• 한국식품영양학회지
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• 제9권3호
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• pp.289-293
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• 1996

Population changes of aerobic bacteria and lactic acid bacteria and changes of pH, acidity, and total sugar content were creased from initial period of fermentation. Lactic acid bacteria Increased during the first one nay rapidly and thereafter they creased slowly thereafter. Acidity increased on the third day of fermentation. Acidity was very low In Kimchi containing both Total sugar content decreased gradually from initial period to late period of fermentation.

• 한국대기환경학회지
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• 제11권1호
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• pp.69-76
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• 1995

Water content and strong acidity are estimated for ambient particles measured between Fall, 1991 and Summer, 1992 in Seoul using a gas/aerosol equilibrium model, called SCAPE. Particle water content and formation of solid species are closely related to ambient relative humidity and ionic concentrations. Generally, water content of particles is high during the night and summer. Estimated particle strong acidity level of Seoul is similar to that of Los Angeles, U.S.A. Acidity of wet and dry depositions in Seoul is discussed.

• Near Infrared Analysis
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• 제1권1호
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• pp.27-30
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• 2000

In this study, we investigated the feasibility of non-destructive determination of internal quality factors of Fuji apple fruit using near infrared(NIR) reflectance spectroscopy and developed the calibration models. As the reference methods, refractometer, titration and texture analyzer for sugar content, acidity and firmness were used, respectively. Samples were scanned from 1100∼2500nm with InfraAlyzer 500C spectrometer and SESAME software was used for data analysis. A multiple linear regression(MLR) analysis was performed to develop the calibrations. The correlation coefficient(R) and standard error of prediction(SEP) were as follows; 0.91, 0.41$^{\circ}$Brix for sugar content, 0.90, 0.04% for acidity and 0.84, 0.094 kg for firmness, respectively. This study shows that NIR spectroscopy can be used to evaluate the sugar content acidity and firmness of apple fruit with acceptable accuracy.

• 한국응용과학기술학회지
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• 제28권4호
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• pp.517-525
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• 2011

Squid ink was added to the low salt fermented squid by 4% of concentration and ripened at $10^{\circ}C$ for 6 weeks and at $20^{\circ}C$ for 28 days. The effect of the squid ink on the titrable acidity and free amino acids of low salt fermented squid were investigated. The results are as follows; The titrable acidity in the salt fermented squid without addition of the squid ink was continuously decreased except for the salt fermented squid with 9% salt content till the latter stage of the ripening, had larger decreasing range than treatment groups. Seeing the composition of free amino acid, the major amino acids are proline, arginine, glutamic acid. leucine and glycine.

• Korean Membrane Journal
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• 제2권1호
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• pp.56-59
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• 2000

The surface charge properties of a polymeric NF and a ceramic UF membranes were characterized in terms of zeta potential and acidity. Both the negative zeta potential and acidity values increased as pH increases due to ionizable acidic functional groups. Increased ionic strength reduced the acidity of the negatively-charged membrane surface as anticipated. Through these results, it can be envisioned are used to reject solutes with ionizable functional groups. Fouling of the negatively-charged membrane with natural organic matter (NOM) having a negative charge density was also investigated with respect to the surface charge. The surface charge of the NF membrane increased negatively when greater NOM adsorption onto the membrane surface occured.

• 한국산학기술학회논문지
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• 제5권1호
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• pp.73-77
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• 2004

프락토올리고당(fructooligosaccharide, FOS)의 첨가가 숙성 중인 김치의 산도와 맛에 미치는 영향을 검토하였다. FOS를 첨가한 경우 설탕을 첨가한 경우에 비하여 숙성 중의 김치의 pH와 산도 변화에 큰 영향을 주지 않았다 또한 FOS가 1％의 농도로 첨가된 김치는 신맛이 덜하고 전체적인 맛도 우수한 것으로 나타났으며 이취의 발생도 억제되었다.

• 대한가정학회지
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• 제38권2호
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• pp.21-26
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• 2000

Effect of aluminum dissolution from aluminum sauce pans with the kind and concentration of acidity, boiling times and temperature of acidity solution, in new and old sauce pans, and aluminum content in typical food was investigated. As acetic acid concentration increases, aluminum content has increased. But malic acid and citric acid have suddenly increased until acidity concentration would be 0.4%. After that rapidly increasing is not shown. As boiling time and temperature of acidity solution increases, concentration of aluminum dissolved from aluminum sauce pan has increased. Concentration of aluminum by repeated use has increased only a slightly. But aluminum content has dissolved in large quantities from new pan rather than old pan.

• Journal of Applied Biological Chemistry
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• 제42권1호
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• pp.48-49
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• 1999

• 한국대기환경학회지
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• 제13권1호
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• pp.9-18
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• 1997

Precipitation samples were collected by the wet- only event sampling method from Seoul during September 1991 to April 1995. These samples were analyzed for the concentrations of the major ionic components (N $O_3$$^{[-10]}$ , N $O_2$$^{[-10]}$ , S $O_4$$^{2-}$, C $l^{[-10]}$ , $F^{[-10]}$ , N $a^{＋}$, $K^{+}$, $Ca^{2＋}$, $Mg^{2＋}$, and N $H_4$$^{＋}$), pH, and electric conductivity. During the study period, a total of 182 samples were collected, but only 163 samples were used for the data analysis via quality assurance of precipitation chemistry data. The volume-weighted pH was found to be 4.7. The major acidifying species from our precipitation studies were identified to be non-seasalt sulfate (84$\pm$9 $\mu$eq/L) and nitrate (24$\pm$2 $\mu$eq/L) except for chloride. Because the Cl/Na ratio in the precipitation was close to the ratio in seawater. If all of the non-seasalt sulfate and nitrate were in the form of sulfuric and nitric acids, the mean pH in the precipitation could have been as low as 3.7 lower than the computed value. Consequently, the difference between two pH values indicate that the acidity of precipitation was neutralized by alkaline species. The equivalent concentration ratio of sulfate to nitrate was 3.5, indicating that sulfuric and nitric acids can comprise 78％ and 22％ of the precipitation acidity, respectively. Analysis of temporal trend in the measured acidity and ionic components were also performed using the linear regression method. The precipitation acidity generally showed a significantly decreasing trend, which was compatible with the pattern of the ratio (N $H_4$$^{＋}$＋C $a^{2＋}$)/ (nss-S $O_4$$^{2-}$＋N $O_3$$^{[-10]}$ ).).

• 한국표면공학회지
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• 제43권6호
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• pp.297-303
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• 2010

The effect of solution acidity and organic additives, polyethylene glycol (PEG), on the trivalent chromium electroplating was systematically investigated in the view point of electroreduction of trivalent chromium ions and solution stability. It was found that solution acidity controlled at pH 2.5 showed the widest current range for bright electrodeposits in the presence of PEG additives, which reduced the local current intensification at high current densities. Through complex interaction between PEG additives and hydrogen ion, that is, solution acidity, electrode potential was moved in the negative direction in the bulk solution, while it shifted in the positive when electric potential was scanned. In conjunction with electrochemical quartz crystal microbalance (EQCM), it was found that PEG additives had a role in promoting the electron transfer to trivalent chromium ion complexes in bulk solution and their adsorption at the electrode surface as well as interfering with hydrogen ion reduction process below pH 2.5. The PEG additives developed the nodular morphology during electroreduction of trivalent chromium ions with the increase of solution acidity and enhanced its current efficiency by maintaining the consumption of complexant, formic acid, at low speed.