• Food Science and Biotechnology
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• v.18 no.5
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• pp.1091-1095
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• 2009

The aim of this study investigated the fluctuations of 3 characters from 3 ecotypes [early ripening (ER), middle ripening (MR), and late ripening (LR)] of 20 Korean brown rice cultivars in different storage systems [time: 12 and 24 weeks, temperature: low ($10^{\circ}C$) and room ($25^{\circ}C$)]. With increase of storage time and temperature, lipoxygenase activity, and fat acidity increased, whereas germination rate was reduced. ER cultivars exhibited the highest lipoxygenase activity of $35.49{\pm}2.46$ unit/mg protein during 24 weeks storage at $25^{\circ}C$, followed by LR ($32.73{\pm}1.33$) and MR ($32.66{\pm}1.62$) cultivars. The amounts of fat acidity also were observed by the same order (ER: $20.40{\pm}2.12$>LR: $19.68{\pm}1.86$>MR: $19.64{\pm}1.35$ mg KOH/100 g). Germination rate slightly decreased with increase of time and temperature (MR>LR>ER), but MR and LR cultivars showed the most significant changes (ER: $60.90{\pm}23.47%$, MR: $32.66{\pm}13.95%$, and LR: $32.53{\pm}5.87%$). On the basis of above results, MR cultivars were evaluated the highest quality, because high lipoxygenase activity, high fat acidity, and low germination rate have deteriorated in quality and generated off-odor. Thus, MR cultivars might be very important sources in food processing and stored dietary supplement aspects.

• Journal of Korean Dental Science
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• v.17 no.1
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• pp.36-44
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• 2024

Purpose: This study investigated the effect of dentin bonding agent acidity on surface microhardness of MTA. Materials and Methods: Forty cylindrical molds (3 mm×5 mm) were prepared, and three dentin bonding agents with different acidities: Adper Single Bond 2 (ASB), Single Bond Universal (SBU), and Clearfil SE bond 2 (CSE) were applied to the inner surface of the molds (n=10). No bonding agent was applied in the control group. MTA was mixed and inserted into the molds and sealed with a wet cotton pellet for 4 days. After setting, the Vickers microhardness (HV) test was done at 200, 400, 600 ㎛ from the inner surface of the mold. One-way ANOVA was conducted for all samples. A P-value of less than .05 was considered significant. Tukey HSD test was performed for post-hoc analysis. Results: The mean HV values and standard deviations were 67.02±11.38 (Con), 48.76±11.33 (ASB), 43.78±11.19 (CSE), 37.84±9.36 (SBU), respectively. The difference between the control group and the experimental groups was statistically significant (P<0.001). The difference between ASB and SBU was statistically significant (P<0.001), while the difference between SBU and CSE was not. There were no statistically significant differences between the various points from the inner surface of the mold within each group (P>0.05). Conclusion: Results of the current study indicate that use of dentin bonding agents with MTA can reduce the surface microhardness of MTA. Moreover, there is a direct relationship between the acidity of dentin bonding agents and the surface microhardness of MTA.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.6
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• pp.768-777
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• 2013

Physicochemical characteristics and analysis of functional constituents of mulberry (Morus alba L.) fruit juices were investigated according to four different mulberry cultivars, including iksuppong, daeseongppong, cheongilppong and kwasangppong. Among the four mulberry cultivars examined, the small-sized cheongilppong had higher soluble solid content and lower titratable acidity, whereas the big-sized daeseongppong had higher titratable acidity and lower soluble solid content than other mulberry cultivars. Cheongilppong had higher contents of fructose and glucose, while daeseongppong had higher contents of citric and malic acids than the other mulberry cultivars. Kwasangppong had higher contents of two anthocyanins, cyanidin 3-glucoside and cyanidin 3-rutinoside, while cheongilppong had lower contents of two anthocyanins than the other mulberry cultivars. Daeseongppong had higher contents of resveratrols, flavonoids and moracin, whereas cheongilppong had higher levels of protocatechuic, chlorogenic and caffeic acids than the other mulberry fruits. Of the four mulberry cultivars, daeseongppong and cheongilppong had higher contents of GABA and DNJ, respectively, than the other mulberry cultivars. These results provide useful information to food technologists for the development and standardization of high quality mulberry juices as well as their processed foods.

• Food Science and Preservation
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• v.23 no.7
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• pp.967-976
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• 2016

The objective of the present study was to investigate differences in quality of kimchi products produced in Korea, Japan, and China. Kimchi products from kimchi-producing countries with high consumer consumption such as Japan and China along with local products from Korea, where exporting has not yet started, were collected. Product pH, acidity, salinity, package pressure, gas production were assessed, and microbiological analyses and sensory evaluations were performed on kimchi products that were stored at either $4^{\circ}C$ for 63 d or $15^{\circ}C$ for 20 d. The pH and acidity results showed that as Japanese and Chinese kimchi had higher pH and lower acidity than that of Korean kimchi, which was determined to be indicative of insufficient microbial fermentation following kimchi production. Japanese kimchi had different microbial properties than those of Korean kimchi, which is due to differences in their manufacturing processes. Overall preferences derived from sensory evaluations were: Korean kimchi>Chinese kimchi>Japanese kimchi. The results of this study demonstrate the sensory superiority of Korean kimchi and may be useful when predicting consumers' acceptance level of Korean kimchi exported to other countries.

• Journal of Korean Society for Atmospheric Environment
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• v.7 no.3
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• pp.203-207
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• 1991

Scientists in the National Institute of Environmental Research had carried out air and precipitation sampling. According to the data analysed, the acidity (pH) measured was in the range of 3.7 $\sim$ 5.5. Detailed analysis indicated that observed acid rain was associated with westerlies generally coming out of the mainland of China and with a cyclone formed therein. Emission of air pollution from Korea and Japan also appeared to contribute in the observed high acidity in some cases. The one of chief reasons for the occurrence of acid rain in the west coast of Korea was due to the increase in the total emission of air pollution in China. In 1990, China was the world's top producer of coal amounting in 1.05 B tons with an annual increase of 10%, and the produced 100 M tons of crude oil. $SO_2$ emission from all energy usage in China was estimated at 25 $\sim$ 50 M ton per year.

• Journal of Korean Society for Atmospheric Environment
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• v.2 no.2
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• pp.66-74
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• 1986

Rain samples were collected at 10 sites in the Seoul area during the period of August through November, 1985. THe concentrations of the major cations $(H^+, Ca^{++}, MG^{++}, Na^+, K^+, NH_4^+)$ and the major anions $(SO_4^=, NO_3^-, Cl^-)$ were measured to characterize the main sources of chemical ions in rainwater. Correlating concentrations of ions to pH, calculated coefficients ranged from 0.1485 to 0/4296. Sulfate shows the largest coefficient indicating that sulfate is more closely associated with hydrogen ion than other ions. This may suggest that sulfuric acid contributes more to the acidity of rainwater in Seoul. It appears that the major chemicals measured in rainwater are from the anthropogenic sources of air pollution. Predominant chemicals are acidic at the Guro-, the Sinseol-, the Yangnam-, and the Ssangmun-dong with sulfate being the most predominant. IT also indicates that alkaline substances resulting from soil and dust have a significant effect on pH values of rainwater by neutralizing actions. According to Granat-model analysis, it is estimated that the relative contributions to the rainwater acidity in Seoul are 84% from sulfuric acid, 8% from nitric acid and 8% from hydrochloric acid.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.1
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• pp.77-84
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• 1995

To prevent or reduce air pollutant from methanol fueled vehicles, methanol oxidation reaction was carried out using a heteropoly acid catalysts. Catalytic activities of catalysts have been experimented at atmospheric pressure in a fixed bed flow reactor. Catalysts were characterized by XRD, IR, thermal analysis, N $H_{3}$-TPD and GC pulse technique. Acidities of catalysts were highly affected by poly-atoms. Methanol conversion was much higher on catalyst with W than on catalyst with Mo as a poly-atoms. With the increase of copper content(X) in C $u_{x}$ $H_{{3-2x}}$PMo catalyst, acidity was decreased and oxidation ability was increased. Methanol conversion and product distribution were affected by the acidity and oxidation ability of catalyst. Especially, supported PdSiW(1wt%) catalyst has a very good methanol conversion and C $O_{2}$ selectivity as high as a commertial 3-way catalyst.t.

• Korean Journal of Food Science and Technology
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• v.1 no.1
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• pp.62-64
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• 1969

The experiment was carried out to investigate the adaptability of freezing process with thirteen strawberry varieties cultivated in Suwon, Pusan and Chunju area. Six of these were local varieties and the others were varieties imported from the United States of America. Each strawberries variety was analysed chemically to determine value of soluble solids, acidity (calculated as citric acid) and deepness of color. Frozen products were prepared by a general method adding sugar to $28^{\circ}\;Brix$. Local varieties Haengok, Bokuh, Keikwan and Daehak No. 1 were not suitable for making into frozen products because of excessive white color in their centers. Blakemore, an imported variety, was best as to color. Chemical analysis showed that imported varieties have higher acidity, and lower content of soluble solids. In a sensory test conducted by fifteen members of Agriculture and Fishery Development Corporation, deeper colors of strawberries did not receive a generally favorable response, and it was found that strawberry colors favored by the America were not liked by Korean well.

• Korean Journal of Plant Resources
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• v.24 no.2
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• pp.195-199
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• 2011

Tomato (Lycopersicon esculentum M.) is one of the most important crops to the fresh vegetable market and the food processing industry. To evaluate genetic variation in tomato fruits, major characteristics such as soluble solids, acidity and carotenoid contents were analyzed for 771 genetic resource lines. Lines in red color was about 85% which is the largest one followed by peach color, yellow, green, orange, and black. The sweetness of juice ranged from 2.2 to 11.5% (in brix), the average being 5.6%. The acidity ranged from 0.124% to 1.665%, and the average was 0.881%. The lycopine contents was up to 80.4 ${\mu}g/g$, and 43.4 ${\mu}g/g$ in average. ${\beta}$-carotine ranged 1.8 to 48.8 ${\mu}g/g$ and it average was 10.8 ${\mu}g/g$. Statistical analysis indicates that there is coefficient of correlation between acidity and sweetness, acidity and pH, pH and lycopine, lycopine and ${\beta}$-carotine. It is expected that the result of this study can be used for breeding more competitive species with respect to contents in sugar or functional chemicals from the selected characteristic species.

• Journal of the Korea Convergence Society
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• v.12 no.9
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• pp.185-191
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• 2021

In our study, we evaluated possibility of distillation process introduction for Korean Rubus coreanus balsamic vinegar production development, has a less complicated and more rapid process leading to higher production volumes and cost savings. In order to investigate the applicability of concentrated vinegar fraction (CVF) and distilled vinegar fraction (DVF) obtained from the distillation process as balsamic and distillation vinegar, acidity, pH, and specific gravity (S.G.) were measured for the vinegar fraction obtained from the distillation process. The acidity of final CVF (60% of initial volume) obtained 4 types of vinegar (acidity; 4.42, 4.84, 5.61, and 6.35) were increased mean 38.1%, compared to initial acidities. Especially, acidity and pH of the final CVF was similar to balsamic vinegar. In addition, acidity of DVF also increased and it of the final fraction was 4.41%, 4.95%, 5.88%, and 6.72%, respectively. And it was suggested that the final DVF could be used as distilled vinegar. In this study, it was confirmed that vinegar can be effectively concentrated through the distillation process, and distilled vinegar can be produced at the same time. However, it is thought that the introduction of the distillation process can be decided only after additional biochemical characteristics such as organic acid content and antioxidant activity measurement for each vinegar fraction are analyzed.