• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1687-1692
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• 2015

Since the domestic grape wine industry has been stagnant, the quality of Korean wine must be improved to compete with imported wines. For improving the quality of domestic wine up to 'unfined' or 'unfiltered' wine, this study investigated the possibility of producing 'unfined' or 'unfiltered' wine and their physicochemical characteristics. Muscat Bailey A as a domestic grape was selected to make wine. Prior to refining process after alcohol fermentation, the wine samples were divided into three specimens depending on the treatment of bentonite for clarification and filter (sample A treated with both bentonite and filter, sample B treated with bentonite only, and sample C treated without bentonite and filter). The physicochemical characteristics of each specimen after one week matureness were then investigated. Sample C showed highest values in total phenol and organic acid content among others. Samples B and C showed more stability in intensity, hue, and color. Although it is hard to compare domestic wine with imported wine, it may be possible to improve the quality of domestic wine and contribute to the development of the domestic wine industry when further studies are conducted on in-depth fermentation of wine and improvement of microbiological stability.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.1
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• pp.17-26
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• 2018

This study aimed to investigate the effects of vacuum packaging on the quality characteristics of frozen Tteokgalbi made from spent laying hen meat and mechanically deboned chicken meat (MDCM). The samples were prepared with different levels of added MDCM; C (0%), T1 (20%), T2 (40%), and T3 (60%). The samples were allocated for microbiological and physico-chemical analyses after 0, 45, and 90 days at $-18^{\circ}C$, with or without vacuum packaging. After 90 days of storage, the values of volatile basic nitrogen were significantly lower in the vacuum packaged samples compared to the non-vacuum samples, irrespective of the added levels of MDCM (p<0.05). Sensory results at day 0 of storage showed that the texture scores of C and T1 samples were significantly higher than those of T2 and T3, while the flavor scores were the lowest for the T3 samples (p<0.05). In addition, with increased storage duration, the texture and flavor attributes of the vacuum-packaged samples were found to be higher than those of non-vacuum samples. In general, the vacuum-packaged samples tended to show superior physico-chemical quality characteristics compared to the non-vacuum samples, when the storage time was extended up to 90 days.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.6
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• pp.853-859
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• 2007

This study investigated the quality characteristics of bread made with different additions of Chungkukjang powder (0, 10, 20%). In the microbiological evaluations, total aerobic bacteria increased with increases in Chungkukjang powder concentration and storage period ($20^{\circ}C$, 3 days). The pH also increased with increasing Chungkukjang powder concentration. For the color values, with increasing Chungkukjang powder content, the lightness (p<0.05) decreased in both the bread crumb and crust, while redness (p<0.05) increased. The yellowness decreased for the bread crust and increased for the bread crumb. Hardness and chewiness were higher, but springiness and cohesiveness were lower, in the breads made with 10 or 20% Chungkukjang powder as compared to the control. The control bread obtained the highest sensory scores for texture and overall acceptability during the storage period. Optimum sensory scores for color, texture, and overall acceptability were obtained for the bread with 10 % Chungkukjang powder until day 1 of storage. From the results of this study, 10% Chungkukjang powder can be added to bread without diminishing its acceptability, but further study is necessary on extending shelf-life and improving consumer acceptance.

• Journal of the Korean Society of Food Culture
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• v.34 no.2
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• pp.224-232
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• 2019

This study evaluated the physicochemical and microbial quality characteristic of seasonal commercial kimchi for hygienic safety levels. The pH of seasonal commercial kimchi was 3.84-6.36 and the titratable acidity and salinity of the samples were 0.21-1.16 and 1.19-1.54%, respectively. The content of nitrate and nitrite in the commercial kimchi were lower in the spring and summer, which was affected by acidic condition of the kimchi depending on fermentation. Heavy metal contents in commercial kimchi are not an issue because they were detected only at very low levels. The total aerobic bacteria and coliforms counts ranged from 5.25 to 8.44 Log CFU/g and 0.00 to 5.08 Log CFU/g, respectively. The total aerobic bacteria and coliforms were detected more in summer than in the other seasons. E. coli was detected in three of the samples tested. Food-borne pathogens were not detected in any of the samples except for B. cereus. B. cereus was detected in the fall in more than 70% of samples. These results suggest that commercial kimchi distributed in the fall maintain the quality properties and the microbiological safety of kimchi compared to the other seasons. Therefore, further studies as an effective distribution system for the particular seasons will be needed to guarantee the hygienic safety levels of commercial kimchi required by the consumers.

• Korean Journal of Agricultural Science
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• v.34 no.1
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• pp.67-75
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• 2007

The effect of irradiation on the quality characteristics of pale-soft-exudative (PSE) pork was studied. The pork loin with severe PSE appearance was selected by meat grader,irradiated at 0 and 4.5 kGy, and meat quality characteristics including pH, color, lipid oxidation development, microbial and sensory quality were analyzed during 2 weeks of storage at $4^{\circ}C$. The pH values of non-irradiated and 4.5 kGy-irradiated PSE raw pork loin was not different. Hunter color $a^*$-value, which represents redness of meat surface showed significant increase (P<0.05) in irradiated PSE pork loin. This higher Hunter color $a^*$-value maintained during 2 weeks of storage. By 4.5 kGy of irradiation, approximately 2 log reduction of total aerobic bacterial counts was achieved during 2 weeks of storage when compared with non-irradiated control. Sensory panelists prefer the color of irradiated PSE meat than that of non-irradiated control because of redness. From the results, it is possible to use an irradiation technology to improve not only microbiological safety but also the color of meat which has severe defect such as PSE.

• Korean Journal of Food Science and Technology
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• v.23 no.5
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• pp.527-531
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• 1991

Frozen mandu, which is one of the main frozen prepared foods, purchased from a local manufacturer, were stored at five constant temperatures ($0,\;-5,\;-10,\;-20\;and\;-30^{\circ}C$) for six months. Effects of the storage temperature and the storage period on the changes in pH, acid value, peroxide value, volatile basic nitrogen, color, sensory score and microbial counts of frozen mandu were studied. The changes in microbiological and physicochemical characteristics were significantly increased in comparison with the initial value after 1 month at $0^{\circ}C$, after 3 months at $-5^{\circ}C$ and after 5 months at $-10^{\circ}C$, but nearly constant in spite of storage periods when the temperature dropped below $-10^{\circ}C$Out of five chemical components, AV and POV were the most reliable components in the quality judgement of frozen mandu and its upper limiting content were 2.56 and 19.35 meq/kg each. Regression equation for shelf life prediction of frozen mandu with sensory scores and POV was determined.

• Animal Bioscience
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• v.36 no.10
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• pp.1596-1603
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• 2023

Objective: Sous-vide cooking offers several advantages for poultry meat, including enhanced tenderness, reduced cooking loss, and improved product yield. However, in duck meat, there are challenges associated with using the sous-vide method. The prolonged cooking time at low temperatures can lead to unstable microbial and oxidative stabilities. Thus, we aimed to assess how varying sous-vide cooking temperatures and durations affect the physicochemical and microbial characteristics of duck breast meat, with the goal of identifying an optimal cooking condition. Methods: Duck breast meat (Anas platyrhynchos) aged 42 days and with an average weight of 1,400±50 g, underwent cooking under various conditions (ranging from 50℃ to 80℃) for either 60 or 180 min. Then, physicochemical, microbial, and microstructural properties of the cooked duck breast meat were assessed. Results: Different cooking conditions affected the quality attributes of the meat. The cooking loss, lightness, yellowness, Hue angle, whiteness, and thiobarbituric acid reactive substance (TBARS) values of the duck breast meat increased with the increase in cooking temperature and time. In contrast, the redness and chroma values decreased with the increase in cooking temperature and time. Cooking of samples higher than 60℃ increased the volatile basic nitrogen contents and TBARS. Microbial analysis revealed the presence of Escherichia coli and Coliform only in the samples cooked at 50℃ and raw meat. Cooking at lower temperature and shorter time increased the tenderness of the meat. Microstructure analysis showed that the contraction of myofibrils and meat density increased upon increasing the cooking temperature and time. Conclusion: Our data indicate that the optimal sous-vide method for duck breast meat was cooking at 60℃ for 60 min. This temperature and time conditions showed good texture properties and microbial stability, and low level of TBARS of the duck breast meat.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.3
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• pp.213-220
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• 2018

This study was conducted to investigate changes in the quality of Gochujang following the addition of sea tangle Saccharina japonica powder fermented by lactic acid bacteria (FSP). Gochujang was prepared with or without FSP and fermented at $16^{\circ}C$ for 24 weeks, as detailed in a previous study. No significant physicochemical changes in moisture, crude protein content, pH, salinity and amino nitrogen content were observed among the varieties of Gochujangs evaluated (Commercial Gochujang, Gallic-Gochujang and FSP-Gochujang). In addition, we detected no significant differences in microbiological profiles. However, following addition of FSP to Gochujang, the color was affected and antioxidant properties were enhanced. The DPPH radical scavenging activity of FSP-Gochujang increased by 58.8% and 24.8% compared with Commercial Gochujang and Gallic-Gochujang, respectively. Furthermore, analysis of the free amino acid content revealed higher levels of ${\gamma}$-Aminobutyric acid (100.9 mg/100 g), a biofunctional ingredient, in FSP-Gochujang. Thus, these results suggest the potential for development of a traditional Korean fermented food with enhanced antioxidant activity and ${\gamma}$-Aminobutyric acid content using FSP.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.6
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• pp.769-776
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• 2022

As an aquatic plant, the lotus leaf Nelumbo nucifera is rich in polyphenols, carotenoids, and flavonoids. We analyzed the chemical (pH, acidity, sugar, alcohol), microbiological (lactic acid bacteria, yeast), and antioxidant activity of Makgeolli supplemented with 5% and 10% lotus leaf (ll) during fermentation for 7 days. The pH of the non-additive group (control) was 3.10-6.03, that of the 5% added group was 3.17-5.77, and that of the 10% added group was 3.27-5.70, which decreased significantly (P<0.05) as the fermentation time elapsed. The acidity and sugar content were 1.89-2.12% and 9.10-12.90 Brix, respectively, which were significantly higher (P<0.05) as the amount of added ll increased. The alcohol content was 5.90-7.20% and was the highest on the seventh day of fermentation. The lactic acid bacteria was 6.07-7.17 log CFU/mL, which was higher in ll Makgeolli. Yeast increased until day 3 and then decreased to 3.27-5.86 log CFU/mL. DPPH (1,1-diphenyl-2-picrylhdrazyl) and ABTS [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging activities were higher in ll Makgeolli (DPPH 68.72-81.48%, ABTS 90.71-91.67%). In this study, the commercialization potential of ll Makgeolli was expanded by enhancing the quality and antioxidant function of Makgeolli added with ll.

• Food Science of Animal Resources
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• v.44 no.1
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• pp.146-164
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• 2024

Owing to the residual toxicity and adverse health effects of chemical preservatives, there is an increasing demand for using natural preservatives in food. Although many natural extracts have been evaluated, research on their antibacterial effects remains insufficient. Therefore, this study aimed to explore the possibility of developing Psidium guajava, Ecklonia cava, and Paeonia japonica (Makino) Miyabe & Takeda extracts as natural food preservatives. Further, the effect of mixing these extracts on microbial growth and quality was evaluated during the refrigeration of sausages. Optimal mixing ratios were determined based on the minimum inhibitory and bactericidal concentrations of each mixed extract against the Listeria monocytogenes, Salmonella spp. and Escherichia coli. D-optimal mixing design optimization tool was further used to obtain an optimum mixing ratio of Formulation 1 (F1). The antibacterial activity of F1 increased with increasing concentration, with similar activities at 0.5% and 1%. The sausages with synthetic or natural preservatives showed significantly lower lipid oxidation than those of the control and grapefruit extract-treated sausages after 4 wk of refrigeration. Total plate counts were observed only in the control and treatment groups stored for 3 wk, and no significant effect of ascorbic acid was observed. Compared to the other samples, sausages with added natural extracts showed the highest overall acceptability scores initially and after 4 wk. Therefore, similar amounts of grapefruit seed and natural extracts had the same effect on microbiological analysis and lipid rancidity during sausage storage. Hence, this mixture can serve as a potential natural preservative in meat products.