• Journal of Advanced Marine Engineering and Technology
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• v.25 no.6
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• pp.1341-1352
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• 2001

Vacuum freeze drying process by which frozen water in a drying material is removed sublimation under vacuum condition, is now applied to various industrial field such as the manufacturing and packaging of pharmaceuticals in pharmaceutical industry, the drying of bio- products in bio-technology industry, the treatment of various quality food stuff in food technology, and so on. The Knowledge about the heat and mass transfer characteristics related with the vacuum freeze drying process is crucial to improve the efficiency of the process as well as the quality of dried products. In spite of increasing needs for understanding of the process, the research efforts in this fields are still insufficient. In this paper, a numerical code that can predict primary drying in a vial is developed based on the finite volume method with a moving grid system. The calculation program can handle the axis- symmetric and multi-dimensional characteristics of heat and mass transfer of the vial freeze drying process. To demonstrated the usefulness of the present analysis, a practical freeze drying of skim Milk solution in a vial is simulated and various calculation results are presented.

• Food Science and Preservation
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• v.16 no.1
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• pp.134-137
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• 2009

The gelatin film containing grapefruit seed extract (GSE) was prepared by incorporating different amounts (0, 0.02, 0.05, 0.08, 0.1%) of GSE into the film. The tensile strength (TS) of the film increased by the addition of GSE, and water vapor permeability (WVP) of the film decreased. In particular, the gelatin film containing 0.1% GSE had a TS of 10.28 MPa, while the control had 8.68 MPa. WVP of the film containing 0.1% GSE decreased to 2.18 ng m/m2 s Pa, compared to 2.48 ng $m/m^{2}s$ Pa of the control. In addition, incorporation of 0.1% GSE to the gelatin film decreased the populations of Escherichia coli O157:H7 and Listeria monocytogenes by 2.67 and 3.15 log CFU/g, respectively, compared to the control. These results suggest that as a packaging material, gelatin film containing GSE can have antimicrobial activity against pathogenic microorganisms in foods.

• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.1-14
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• 2023

Polyethylene terephthalate (PET) is a plastic material commonly applied to beverage packaging used in everyday life. Owing to PET's versatility and ease of use, its consumption has continuously increased, resulting in considerable waste generation. Several physical and chemical recycling processes have been developed to address this problem. Recently, biological upcycling is being actively studied and has come to be regarded as a powerful technology for overcoming the economic issues associated with conventional recycling methods. For upcycling, PET should be degraded into small molecules, such as terephthalic acid and ethylene glycol, which are utilized as substrates for bioconversion, through various degradation processes, including gasification, pyrolysis, and chemical/biological depolymerization. Furthermore, biological upcycling methods have been applied to biosynthesize value-added chemicals, such as adipic acid, muconic acid, catechol, vanillin, and glycolic acid. In this review, we introduce and discuss various degradation methods that yield substrates for bioconversion and biological upcycling processes to produce value-added biochemicals. These technologies encourage a circular economy, which reduces the amount of waste released into the environment.

• Korean journal of food and cookery science
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• v.28 no.2
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• pp.207-214
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• 2012

In this study, cabbage ($Brassica$ $oleracea$ var. $capitata$) Kimchi was made packed into four kinds of packaging materials, PET vessel, PP tray, OPP/AL/PE film and Nylon/PE/LLDP film, and the effects of these packaging materials on Kimchi quality characteristics, such as lactic acid bacteria counts, salinity, sugar contents, pH, total acidity, electron donating ability were examine as well as their effects on the sensory qualities after storage at a temperature of $4^{\circ}C$. The pH change ranged from pH 6.24 to 6.43 shortly after manufacture, and did not significantly change until 7 days of storage. However, it began to decrease rapidly after 14 days. On the 35th day of storage, the acidity was 0.79% in the PET vessel and 0.83% in OPP/AL/PE. Therefore, the PET vessel and OPP/AL/PE were considered appropriate packaging materials for Kimchi storage. The salinity did not change significantly during the storage period, and the sugar content generally increased in the four kinds of packaging materials, but decreasing after the 7th day of storage. After 14 days of storage, the Kimchi stored in the OPP/AL/PE film showed the highest lactic acid bacteria counts. Although the electron donating ability was the highest after proper time for fermentation, it decreased in all the packaging materials after the proper time for fermentation. However, the OPP/AL/PE film had an antioxidant potential of up to 93.18%. In the sensory evaluation, fermented Kimchi was found to be superior unfermented Kimchi. In addition, the Kimchi stored in the OPP/AL/PE film for 14 days showed the high score of 6.70 and 6.60 in overall preference. Therefore, the results of this study provide basic knowledge on the fermentation level and packaging material's condition for commercialization of small packed cabbage Kimchi. Henceforth, industrialization must include a variety of studies under these conditions to increase the merchantability.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.449-457
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• 1995

Aseptic packaged cooked rice without oxygen absorber and EVOH material was not suitable for good quality during long storage at room temperature. Quality change of aseptic packaged cooked rice with OPP/EVOH/EPL(P-1), PET/EVOH/EPL(P-2) and OPP/EVOH/LLDPE(P-3) for lid material and FX and TSQ for oxygen absorber was observed during storage(60 days) at $20^{\circ}C,\;30^{\circ}C\;and\;40^{\circ}C$. To evaluate quality change of aseptic packaged cooked rice, water content, color, pH, acidity, hardness, and total plate count were measured periodically. The results showed that moisture content was decreased as storage time increased while storage temperature showed no significant effect. P-2 and FX combination had the lowest evaporation of water. L value was decreased as storage time increased while a value increased in all treatment. P-2 and FX combination had the best result for color value. Titratable acidity and pH of P-3 increased up to 20, 5.5, respectively at the end of storage while the other treatment showed no significant effect. Hardness of aseptic packaging of cooked rice was decreased as temperature of storage increased while lid materials and oxygen absorber types showed no significant effect. Result of total plate count showed that there was no detection for $20^{\circ}C\;and\;30^{\circ}C$ storage temp. while more than $1{\times}10^6\;CFU/g\;for\;40^{\circ}C$ storage temp. at the end of storage. In conclusion, aseptic packaged cooked rice could be stored and distributed for 6 month at room temp. and effect of lid materials on quality change of aseptic packaged cooked rice was more significant than oxygen absorber.

• Korean Journal of Food Science and Technology
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• v.29 no.2
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• pp.390-393
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• 1997

${\kappa}-Carrageenan-based$ film prepared by mixing 2% ${\kappa}-carrageenan$, 0.1% KCl, 0.75% polyethylene glycol, and 0.75% glycerol was examined to be used as a potential packaging material for mackerel mince for preventing moisture loss and lipid oxidation. Mackerel mince patties were vacuum-packaged with the film and stored at $20^{\circ}C,\;10^{\circ}C,\;0^{\circ}C,\;and\;-15^{\circ}C$; nonpackaged patties were also stored at $0^{\circ}C$. Weight reduction, peroxide value (PV), and thiobarbituric acid (TBA) value were measured during storage. The packaged or nonpackaged samples stored at $20^{\circ}C,\;10^{\circ}C,\;and\;0^{\circ}C$ showed a 60% weight reduction between 2 and 15 days of storage, while the weight reduction of the samples stored at $-15^{\circ}C$ was about 3% after 25 days. The nonpackaged samples stored at $0^{\circ}C$ showed a steady increase in lipid oxidation with the PV reaching 23 mequivalent peroxide (PO)/㎏ on day 20 and with the TBA value at 0.4 mole malonaldehyde (MA)/g on day 5. The PV and TBA values of the samples vacuum-packaged with the carrageenan-based film were below 2 mequivalent PO/㎏ and below 0.1 mole MA/g, respectively, regardless of storage temperature throughout the storage of 28 days.

• Journal of Food Hygiene and Safety
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• v.36 no.4
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• pp.281-288
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• 2021

This study was conducted to analyze and compare the concentrations of heavy metals in 430 different products of 20 types of herbal medicines available in the domestic market in Korea by Graphite Furnace-Atomic Absorption Spectrometry (GF-AAS) and automated mercury analyzer. The accuracy for lead (Pb), arsenic (As), cadmium (Cd), and mercury (Hg) was in the range 92.67-102.56%, and the precision was 0.21-6.00 relative standard deviation (RSD%), which was in compliance with the Codex acceptable range. Furthermore, the Food Analysis Performance Assessment Scheme (FAPAS) quality control (QC) material showed a recovery range of 96.7-102.0% and 0.33-4.93 RSD%. The average contents (㎍/kg) of Pb, As, Cd, and Hg in herbal medicines were 254.9 (not detected (N.D.)-2,515.2), 171.0 (N.D.-2,465.2), 99.2 (N.D.-797.1), and 6.0 (N.D.-83.6), respectively. Based on the quantitative analysis results, the heavy metal contents of 20 types of herbal medicines distributed in Korea are within the acceptable range according to the standards issued by the Ministry of Food and Drug Safety (MFDS). By using the manufacturer of herbal products as the standard for QC, the Pb, As, Cd, and Hg contents were investigated in the packaging process just before distribution to determine the actual conditions of residual heavy metals in herbal medicines. Thus, these result may contribute to monitoring the QC of herbal medicines distributed in Korea and could provide basic data for supplying safe herbal medicines to the public.

• Journal of Microbiology and Biotechnology
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• v.16 no.7
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• pp.1053-1059
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• 2006

The effectiveness of a proteinaceous fibrous material formed during commercial fermentation of soy protein (PFSP) and cysteine addition were evaluated in order to improve on the properties of soy protein-based films. Nine types of films were prepared at pH 7, 9, and 11, with heat treatments at $70^{\circ}C\;and\;90^{\circ}C$ for 30 min, by casting 5% (w/w) PFSP aqueous solution, containing 2.25% (w/w) glycerol, on to polystyrene plates. The tensile strength (TS) of films ranged from 3.88 to 6.87 MPa. The highest puncture strength (PS) was observed with pH 7.0 films prepared from PFSP solution heated at $70^{\circ}C$ (P<0.05). Alkaline pH and temperature caused a decrease in both the TS and PS of the films. The thickness of films ranged from $58\;to\;74{\mu}m$. Water vapor permeabilities of the films decreased with increasing pH and temperature. To produce films from PFSP, pH value of 7.0 to 9.0 and heat treatment of $70^{\circ}C\;to\;90^{\circ}C$ were needed. A soluble nature of PFSP films in water might be useful for preparation of hot water-soluble pouches. Cysteine addition could be necessary to produce films with increased TS and enhanced barrier properties. The combination treatment that provided the best combination of barrier and mechanical properties was the PFSP film prepared at pH 7.0 with addition of 1% cysteine. The films were good oxygen barriers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.6
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• pp.1056-1062
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• 2004

Migration of low molecular weight components from expanded polystyrene (ESP) to distilled water was measured at different temperature conditions. Overall migration and specific monomer migration were measured. Diffusion model based on Fick's law was used to determine the apparent diffusion coefficients at various experimental conditions. The overall and specific migration levels were estimated to give some practical implications for regulatory guideline development and safe package design. Diffusion coefficients for overall migration in KMnO$_4$ oxidizable extractives and specific migration of styrene monomer from ESP at 6$0^{\circ}C$ were 0.030 and 6.8${\times}$10$^{-5}$ $\textrm{mm}^2$/h, respectively. Their temperature dependence could be explained by Arrhenius equation with respective activation energies of 80.5 and 98.6 kJ/㏖. Experimental conditions ensuring desired migration level were suggested for reliable examination of migration from the packaging material. Some explanatory estimations of migrations were given for some typical conditions of potential usages.

• The Korean Journal of Food And Nutrition
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• v.25 no.4
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• pp.1092-1098
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• 2012

Aroma compounds in sun-dried salt according to saltern material and packaging box were extracted by the headspace and were isolated by using GC-MS. These compounds were identified including ketones, heterocyclic compounds and six other compounds. Major aroma compounds in salts were identified as 4-methyl-2-pentanone, 5-methyl-3-hexanone, 4-methyl-3-penten-2-one, 2-hexanol, benzothiazole, 2,4-bis(1,1-dimethylethyl)-phenol, and 1,3,5-tri-tert-butyl benzene. However, we found no significant differences according to the saltern materials in three salts. Salts stored in Chamaceyparis obtusa (Sieb. et Zucc.) had more diverse aroma profiling than those in Pinus densiflora and Paulownia coreana. We consider that it need to research the development of high value added products for new aromatic salt.