• Food Science and Preservation
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• v.14 no.5
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• pp.504-510
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• 2007

An extrusion process was to make an onion kimchi snack from rice grit and onion kimchi powder, in an effort to enhance the nutritional value, flavor, and physicochemical properties of the extrudate. This study investigated optimum conditions (moisture content, barrel temperature, and the content of onion kimchi powder) for the production of high-quality rice extrudate products, and measured quality properties (water absorption index, texture, expansion ratio, and color) of rice extrudate to which onion kimchi powder had been added. Onion kimchi powder at 3%, 5%, 7%, and 10% (all w/w) was mixed with rice grit and the mixture then extruded in a twin-screw extruder. The texture of onion kimchi mack became softer as onion kimchi powder level rose, and water absorption ability increased. The expansion ratio and the lightness of extrudates decreased with increases in onion kimchi powder levels. The maximum water absorption index am the minimum hardness were obtained with 10% onion kimchi powder. Rice extrudate with 10% onion kimchi powder was suitable for extrusion cooking md obtained the highest score for overall acceptability by sensory evaluation.

• Food Engineering Progress
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• v.14 no.2
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• pp.153-158
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• 2010

Changes in physicochemical properties of soybean pastes (Doenjang) of various salt contents (8-14%) during fermentation were investigated to explore the possibility of manufacturing a low salt soybean paste. Titratable acidity (TA) increased and consequently pH decreased with the fermentation time. The rates of TA and pH changes increased as the salt levels decreased. Protein contents remained unchanged and there were no differences among different salt levels. The amino nitrogen contents and the volatile basic nitrogen contents increased with fermentation time and showed higher values at lower salt levels. The reducing sugar contents increased from 6th to 11th week of fermentation, and decreased afterward. No remarkable differences in the reducing sugar contents were observed with respect to salt levels. Shorter fermentation periods were required at reduced salt levels. Appropriate fermentation periods of the 8, 10, 12 and 14% salt containing Doenjang were 2 to 11 weeks, 3 to 12 weeks, 6 to 14 weeks, and 9 to 15 weeks, respectively. Doenjang fermented for shorter period of time at lower salt content showed better sensory quality than that for longer period at higher salt content.

• Korean Journal of Ecology and Environment
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• v.47 no.3
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• pp.146-159
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• 2014

In this study, we evaluated the temporal changes of water quality in the 90 reservoirs in Korea and the relationships between water quality and their environmental factors in the reservoirs for effective management of reservoirs. The majority of study reservoirs were categorized as the eutrophic state based on Carlson's trophic index. Among 90 reservoirs, more than 55.0% were nutrient-rich based on $TSI_{TP}$ in each month, where more than 50.0% were nutrient-rich based on $TSI_{Chl-a}$ from June to November. Seasonal Mann-Kendall test was used to analyze temporal variation of water quality in the selected 60 reservoirs using monthly data from 2004 to 2008. The results showed that 27 (45.0%) reservoirs showed the improvement of water quality based on TP and Chl-a concentrations, while 14 (23.3%) and 11 (18.3%) reservoirs displayed the degradation of water quality based on TP and Chl-a concentrations, respectively. Meanwhile, a self-organizing map classified the study reservoirs into five groups based on differences of hydrogeomorphology (altitude, catchment area, bank height, lake age, etc.). Physicochemical factors and land use/cover types showed clear differences among groups. Finally, hydrogeomorphology of reservoirs were related to water quality, indicating that the hydrogeomorphological characters strongly affect water quality of reservoirs.

• Journal of Biosystems Engineering
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• v.41 no.4
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• pp.373-388
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• 2016

Background: Recent inquiries into high-quality foods have discussed the importance of the functional aspects of foods, in addition to traditional quality indicators such as color, firmness, weight, trimming loss, respiration rate, texture, and soluble solid content. Recently, functional Chinese cabbage, which makes up a large portion of the vegetables consumed in Korea, has been identified as an anticancer treatment. However, the investigation of practical issues, such as the effects of storage conditions on quality indicators (including functional compounds), is still limited. Purpose: We reviewed various studies on variations in the quality indicators and functional compounds of Chinese cabbage in response to different storage environments, focusing on storage temperature and storage period. In particular, we emphasized the effect of storage temperature and storage period on glucosinolate (GSL) levels, in order to provide guidelines for optimizing storage environments to maximize GSLs. Additionally, we used response surface methodology to propose experimental designs for future studies exploring the optimal storage conditions for enhancing GSL contents. Review: Large variations in quality indicators were observed depending on the cultivar, the type of storage, the storage conditions, and the harvest time. In particular, GSL content varied with storage conditions, indicating that either low temperatures or adequate air composition by controlled atmospheric storage may preserve GSL levels, as well as prolonging shelf life. Even though genetic and biochemical approaches are preferred for developing functional Chinese cabbage, it is important to establish a practical method for preserving quality for marketability; a prospective study into optimal storage conditions for preserving functional compounds (which can be applied in farms), is required. This may be achievable with the comprehensive meta-analysis of currently published data introduced in this review, or by conducting newly designed experiments investigating the relationship between storage conditions and the levels of functional compounds.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.137-145
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• 2018

This study was carried out to investigate the effect of carcass weight on the physicochemical and sensory traits of duck meat. In total, 150 duck carcasses were divided into five different weight groups. The fat content in both breast and leg meats tended to increase with increased carcass weight. The cooking loss was significantly higher in the <2,200 g weight group and decreased with increased carcass weight. There was no significant difference in pH, water-holding capacity, lightness, or redness among carcass weight groups. The shear force was significantly higher in the ${\geq}2,800g$ weight group. The oleic acid (C18:1, n9) content in both the breast and leg meats tended to increase with increased carcass weight. The unsaturated fatty acid content in the breast meats was similar for all the groups whereas its content in the leg meats increased with increased weight groups. There was no significant difference in the sensory scores among the treatments. Taken together, it may be said that the carcass weight had minor effects on the physicochemical traits of duck meat. Further studies are needed to determine the effects of different carcass weights in the same raising period on duck meat quality.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.4
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• pp.355-363
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• 1999

The experiments were carried out to elucidate the varietal variation of retrogradation in aged cooked rice and its association with some physicochemical properties of milled rice. The fifteen rice materials were selected from forty-three low-amylose japonica and Tongil-type rice cultivars based on palatability and retrogradation of cooked rice stratified by preliminary sensory evaluation of warm and cooled cooked rice. One japonica glutinous rice variety was included for comparison of retrogradation of cooked rice. The $\alpha$-amylase-iodine method was adopted for checking the varietal difference in retrogradation of cooked rice. The desirable checking time for evaluating the varietal difference in deterioration of aged cooked rice was four hours after storing in room temperature and two hours after preserving in refrigerator based on the largest coefficients of variations in degree of retrogradation of cooked rice. The rice cultivars revealing the relatively slow retrogradation in aged cooked rice were Ilpumbyeo, Chucheongbyeo, Sasanishiki, Jinbubyeo and Koshihikari. A Tongil-type rice, Taebaegbyeo, and a japonica cultivar, Seomjinbyeo, showed the relatively fast deterioration of cooked rice. The retrogadation index represented by the percentage of retrogradation difference between warm and cooled cooked rice to original estimates of warm cooked rice was significantly affected by the degree of retrogradation of cooled cooked rice. Generally, the better rice cultivars in eating quality of cooked rice showed less retrogradation and much sponginess in cooled cooked rice. Also, the rice varieties exhibiting less retrogradation in cooled cooked rice revealed higher hot viscosity and lower cool viscosity of rice flour in amylogram. The sponginess of cooled cooked rice was closely associated with magnesium content and volume expansion of cooked rice. The hardness-changed ratio of cooked rice by cooling was negatively correlated with solids amount extracted during boiling and volume expansion of cooked rice. The major physicochemical properties of rice grain closely related to the palatability of cooked rice may be directly or indirectly associated with the retrogradation characteristics of cooked nce. The varietal difference in retrogradation of cooked rice can be effectively classified by scatter diagram on the plane of upper two principal components based on some retrogradation properties of cooked rice. The deteriorated structural change in cooled cooked rice by observing through the scanning electron microscope was more conspicuous in the fastly retrograded cooked rice than in the slower one.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.6
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• pp.839-847
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• 2011

Fermented compost made from medicinal herb waste (MHWC) as an environment-friendly manure was applied to determine the physicochemical characteristics of Rubus coreanus Miquel (Bokbunja). MHWC, poultry manure compost (PMC), and MHWC+PMC (1:1, w/w) were applied to 2 year-old Bokbunja plants at levels of 0 (UC: untreated control), 20, and 40 Mg/ha, respectively. The physicochemical characteristics of Bokbunja were investigated 15, 20, and 25 days after flowering (DAF). There were no differences between the chemical compositions of the group. However, the total sugar contents of the fruit harvested 15, 20, and 25 DAF from MHWC were increased 0.54~0.56, 0.46~0.53, and 1.80~2.52%, respectively, as compared with UC. The free sugar content in fruit from the MHWC group was higher compared to the other groups. The fructose and glucose contents were increased 0.08~0.31% and 0.08~0.18%, respectively. The organic acid content of the fruit was increased in the MHWC and PMC groups, and citric acid constituted 92.67~93.59% of the total organic acid content. In conclusion, MHWC treatment is a compost source for quality improvement of total sugar, free sugar, and organic acid contents of Bokbunja.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.2
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• pp.187-194
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• 2009

The aim of this study was to investigate the physicochemical characteristics of native Korean Allium wakegi Araki samples, which were grown from seven local seed bulbs(Yesan, Muan, Anmyon-do, Deokjeok-do, Jeju-do, Yecheon, and China) to produce high quality native Korean Allium wakegi Araki. For the proximate composition of samples, moisture contents were in the range of 90.69~92.43%. The crude protein content of the Jeju-do sample was highest compared to the other samples. However, there were no significant differences in total sugar contents between samples. The seed bulb origin did not affect the hardness of the stem part, but was high for the leaves of the Yesan sample compared to the other samples. The results for anti-oxidative activity were as follows: Yesan(2.30 mg/mL) > China(2.51 mg/mL) > Muan (2.56 mg/mL) > Yecheon(2.74 mg/mL) > Jeju-do(2.85 mg/mL) > Anmyon-do(2.87 mg/mL) > Deokjeok-do(3.18 mg/mL). In terms of mineral and amino acid contents, the Yesan sample showed the highest levels, respectively, compared with the other samples. Food values such as contents of total phenolics and pyruvic acid were highest in the Jeju-do sample. These results show that the physicochemical characteristics of Allium wakegi Araki were significantly different according to different seed bulb origins.

• Food Science of Animal Resources
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• v.29 no.2
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• pp.213-219
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• 2009

This study was conducted to investigate the changes in the physicochemical properties of five muscles from low-fat pork cuts during storage at $4^{\circ}C$ for 14d. As the chilled-storage time increased, the moisture and fat contents and the pH of the muscles did not significantly (p>0.05) change, but the water-holding capacity of the supraspinatus, semitendinosus, and longissimus dorsi muscles significantly (p<0.05) improved. The purge loss of the five muscles significantly (p<0.05) increased with the increase in the storage time, but their cooking loss and hardness did not significantly (p>0.05) change as the chilled-storage time increased. It can be seen from these results that the physicochemical properties of the five muscles do not changes greatly during the 14-day cold storage. Therefore, it is possible to distribute such five pork muscles to fresh-pork-meat retail stores or shops without meat quality degradation.

• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.649-654
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• 1994

In order to provide a quality index of Korean folk sojues, physicochemical properties of Korean folk sojues (Andong soju, Moonbaesul, Leekangju, Jindo Hongju, Chebiwon soju, Yethyang (rice) and Yethyang (barley)), Paekrosul, Chinese kaoliangchiews (Moutaichiew, Ergoutoutiu, Chuyehchingchiew, Zhikukaoliangchiew and Paigal), Japanese Senbatanuki shochu and two whiskies were determined. The pH of sojues ($3.43{\sim}5.85$) were mainly influenced by total acidity which was described as acetic acid. The conductivities of Paekrosul and Leekangju showed relatively high value of $246\;and\;122.7{\mu}S/cm$, respectively. Korean folk sojues and Paekrosul showed maximum absorption at 274 or $278{\sim}280nm$ in the spectrometric study. We performed principal components analysis (PCA) of physicochemical properties and spectrometric data to extract representative characteristics and to compare the similarity or the dissimilarity. The PCA plot showed the distinguished cluster of Korean folk sojues comparing with Chinese kaoliangchiew or Paekrosul etc.