• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제2권2호
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• pp.109-114
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• 1998

The induction of crassulacean acid metabolism(CAM) characterized by day/night acid fluctuation was investigated in leaves from 10 days exposure to elevated $CO_2$ concentration(1,000 ${\mu}L\;L^{-1}CO_2).$ For Pereskia aculeata, have $C_3-like$ gas exchange pattern in well watered condition and shift into CAM-like in water stress, showed a more typical CAM-like diurnal acid fluctuation. Whereas the massive diurnal fluctuation of acidity in typical CAM of Kalanchoe rosea was declined. The effect of short-term exposure to various concentrations of $CO_2$ on titratable acidity in P. aculeata and K. rosea was also investigated. To investigate the response of various $CO_2$ concentrations, four different $CO_2$ levels(350, 700, 1,000 and 1,500 ${\mu}L\;L^{-1})$ were imposed for 24hr and measured the titratable acidity at 06:00, when the acidity was maximum, and 14:00, when the acidity was minimum. The accumulation of acid in P. aculeata was enhanced markedly by higher concentration of $CO_2,$ while the level of acidity in f rosea did not highly respond to $CO_2.$ A notable difference between P. aculeata and K. rosea was the response of de-acidification to a higher concentration of $CO_2$ Increasing with $CO_2,$ the degree of do-acidification of P. auleata was increased while that of K. rosea was depressed.

• 한국식품저장유통학회지
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• 제11권1호
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• pp.34-37
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• 2004

유청칼슘을 0.5%, 1.0% 및 1.5%씩 첨가하여 만든 김치를 1$0^{\circ}C$에서 숙성시키면서 pH, 적정산도, 환원당 함량, 총균수 및 유산균수를 측정한 결과는 다음과 같았다. 김치의 담금 직후부터 유청칼슘을 첨가한 시험구가 대조구보다 높은 pH를 유지하였다. 숙성 5일까지는 시험구간에 적정산도의 차이가 거의 나타나지 않았으나 그 이후에는 유청칼슘을 첨가한 시험구의 적정산도가 대조구보다 모두 높았다. 특히 유청칼슘의 첨가량이 많을수록 적정산도가 높았다. 유청칼슘을 첨가한 시험구는 김치 담금시부터 총균수 및 유산균가 많았으며, 유청칼슘의 첨가량이 많을수록 총균수 및 유산균수가 더 많았다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.II
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• pp.210-218
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• 2000

Since the SSC(soluble solid contents) and titratable acidity of fruit are highly concerned to the taste, the need for measuring them by non-destructive technology such as NIR(Visual and Near-infrared) spectroscopy is increasing. Specially, in order to grade the quality of each fruit with a sorter at sorting and packing facilities, technologies for online measurement satisfying the tolerance in terms of accuracy and speed should be developed. Many researches have been done to develop devices to measure the internal qualities of fruit such as SSC, titratable acidity, firmness, etc. with the VIS(Visual)/NIR(Near Infrared) reflectance spectra. The distributions of the SSC, titratable acidity, firmness, etc. are different with respect to the position and depth of fruit, and generally the VIS/NIR light can interact with fruit in a few millimeters of pathlength, and it is very difficult to measure the qualities of inner flesh of fruit. Therefore, to measure the average concentrations of each quality factor such as SSC and titratable acidity with the reflectance-type NIR devices, the spectra of fruit at several positions should be measured. Recently, the interest about the transmittance-type VIS/NIR devices is increasing. NIR light can penetrate through the fruit about 1/10-1/1,000,000 %. Therefore, very intensive light source and very sensitive sensor should be adopted to measure the transmitted light spectra of intact fruit. The ultimate purpose of this study was to develop a device to measure the transmitted light spectra of intact fruit such as apple, pear, peach, etc. With the transmittance-type VIS/NIR device, the feasibility of measurement of the SSC and titratable acidity in intact fruit cultivated in Korea was tested. The results are summarized as follows; A simple measurement device which can measure the transmitted light spectra of intact fruit was constructed with sample holder, two 500W-tungsten halogen lamps, a real-time spectrometer having a very sensitive CCD array sensor and optical fiber probe. With the device, it was possible to measure the transmitted light spectra of intact fruit such as apple, pear and peach. Main factors affecting the intensity of transmitted light spectra were the size of sample, the radiation intensity of light source and the integration time of the detector. Sample holder should be designed so that direct light leakage to the probe could be protected. Preprocessing method to the raw spectrum data significantly influenced the performance of the nondestructive measurement of SSC and titratable acidity of intact fruit. Representative results of PLS models in predicting the SSC of peach were SEP of 0.558 Brix% and R2 of 0.819, and those in predicting titratable acidity were SEP of 0.056% and R2 of 0.655.

• 한국식품과학회지
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• 제35권2호
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• pp.316-319
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• 2003

서울 등의 재래시장 및 대형 마켓 등지에서 판매되고 있는 상품김치 36종을 수집하여 pH, 산도, 색도 및 매운맛 특성을 조사하였다. 그 결과 숙성 정도가 pH $3.88{\sim}6.20$, 총산도 $0.28{\sim}1.13%$로 제조 즉시부터 어느 정도 과숙된 김치까지 다양하였다. 김치의 매운맛과 색도에 영향을 주는 요인을 고춧가루로 보고 고추의 매운맛 성분인 capsaicinoids 함량을 측정한 결과 $018{\sim}2.02\;mg%$를 나타내었고, ASTA값은 수분 함량을 고려하여 환산한 결과 가장 낮은 시료는 0.52, 가장 높은 시료는 4.1이었다. 즉 상품김치의 경우 규격화되어 있지 않고, 국내시장에서 발효단계, 매운맛 및 붉은색 정도가 다양하게 판매되고 있었다.

• 기술사
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• 제18권4호
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• pp.12-22
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• 1985

This investigation was attempted to determine changes in chlorophyll. Pheophytin content PH and titratable acidity during young redish Kim chi fermentation. Young redishes divied in to leaf and vein and fermented in dark room for 35 days at 10$^{\circ}C$ after pickling each group. Samples were collected at 5 days interval for the chemical analysis. The following results were obtained. 1. Chlorophyll content in young redish was decreased by decreasing PH during fermentation periods. Chlorophyll content decreased from 11.60mg/g to 7.62mg/g in leaf, from 0.48mg/g to 0.33mg/g in vein respectively during 35 days fermentation periods. In contrast to chlorophyll. pheophytin content increased as chlorophyll content decreased during the period. The ratio of chlorophyll a and b content in young redish about 3 : 1 in leaf and vein and decreased nearly the same ratio during fermentation periods. In case of pheophytin a and b it was increased without any relation with the ratio chlorophyll a and b. In generally, the optimum PH for eating was known 4.3 to 5.0. Young redish Kim chi was reached the optimun PH at 15 to 25 days of fermentation at 10$^{\circ}C$. At this periods. Chlorophyll content varied from 11.32mg/g to 9.30mg/g for leaf and from 0.43mg/g to 3.37mg/g for vein, respectively. 2. Titratable acidity(as lactic acid) was increased to 0.54% in leaf at 20 days fermentation period during Kim chi fermentation. and nearly unchanged until 30days. At the end of fermentation period the titratable acidity was about 0.30％. Titratable acidity was increased as decreasing pH. and the correlation coefficients was -0.92 in leaf and -0.77 in Vien. 3. Correlation between titratable acidity and chlorophll, pheophytin content was not significant statistically.

• Journal of Ginseng Research
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• 제20권3호
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• pp.299-306
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• 1996

This study was undertaken to examine the effects of fresh ginseng on the physicochemical and microbiological changes in dongchimi juice fermented under various conditions. The pH was somewhat lower in dongchimi juice added with 2.0% and 4.0% of fresh ginseng than that without ginseng, whereas the titratable acidity was higher in dongchimi juice with 2.0% and 4.0% of ginseng addition than the control. The addition of fresh ginseng to dongchimi preparation increased the numbers of total viable bacteria, lactic acid bacteria including Leuconostac mesenterotdes in dongchimi juice during fermentation. The changes in the counts of lactic acid bacteria were similar to those of total viable cells throughout the experiment except the initial stage of fermentation. However, the number of Leucosfastoc mesenternidgs decreased after the palatable stage. Key words : Panax ginseng C.A. Meyer, dongchlmi juice, pH, titratable acidity, microbiological changes.

• Preventive Nutrition and Food Science
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• 제7권4호
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• pp.397-404
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• 2002

Soybean curd residue (SCR) was fermented by lactic acid bacteria, Lactobacillus rhamnosus LS and Entercoccus faecium LL, isolated from SCR. The pH, titratable acidify and viable cell counts were determined from the fermented SCR to evaluate the lactic acid production and growth of lactic acid bacteria. Optimal amounts of pretense enzyme and glucose, and ideal fermentation time for SCR fermentation were estimated by response surface methodology (RSM). Raw SCR fermented by indigenous microorganisms had 0.78 % titratable acidity, The acid production in SCR fermented by L. rhamnosus LS was greatly enhanced by the addition of glucose and lactose. However only glucose increased acid production by Ent. faecium LL. The proof test of SCR fermentation demonstrated that similar results for titratable acidity, tyrosine content and viable cell counts to that predicted could be obtained by the at optimized fermentation conditions. In the presence of 0.029 % (w/w) pretense enzyme and 0.9% (w/w) glucose, the SCR fermented by Ent. faecium LL showed 1.07% (w/v) of titratable acidity, 1.02 mg% tyrosine content and 2$\times$10$^{9}$ (cfu/g) of viable cell counts. With the SCR fortified with 0.033% pretense enzyme and 1.7% glucose, L. rhamnosus LS showed 1.8% (w/v) of titratable acidity, 0.92 mg% of tyrosine content and 2$\times$10$^{9}$ (cfu/g) of viable cell counts.

• 생명과학회지
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• 제7권4호
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• pp.342-346
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• 1997

This experiment was carried out to clarify the effects of gibberellin(GA) aplication and bagging on repeening and quality in 'Delaware' grape berries. Treatments are 4 plots(2X2 factorial experiment); GA, GA+bagging, bagging and control. The clusters were dipped twice in 100 ppm GA with GA treatment : 10 days before and after the full bloom. The results obtained as follows: 1. GA treatment made the seedless grape berry reduced in the fresh weight but it hastened the ripening period about 2 weeks. 2. Total soluble solid(TSS), viscosity and pH value of berry juice increased with maturation. The concentration of TSS and viscosity were higher in GA treatment plot than GA non-treatment. 3. Berry-hardness, titratable acidity and alcohol inslouble solid(AIS) decreased with maturation. Expically berry-hardness and AIS decreased more greatly in GA non-treatment than GA treatment. 4. The concentration of anthocyanin increased with ripening but pectic substance didn't fluctuate nearly. These of anthocyanin and pectin were higher in GA non-treatment plot than GA treatment. 5. By analysis of factorial experiment GA treatment was highly significant with the $^{o}$Brix/Acidity ratio, juice viscosity and AIS, but high negatively, significant with berry-hardness and berry fresh weight. And it was significant with T S S and negatively, titratable acidity. Bagging was significant with $^{o}$Brix/Acidity ratio and AIS content, but negatively, titratable acidity. 6. Qualitative characters were high correlated with the $^{o}$Brix/Acidity ratio in simple correlation but direct effect by the path-coefficient analysis didn't coincide with simple correlation. The direct effect of pH was large and juice viscosity, the next. And that of berry-hardness was negligible but, AIS, small negatively.

• 한국식품조리과학회지
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• 제15권1호
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• pp.73-80
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• 1999

This study was carried out to investigate the effects of enzyme treatments on the functional properties of soy protein isolate (SPI) and to examine the quality attributes of soy yogurt prepared by different enzyme treatments, sweeteners and starter cultures. Enzyme treatment increased the solubility and emulsifying capacity of soy proteins, but decreased the emulsifying stability; the enzymatic activity of ${\alpha}$-chymotrypsin was higher than that of trypsin. Enzyme treatments decreased the pH of soy yogurts prepared by both culture methods, the culture of L. bulgaricus and S. thermophilus and the culture of L. bulgaricus and K. fragilis, but increased the titratable acidity, total numbers of lactic acid bacteria and yeast. Trypsin was more effective than ${\alpha}$-chymotrypsin in decreasing pH and increasing titratable acidity and total numbers of lactic acid bacteria and yeast. Fructose decreased the pH of soy yogurts more than sucrose in the culture of L. bulgaricus and S. thermophilus, and vice versa in the culture of L. bulgaricus and K. fragilis. Fructooligosaccharides were more effective in the culture of L. bulgaricus and K. fragilis than in the culture of L. bulgaricus and S. thermophilus in increasing the titratable acidity, total count of lactic acid bacteria and yeast. In sensory evaluation, soy yogurts containing trypsin treated SPI, fructose and fructooligosaccharides (75%:25%) were more acceptable than those containing untreated or trypsin treated SPI and fructose. This was because of more smooth and less sour, in which the values of pH, titratable acidity, microbial growth, and viscosity were in the range of commercial yogurts. Soy yogurts fermented by L. bulgaricus and K. fragilis showed more smooth mouthfeel than those fermented by L. bulgaricus and S. thermophilus.

• 한국식품과학회지
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• 제21권3호
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• pp.370-374
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• 1989

소금농도와 저장기간이 깍두기의 특성에 미치는 영향을 조사하기 위하여 깍두기의 관능적 특성, pH 및 적정산도를 측정하였으며 capillary gas chromatography로 비휘발성 유기산을 정성 및 정량 분석하여 비교하였다. 소금농도와 저장기간은 깍두기의 질긴 정도를 제외한 모든 관능적 특성에 영향을 주어 소금농도 2%군은 1%와 3%군에 비해 단단한 정도와 아삭아삭한 정도가 낮고 신맛이 강하였으며, 저장 8일군은 4일군보다 신맛과 이취는 강하나 단단한 정도와 아삭아삭한 정도는 낮았다. 저장기간이 증가할수록 pH는 감소하고 산도는 증가하였으며, 이 현상은 특히 2%군에서 두드러지게 나타났다. 깍두기에서 추출한 비휘발성 유기산으로는 lactic acid, succinic acid 및 citric acid가 대부분이었으며 소금농도 2%군은 다른 실험군들에 비해 유기산 생성량이 많았다. 이상의 결과에서 볼 때 소금농도 2%는 1%와 3%에 비해 깍두기의 연부를 억제하고 산의 생성을 감소시키는 숙성 억제효과가 낮았으며 깍두기의 신맛은 pH보다는 산도와 비휘발성 유기산 함량에 더 관련이 많았다.