Mansahyungtong-radish had the highest value (1.2±0.1%), and there were no significant differences among samples except Mansahyungtong-radish. In pH analysis, Cheongjunggowon-radish had the highest value at 6.69±0.02. The pH in Mansahyungtong-radish showed the lowest value at 6.10±0.01. In the electronic tongue, sourness was high in the Seoho-radish (8.2), and saltiness was high in the Matdong-radish (8.1). Umami was high in the Seoho-radish (8.3), and sweetness was high in the Matdong-radish (8.1). In the electronic nose, sulfur-containing compounds were high in all the samples. Methanethiol, which represented the odor description of cabbage, garlic, and sulfurous, was abundant in sulfur-containing compounds. Multivariate analysis using physicochemical and chemosensory properties can be used as a database for the food industry.