• Korean Journal of Food Science and Technology
• /
• v.28 no.1
• /
• pp.117-121
• /
• 1996

In order to find the reason for souring of Hansan sogokju (Korean traditional rice wine), microbial distribution, pH change and organic acids were analysed. Besides 161 mM of lactic acid as a major organic acid, small amount of acetic acid, malic acid, propionic acid were found in sogokju. Four different microbial strains were identified from the sogokju. These are two strains of Lactobacillus spp., Bacillus sp. and yeast. The pH of sogokju was changed from 4.01 to 3.29 during 18 days storage at $30^{\circ}C$. Amount of total acidity increased from 9 to 34.86 at the same condition. Notable change in the soured sogokju was an increase of the lactic acid (from 161 mM to 192 mM). So, we could assume that it was soured by an additional production of lactic acid by lactic acid bacteria during storage. The shelf life of sogokju was 41 days below $15^{\circ}C$ degree because this temperature was hard condition for the growth of Lactobacillus spp., causative bacteria responsible for additional lactic acid production.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.22 no.2
• /
• pp.165-174
• /
• 1993

This work was conducted to study the use of L. acidophilus, which exists in humun intestine for the fermentation of Chinese cabbage kimchi. The changes in vitamins, the number of microflora and sensory quality were observed during fermentation after the microflora which was not related to kimchi fermentation was eliminated by treatment with ozone water or ozone gas. The growth rate of L. acidophilus in the cabbage juice was higher than that in MRS broth. The growth of L. acidophilus was slightly promoted by adding 1~2% hot pepper powder while that was inhibited by ginger and garlic. Therefore, it was shown that the regulation of fermentation was possible by addition of spices. The result of treating spice with ozone gas and ozone water 6mg/L/sec for 1 hour was that the survival ratio of total microflora was 6~20%. When L. acidophilus was added to materials after ozone treatment, the fermentation rate was improved and the polysaccharides in the cell wall were used when the usable free sugar was all consumed. The contents of vitamin B$_1$ and C in the ozone treated kimchi was higher than in the control.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.11
• /
• pp.1829-1836
• /
• 2013

This study is carried out to investigate the physicochemical characteristics, microbial population, and sensory characteristics during fermentation of Korean traditional rice wine with addition of glutinous rice. The fed-batch fermentation of rice was performed by Nuruk and yeast for 10 days at $28^{\circ}C$ in a water bath. The four fermentation batches included 0, 10, 15 and 20% of glutinous rice based on the total rice contents. The growth of total viable cells, lactic acid bacteria (LAB), and yeasts were similar among the four batches during the fermentation period. The population for total viable cells and LAB were increased for the first 3 days, and decreased slowly until 10 days. The number of yeast cells was rapidly decreased after day 6, when the alcohol content reached about 15% for all the fermentation batches. Physicochemical characteristics, such as pH, total acidity, and reducing sugars, were not different with the increase of additional glutinous rice contents. The ethanol production was higher in Korean traditional rice wine from non-glutinous rice (17.1%) than ones from glutinous rice (15.8~16.7%). For the sensory evaluations, Korean traditional rice wine with 15% glutinous rice was highly preferred due to the highest sweetness.

• Microbiology and Biotechnology Letters
• /
• v.39 no.1
• /
• pp.56-62
• /
• 2011

We investigated quality characteristics of Seoktanju (one of the Korean traditional rice wine) which was fermented using five kinds of Korean commercial Nuruks. The purpose of this study was to research what effects on the quality of Seoktanju by using different Nuruks. We analyzed general component such as each mash's temperature change patterns, pH, titrable acidities, reducing sugar contents, volatile acids, and sugar contents during fermentation periods and studied sensory evaluation of produced Seoktanju (10 days). On the whole, temperature change patterns in the each mashes were depend on room temperature. All Seoktanju's pH was reduced rapidly up to three days after first mashing (pH 3.13-3.57) and after that was increased gradually. The end of fermentation pH was pH 3.6-4.05. Mostly, acidities were indicated high(0.59%) and Nuruk-B was showed highest acid value. These results seems to be different as occasion organic acids producing activity depend on the number of yeast, material contents, optimal temperature in the each mashes by fungi and lactic acid bacteria in Nuruks. In reducing sugar contents and sugar contents, Nuruk-C treatment were showed the highest value with 5.36%, $23^{\circ}brix$, respectively and alcohol content was lowest with 8.6%. In the five kinds of reproduced Seoktanju, alcohol content was the highest in the treated Nuruk-A group. Volatile acid value was the highest with 132.6~263.7 ppm at the 3 day after first mashing day but as the fermentation time goes on, it was reduced sharply by 5.25~5.94 ppm. Sensory evaluation was performed with 5 point scale, the Seoktanju using Nuruk-D was presented by 4 point, while Nuruk-A was presented lowest by 2.77 point on overall acceptability.

• Food Science and Preservation
• /
• v.20 no.6
• /
• pp.854-862
• /
• 2013

We examined the quality characteristics and functionalities of Korean and Japanese spring Baechu cabbages and the kimchi prepared with them. To study the physiochemical properties of the cabbages and the kimchis, we measured their water content, pH, acidity, microbial counts, and springiness. On the third week of the kimchi fermentation at $5^{\circ}C$, their sensory properties and in vitro DPPH radical scavenging and anticancer activities using AGS human gastric cancer cells were determined. The Japanese Baechu contained 97.1% water, and the Korean Baechu, 92.4%. The comparison of the textures of the raw Baechu and the brined Baechu showed that the Korean Baechu had higher springiness scores than the Japanese Baechu. After four-week fermentation, the springiness score of the kimchi with Korean Baechu was 53.5%, significantly higher than the 41.4% of the kimchi with Japanese Baechu. The kimchi prepared with Korean Baechu had a low total bacterial count but higher Lactobacillus sp. and Leuconostoc sp. counts than the kimchi with Japanese Baechu. The kimchi prepared with Korean Baechu had the highest overall acceptability score in the sensory evaluation test. The DPPH radical scavenging activity of the kimchi with Korean Baechu was 83.2%, and that of the kimchi with Japanese Baechu, 46.1%. When the AGS human gastric cancer cells were treated with the kimchis, the kimchi prepared with Korean Baechu showed a 45% cancer cell growth inhibition rate, and the kimchi with Japanese Baechu, 26%, at 1 mg/mL of methanol extracts. At the 2 mg/mL concentration, the kimchis with Korean Baechu and Japanese Baechu showed 97% and 74% inhibition, respectively. The Korean Baechu showed better quality than the Japanese Baechu, and the kimchi prepared with the Korean Baechu showed better kimchi quality and functionality than the Japanese Baechu.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.33 no.3
• /
• pp.576-581
• /
• 2004

Foxtail Millet Yakju were treated with heat ($65^{\circ}C$/15 min) or high hydrostatic pressure ($25^{\circ}C$ (RT) and $65^{\circ}C$ (HT)/400 MPa/10 min), and stored for 64 days at l$0^{\circ}C$, $25^{\circ}C$ and 37$^{\circ}C$. Changes in microbial counts, enzyme activity and quality of Yakju during storage were measured. Total viable cells were about 10$^2$ CFU/mL, and remained almost constant during storage at l$0^{\circ}C$ and $25^{\circ}C$, while decreased significantly at 37$^{\circ}C$, and undetected after 55 days of storage in heat- and pressure(RT)-treated, but after 25 days in pressure(HT)-treated Yakju. Lactic acid bacteria and yeast in heat- and pressure-treated Yakju were not detected during storage. The relative activities of a -amylase in heat- and pressure(RT)-treated were more than 100%, while those in pressure(HT)-treated were less than 40% during storage of 64 days at l$0^{\circ}C$. However, at $25^{\circ}C$ and 37$^{\circ}C$ the relative activities in untreated and pressure(RT)-treated were decreased greatly and then reached at the point of the activities of heat- and pressure(HT)-treated. The relative activities of glucoamylase in untreated and pressure(RT)-treated were decreased as the increase of the storage temperature during storage, while those in heat- and pressure(HT)-treated increased slightly as the increase of storage period at 1$0^{\circ}C$ and $25^{\circ}C$, and had no change at 37$^{\circ}C$. pH in heat- and pressure-treated had almost no change. Turbidity and reducing sugar in heat- and pressure-treated increased as the increase of storage temperature during storage.

• Food Science of Animal Resources
• /
• v.29 no.4
• /
• pp.437-444
• /
• 2009

${\gamma}-Aminobutyric$ acid (GABA) producing lactic acid bacteria, Lactobacillus acidophilus RMK567 was cultivated in 50 L of sterilized MRS broth using a fermenter at $40^{\circ}C$ for 24 h. The cell number was increased to $10.04{\pm}0.13$ Log CFU/mL with a growth rate constant (k) of 0.454 generation/h and a generation time (g) of 2.303 h after a lapse of a lag phase (L) of 5.16 h. A total of 487 g of cell paste with 40.5% moisture was harvested with viable cell number of 12.48 Log CFU/g cell paste. The cell pastes after preparation with glycerol, glucose, and polydextrose as cryo-protectants were lyophilized under a vacuum of 84 m torr. A total of 408 g of freeze dried (FD) cell powders were mixed with a commercial strain of Streptococcus thermophilus to prepare of three types FD starter cultures with the viable cell numbers of 12.42 (FDA-GY), 12.60 (FDBGG) and 12.91 (FDC-GP) Log CFU/g. During preservation the FD cultures at -$18^{\circ}C$, the cell viability of the FD starter cultures were rapidly dropped to below 3.24% of the day of storage. No significant difference was found in the cell viabilities among three types of FD starters cultures, but significant difference (p<0.01) was found in storage periods. Yoghurts fermented through FD starter culture of L. acidophilus RMK567 were determined to contain $155.16{\pm}8.53$ ppm, $243.82{\pm}4.27$ ppm, and $198.64{\pm}23.46$ ppm of GABA, respectively. This study shows that GABA production activity of L. acidophilus RMK567 is not affected during the freeze drying process and would be available for commercial production of yoghurt containing high GABA content.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.8
• /
• pp.996-1002
• /
• 2009

This study was carried out to improve quality and increase anticancer effect of baechu kimchi by changing various kinds of salt. The baechu cabbages were brined with purified salt (P), natural sea salt (NS), natural sea salt without bittern (NS-B) or baked (Guwun) salt (G) and mixed with other ingredients. Thereafter, the kimchis were fermented for 7 days at $15^{\circ}C$. The changes in pH and acidity of the P and G kimchis were slower than those of NS and NS-B kimchis. NS-B and G kimchis promoted the growth of Leuconostoc sp.; however, it inhibited the growth of Lactobacillus sp. when compared with P and NS brined kimchis. The sensory evaluation results indicated that NS-B and G kimchis were better than P and NS kimchi in taste, color and overall acceptability. Rheological property of texture (cutting strength) of NS-B and G brined kimchis was also much better. Anticancer effects of the kimchi juices and methanol extracts were investigated on AGS human gastric adenocarcinoma cells and HT-29 human colon carcinoma cells by MTT assay. NS-B and G kimchis significantly retarded the growth of both cancer cells compared to P and NS kimchis. From these results, kind of salt is very important when kimchi is prepared. It proved that removing bittern from natural sea salt is good ancient tradition when brining the cabbage. Using the baked salt is also a better method to improve the quality and anticancer effect of kimchi.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.19 no.4
• /
• pp.355-362
• /
• 1999

This experiment was conducted to evaluated the effect of maturity at harvest and wrap colors on the quality of round baled rye(Secal cereale L.) silage at the forage experimental field, Grassland and Forage Crops Division, National Livestock Research Institute, Suwon in 1998. The experiment was consist of split-plot design with three repications. The main plots were three different harvesting stages : boot, heading, and flowering stages, the subplots were wrap colors : white, black, and light green color. Acid detergent fiber(ADF) and neutral detergent fiber(NDF) of rye silage were increased with delayed harvesting date, but there were no significant differdence among wrap colors. However, average in vitro dry matter digestibility (IVDMD) of rye silage with white color wrap tended to have higher than those of other colors. The silage pH of heading stage was highest (5.12), and that of flowering stage was lowest (4.57) in different harvest stages. Among tested wrap colors, white color wrap resulted on lowest pH than others (p<0.05), but there were no significant difference between black and light green color. Dry matter (DM) content of rye silage were increased as harvest stage progressed (p<0.05). However, DM content of white color was highest among warp colors, but there was signifiant difference (p<0.05). Ammonia-N content of silage harvested at boot stage was the highest in harvest stage, but there was no difference between heading and flowering stages. Among wrap colors tested, ammonia-N content of black color was highest, but there was no significant difference. The number of lactic acid bacteria of white colors was highest in different colors, and that of flowering stage was highest among harvest stage. Acetic and butyric acid contents were decreased as harvest stage progressed, and lactic acid was increased from 6.33 to 7.98%. However, wrap colors did not influence lactic acid concentration. Among different wrap colors, outside temperature of rye silage was affected by air temperature, but effect of inside temperature was minimal. Black color wrap increased inside temperature by $3{\sim}5^{\circ}C$. The results of this study indicate that rye should be harvested for round bale silage after heading stage. The quality of rye silage wrapped white and light green color will increase slightly.

• Journal of Animal Science and Technology
• /
• v.48 no.4
• /
• pp.611-622
• /
• 2006

Fatty acid compositions and physicochemical properties of feta cheese made from bovine milk were studied. Nutritional compositions of feta cheese were fat 22.79%, protein 10.57% with moisture content of 59.87%. The log cfu/g of lactic acid bacteria in bovine feta cheese decreased from 10.25 to 7.95 and pH also changed from pH 6.22 to pH 5.55 during storage at 4℃ for 14 d aging. The color of feta cheese turned into more whitish (L-value, 100.1) with a red (a-value, 4.6) and gray (b-value,－4.1) color after 14day's aging. For the texture profile analysis of bovine feta cheese, resilience was increased significantly (p<0.01) throughout the aging periods and adhesiveness was rapidly increased right after progressing of aging at both temperatures, but no difference was found between the aging periods. Hardness, fracturability, gumminess and chewiness were gradually increased at 0℃, but no statistical significances were found. Springiness and cohesiveness were not changed at both temperatures. In organoleptic evaluations, organoleptic intensities in sweetness, milky taste and saltiness were significantly enhanced over those of the control cheese at the level of p<0.01, and masticatory texture at p<0.05 with the progress of aging to 14d. Organoleptic preferences were significantly (p<0.01) enhanced except smell, color, mouth feel, and masticatory texture with the aging. In the fatty acid compositions of feta cheese analyzed by gas chromatography, the content of SFA (52.61%) was slight higher than that of USFA (47.39%) composed with MUFA (28.98%) and PUFA (18.41%). Among the nutritionally important fatty acids; ω6 (9.27%) and ω3 (0.55%) fatty acids, CLA (0.12%), arachidonic acid (0.19%) and DHA (0.12%) were also found in bovine feta cheese.