• 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.

• 한국식품영양학회지
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• 제26권3호
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• pp.358-365
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• 2013

The study was conducted to investigate the condition for mixed fermentation of Rhodilola sachalinensis with red ginseng using Lactobacillus acidophillus 128 and the changes of physicochemical properties and antioxidant activities before and after the lactic acid fermentation was examined. In the single fermentation of Rhodiola sachalinensis extract, the pH and titratable acidity rarely changed, and the number of lactic acid bacteria decreased greatly. On the other hand, in the lactic acid fermentation of Rhodiola sachalinensis-red ginseng mixed extract of 50% red ginseng content, the pH decreased, whereas the titratable acidity and the number of lactic acid bacteria increased. The solid content of optimal mixed extract for lactic acid fermentation was 0.5%. Sugar content decreased during fermentation, but total phenolic compounds tended to increase during fermentation. The salidroside and p-tyrosol content of the initial Rhodiola sachalinensis-red ginseng mixed extract was 419.5 mg% and 60.1 mg%, respectively; after fermentation, the salidroside content after lactic acid fermentation decreased greatly to 81.8 mg%, and the amount of p-tyrosol increased greatly to 324.9 mg%. The DPPH scavenging activity of Rhodiola sachalinensis-red ginseng mixed fermentate was 78.1% at 0.1% concentration, showing a tendency to increase as compared to 50.3% of Rhodiola sachalinensis-red ginseng mixed extract before the fermentation (p<0.05); it was a higher antioxidant activity as compared to the single fermentation of Rhodiola sachalinensis or red ginseng.

• 한국식품과학회지
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• 제36권2호
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• pp.365-367
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• 2004

절임 배추의 저장 기간을 연장하기 위하여 배추를 절인 다음 전해산화수로 세척하고 저장하면서 품질 특성의 변화를 측정한 결과는 다음과 같았다. 즉 절임 배추를 전해산화수로 세척한 처리구가 대조구보다 낮은 pH를 보였으며, 저장 8일까지는 대조구에 비하여 낮은 pH를 나타내었다. 적정산도는 저장기간 동안 0.11-0.15%로 큰 변화를 나타내지 않았으며, 대도구와 처리구간에도 큰 차이가 없었다. 절임 배추를 전해산화수로 세척한 직후에는 대조구에 비하여 총균수가 $10^3\;CFU/mL$ 정도 낮았으나 처리구의 총균수는 저장 6일에 대조구와 비슷하였다. 유산균수도 세척 직후에는 처리구가 대조구보다 낮았으며, 저장 4일에는 대조구와 처리구의 차이가 가장 현저하였다. 저장 2일까지는 국물의 밝은 정도(L)에 있어서 대조구와 처리구간에 차이가 없었으나 그 이후에는 처리구가 대조구보다 높은 값을 나타내었다.

• Journal of Applied Biological Chemistry
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• 제53권1호
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• pp.51-55
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• 2010

김치에서로부터 배 파쇄물에서 생육과 산 생성이 우수한 유산균을 선발하였다. 선발된 균주는 Ln. mesenteroides로 동정되었으며, 국립농업과학원 농업유전자원센터에 KACC 91495P로 기탁하였다. KACC 91495P 균주를 배 파쇄물에 접종한 후 pH, 적정산도, 생균수의 변화를 경시적으로 분석하였다. 배양액의 pH는 배양 9시간 이후 pH 4.05로 급격히 감소한 후 배양 18시간에 pH 3.86까지 완만하게 감소하였다. 적정산도는 배양 초기부터 15시간까지 지속적으로 증가하여 1.09% 수준에서 평형을 이루었다. 생균수는 접종 후 9시간까지 급격히 증가하고 그 이후 완만하게 증가하여 배양 18시간에는 $2.9{\times}10^9\;CFU/g$까지 증가하였다. 유기산 농도는 배양시간에 비례하여 증가하여 18시간 배양 후 젖산이 0.213%, 초산이 0.259%, 사과산이 0.217%로 분석되었다. 또한 배 발효액의 총 폴리페놀 함량은 9시간 배양 후 $134\;{\mu}g$ tannic acid/mL에서 $185\;{\mu}g$ tannic acid/mL로 약 40% 증가하였으며 따라서 DPPH radical 소거활성도 향상되었다. 또한 $4^{\circ}C$에서 KACC 91495P 균주에 의한 배 발효물은 약 2주일의 저장기간 동안 pH, 적정산도, 총균수의 변화는 미미하였다.

• Journal of Microbiology
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• 제42권2호
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• pp.133-138
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• 2004

This study was aimed to determine the accumulation of free fatty acid by mesophilic lactic acid bac-teria (Lactococcus lactis subsp. lactis 1471, Lactococcus lactis subsp. cremoris 1000 and Lactobacillus casei 111) in cold-stored milk. According to the results, all cold-stored milks had higher acid degree val-ues than those of fresh milk. This phenomenon showed that a slight increase occurred in the accumulation of free fatty acids as a result of spontaneous lipolysis during cold storage. All lactic acid bacteria showed good performance in production of titratable acidity, which increased during fermentation of the milk (fresh and stored milks). Moreover, as the storage time was prolonged, more free fatty acid accumulation was obtained from the fermentation of the cold-stored milk by the investigated lactic acid bacteria. The control milk, which was without lactic acid bacteria, showed no change in the accumulation of free fatty acid during fermentation. From this result, it can be suggested that longer cold-storage time can induce higher free fatty acid accumulation in milk by lactic acid bacteria.

• 동아시아식생활학회지
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• 제4권2호
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• pp.39-44
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• 1994

To prepare the basic information for the fermentation of high quality persimmon vinegar in the farm. the quality of the complex fermented persimmon vinegar(CFPV) was compared to that of naturally fermented persimmon vinegar (NFPV). The titratable acidity of the CFPV was 3% which was the half concentration of the NFPV. The content of total free sugar by HPLC was 6% in CFPV and NFPV was 5%. Organic acid compositions in persimmon vinegar were oxalic acid, malic acid, lactic acid, citric acid, succinic acid and glutaric acid in addition to acetic acid. Total content of the organic acids in NFPV was higer than in CFPV. Especially, the content of latic acid in NFPV was very higher than that of CFPV. the flavour, color and taste of persimmon fruit itself in CFPV were stronger than those in NFPV.

• 한국식품저장유통학회지
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• 제19권6호
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• pp.933-938
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• 2012

막걸리 양조시 품질변화 방지를 목적으로 젖산 첨가량에 따른 주모의 pH, 총산, ethanol 및 미생물 균수를 측정하고, 젖산 농도에 따른 주모별 막걸리를 제조하여 이화학적 및 관능평가 등 품질특성을 확인한 결과는 다음과 같다. 젖산 농도에 따른 주모의 pH는 젖산 0.5% 이상 첨가 시료구가 pH 3.31~3.33으로 젖산 무첨가구와 0.3% 첨가 시료구의 pH 3.52, 3.56에 비해 낮았다. 총산 함량은 젖산 무첨가구와 젖산 0.3%첨가 주모가 0.56%와 0.54%로 높게 나타났고, 0.5%첨가 주모는 0.51%로 가장 낮은 함량을 보였다. Ethanol 함량은 젖산을 첨가하지 않은 주모와 젖산을 첨가한 주모 모두 유의적 차이를 보이지 않았다. 주모의 미생물의 균수를 측정한 결과는 세균 및 젖산균은 젖산 첨가량이 증가할수록 감소하였고, 효모는 젖산을 첨가하지 않은 대조구와 비교해 0.3~0.5% 첨가구는 증가하였으나 0.7~1.0% 첨가구는 감소하였다. 젖산 첨가량에 따른 주모로 담금한 막걸리의 pH 및 총산은 0.5% 이상 첨가구에서 발효기간 동안 안정된 값을 보여 주모의 안전 제조에 적합한 조건을 보였다. 유기산은 lactic acid의 함량이 가장 높았고, succinic acid, tartaric acid, citric acid 및 acetic acid가 검출되었다. acetic acid는 젖산을 첨가하지 않은 시료구의 경우 390.88 mg%로 함량이 가장 높았고 젖산 첨가량이 증가할수록 낮았으며, 1.0% 첨가 시료구의 경우 검출되지 않았다. Ethanol 함량은 시료구별 차이를 보이지 않았고, 관능평가 결과 젖산 0.5%이상 첨가구부터 향, 맛 및 종합기호도에서 선호도가 좋은 결과를 보였다. 이러한 결과를 볼 때 젖산을 첨가하지 않은 주모에 비해 젖산을 첨가하여 주모를 제조할 경우 막걸리의 품질이 더 향상될 것으로 판단되며, 젖산량은 주모 중량대비 0.5%첨가가 적당할 것으로 사료된다.

• 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.

• Journal of Microbiology and Biotechnology
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• 제23권1호
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• pp.76-84
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• 2013

A polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique followed by sequencing of the 16S rDNA fragments eluted from the bands of interest on denaturing gradient gels was used to monitor changes in the bacterial microflora of two commercial kimchi, salted cabbage, and ingredient mix samples during 30 days of fermentation at $4^{\circ}C$ and $10^{\circ}C$. Leuconostoc (Lc.) was the dominant lactic acid bacteria (LAB) over Lactobacillus (Lb.) species at $4^{\circ}C$. Weissella confusa was detected in the ingredient mix and also in kimchi samples throughout fermentation in both samples at $4^{\circ}C$ and $10^{\circ}C$. Lc. gelidum was detected as the dominant LAB at $4^{\circ}C$ in both samples. The temperature affected the LAB profile of kimchi by varing the pH, which was primarily caused by the temperature-dependent competition among different LAB species in kimchi. At $4^{\circ}C$, the sample variations in pH and titratable acidity were more conspicuous owing to the delayed growth of LAB. Temperature affected only initial decreases in pH and initial increases in viable cell counts, but affected both the initial increases and final values of titratable acidity. The initial microflora in the kimchi sample was probably determined by the microflora of the ingredient mix, not by that of the salted cabbage. The microbial distributions in the samples used in this study resembled across the different kimchi samples and the different fermentation temperatures as the numbers of LAB increased and titratable acidity decreased.

• Journal of Dairy Science and Biotechnology
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• 제35권4호
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• pp.249-254
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• 2017

The purpose of this study was to investigate the acid tolerance, bile acid tolerance, and fermentation activity of lactic acid bacteria isolated from Kimchi in the presence of hydrolysates of whey protein concentrate. Kimchi isolates DK109, DK119, DK121, DK128, DK211, DK212, and DK215, which were identified as Lactobacillus sp., and L. casei DK128 showed the highest acid and bile acid tolerance. To produce whey hydrolysates, enzymes were added to a 10% (w/v) whey protein concentrate (WPC) solution at 1:50 (w/v, protein). The viabilities of the DK strains were determined in the presence of low pH and bile salts. Then, yogurt was produced via fermentation with L. casei DK128, an isolate from Kimchi, in the presence of the following additives: CPP, WPC, and WPC hydrolysates (WPCH) generated by alcalase (A) or neutrase (N). The produced yogurts were subjected to various analyses, including viable cell counts (CFU/mL), pH, titratable activity, and sensory testing. After 8 h of fermentation, the pH and titratable activity values of all test samples were 4.2 and 0.9, respectively. The viable counts of LAB were $3.49{\times}10^8$, $5.72{\times}10^8$, $7.01{\times}10^8$, and $6.97{\times}10^8$, for the Control, CPP, A, and N samples, respectively. These results suggest that whey proteins have potential as dietary supplements in functional foods and that WPCH could be used in yogurt as a low-cost alternative to CPP.