• Korean Journal of Microbiology
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• v.6 no.2
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• pp.41-53
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• 1968

Studies on the carbohydrate metabolism of yeast as influenced by gamma-irradiation from cobalt-60 have been carried, then the mechanisms of radiation effect on respiration and fermentation were discussed under considerations of permeable changes of irradiated cell membrane. The cells of baker's yeast (Saccharomyces cerevisiae) which had been gamma-irradiated of 240 k.r. doses for an hour, then were put into aerobic oxidation and anaerobic fermentation without substrate. Total and fractionated carbohydrates of irradiated yeast cells were determined by calorimetric method with anthrone and orcinol reagents, the amounts of total carbohydrate, trehalose, RNA-ribose, PCA-soluble glycogen, alkali-soluble glycogen, acetic acid-soluble glycogen, mannan and glucan were determined according to the course of aerobic oxidation and anaerobic fermentation. It is found that the carbohydrates of irradiated cells leak out and amount of the losses teaches eleven times more than that of control, the volume of losses are seems to be replaced by water, it can be suggested the damage of gamma-irradiation occurs in the site of passive transport of cell membrane. The endogeneous aerobic respiration of irradiated cells are increased much more than control, the synthesis of reserve glycogen, glucan and RNA-ribose promoted much more than control. The anaerobic fermentation of irradiated cells are also increased than that of control, but the breakdown of carbohydrate is less than endogeneous respiration of irradiated cells. The synthetic rate is also less than that of aerobic oxidation. In irradiated yeast cells, trehalose is revealed to be primary substrate for endogeneous carbohydrate metabolism, so it is proved that the enzymic patterns are not changed but the activities of enzymes relating endogeneous respiration and autofermentation is activated. It is to be considerable to distiguish endogeneous respiration and autofermentation from exogeneous respiration and fermentation on irradiation, for membrane permeability changes and loses out carbohydrate by ionizing radiation.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.11
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• pp.1763-1775
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• 2019

Objective: The influence of konjac gel level on fermentation process and product qualities were assessed to evaluate the feasibility of using it as fat analog in Northeastern Thai fermented sausage (Sai Krok E-san). Methods: Five treatments of fermented sausages were formulated by replacing pork backfat with 0%, 7.5%, 22.5%, and 30% konjac gel. The changes in lactic acid bacteria (LAB) and important physicochemical properties of samples were assessed during 3 days of fermentation. After the end of fermentation at day 3, water activity ($a_w$), instrumental texture, color, microbial counts, and sensory evaluation were compared. The best product formulation using konjac for replacing pork back fat were selected and used to compare proximate composition and energy value with control sample (30% pork backfat). Results: An increase in konjac gel resulted in higher values of LAB, total acidity, and proteolysis index with lower pH and lipid oxidation during 3 days of product fermentation (p<0.05). It was noted that larger weight loss and product shrinkage during fermentation was observed with higher levels of konjac gel (p<0.05). The resulting sausage at day 3 with 15% to 30% konjac gel exhibited higher hardness, cohesiveness, gumminess, springiness, and chewiness than control (p<0.05). The external color of samples with 22.5% to 30% konjac gel were redder than others (p<0.05). Mold, Salmonella spp., Staphylococcus aureus, and Escherichia coli in all finished products were lower than detectable levels. Product with 15% konjac gel had the highest scores of sourness linking and overall acceptability (p<0.05). Conclusion: The product with 15% of konjac gel was the optimum formulation for replacing pork backfat. It had higher sensorial scores of sourness and overall acceptability than control with less negative impact on external appearance (product shrinkage) and weight loss. Moreover, it provided 46% fat reduction and 32% energy reduction than control.

• Preventive Nutrition and Food Science
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• v.10 no.1
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• pp.22-28
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• 2005

Physicochemical properties and sensory characteristics of kakdugi prepared with red pepper powder gamma-irradiated up to 7 kGy were determined during fermentation at 5℃. The overall fermentation patterns between kakdugies with irradiated and nonirradiated red pepper powder were similar. Kakdugi prepared with irradiated red pepper powder required one week longer time for optimal ripening compared to the kakdugi control. Irradiated red pepper powder did not affect the hardness and fracturability of kakdugi during fermentation. Kakdugi prepared with irradiated red pepper powder maintained a redder color than the kakdugi control. No significant differences were observed in taste, odor, texture, and overall acceptability (p<0.05) except for color. It can be concluded that irradiation of red pepper powder, up to 7 kGy, did not affect the quality of kakdugi with regard to physicochemical and sensory characteristics during fermentation. Moreover, irradiated red pepper powder was better for maintaining the red color and delaying optimum ripening time of kakdugi fermentation.

• Korean Journal of Food Science and Technology
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• v.36 no.1
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• pp.92-96
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• 2004

Chitin and its derivatives (chitosan and glucosamine) were studied for their effects on ethanol production using YPD (yeast extract 10%, peptone 20%, glucose 20%, agar 20%) medium. All chitin derivatives, particularly chitin, increased ethanol production compared with control. In non-steamed alcohol fermentation of tapioca, addition of 0.9% chitin yielded higher ethanol production (13.6%) with lower acetaldehyde (21.91 ppm) and methanol (65.49 ppm) contents than those (12.7%, 35.05 ppm, 84.31 ppm, respectively) of control after fermentation for 120 hr at $30^{\circ}C$. Results indicate that chitin can be used to increase ethanol production in non-steamed alcohol fermentation of tapioca.

• Korean Journal of Human Ecology
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• v.5 no.1
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• pp.85-93
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• 2002

This study was conducted to examine the effects of chitosan on the changes in physicochemical characteristics and hardness during Kimchi fermentation. The Kimchi samples were stored for 8 days at $20{\pm}l^{\circ}C$. The results were as follows : The pH value was decreased in order of Kimchi treated with 0.05% of 5% chitosan solution(chitosan 0.05%), Kimchi treated with 0.025% of 5% chitosan solution(chitisan 0.025%), Kimchi treated with 0.01% of 5% chitosan solution(chitosan 0.01%) and control, and the total acidity was increased in the opposed order. Volatile acid was increased like the total acidity, it was decreased after 6 days during fermentation, reducing sugar contents of Kimchi samples were decreased gradually. The ascorbic acid contents of Kimchi were increased rapidly in the early stage of fermentation and decreased in the late stage. Properties of hardness of Kimchi measured instrumentally were higher in the Kimchi treated with chitosan than control throughout the fermentation period.

• Food Science and Preservation
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• v.17 no.2
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• pp.214-222
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• 2010

The fermentation and quality characteristics of kimchi prepared using various types of maesil, including freshly sliced maesil (FSM), freshly ground maesil (FGM),and dried maesil powder (MP), were investigated during 25-day fermentation at 10C. The pH value decreased rapidly in the control fermentation but only slowly in maesil-supplemented kimchi. Titratable acidity values changed in the same manner. The addition of maesil significantly inhibited the growth of total aerobes, and lactic acid bacteria during fermentation over 10 days. The color (L, a, and b values) of kimchi did not differ between control and maesil-supplemented kimchi samples regardless of maesil type or concentration. Kimchi hardness did not initially differ among the various samples but decreased during fermentation. However, the hardness of maesil-supplemented kimchi was higher than that of control samples. Thus, kimchi supplemented with either 6% (w/w) MP or 6% (w/w) FGM maintained optimal hardness during fermentation. The antioxidant activity of kimchi was increased in a dose-dependent manner by addition of maesil. Kimchi supplemented with 6% (w/w) FGM showed the highest antioxidant activity. The sensory qualities (taste, flavor, color, and overall acceptability) of FSM-supplemented kimchi were better than those of control samples.

• Food Science and Preservation
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• v.10 no.3
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• pp.354-359
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• 2003

This study was conducted to investigate the fermentation characteristics of kimchi treated with different methods of water extracts of powdered green tea(GT). Four different kimchis, the SB-kimchi(control) which was not treatment of the extracts, SG-kimchi prepared with Chinese cabbage(CC) salted in 1％ GT containing 10％ brine, DG-kimchi prepared with CC dipped in 1％ GT for 30 min after salting, MS-kimchi prepared with the salted CC mixed with 1％ GT containing seasonings. All kimchis was fermented at 10$^{\circ}C$. The pH of treated-kimchis were maintained higher than those of control products during fermentation, but it showed no big difference between each treated groups. Total microbe of SB-kimchi(6.27-9.37 cfu/mL) was higher than those of GT-treated kimchi(5.17-9.20) during fermentation. The ratio of lactic acid bacteria against total microbe was higher than the treated kimchis. Total polyphenol content of kimchi was 52.75 mg％ in DG-kimchi, 47.71 mg％ in MS-kimchi, 44.89 mg％ in SG-kimchi, 30.70 mg％ in SB-kimchi on the 5th days of fermentation. Scores of crispy taste of SG- and DG-kimchi on the 5th days of fermentation was 4.03 and 4.01 points, respectively which was higher than control products. Scores of fishy and hot taste of GT-treated kimchi were lower than those of control products during all fermentation periods.

• Food Science and Preservation
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• v.10 no.3
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• pp.345-359
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• 2003

This study was conducted to investigate the fermentation characteristics of kimchi treated with different methods of water extracts of powdered green tea(GT). Four different kimchis, the SB-kimchi(control) which was not treatment of the extracts, SG-kimchi prepared with Chinese cabbage(CC) salted in 1％ GT containing 10％ brine, DG-kimchi prepared with CC dipped in 1％ GT for 30 min after salting, MS-kimchi prepared with the salted CC mixed with 1％ GT containing seasonings. All kimchis was fermented at 10$^{\circ}C$. The pH of treated-kimchis were maintained higher than those of control products during fermentation, but it showed no big difference between each treated groups. Total microbe of SB-kimchi(6.27-9.37 cfu/mL) was higher than those of GT-treated kimchi(5.17-9.20) during fermentation. The ratio of lactic acid bacteria against total microbe was higher than the treated kimchis. Total polyphenol content of kimchi was 52.75 mg％ in DG-kimchi, 47.71 mg％ in MS-kimchi, 44.89 mg％ in SG-kimchi, 30.70 mg％ in SB-kimchi on the 5th days of fermentation. Scores of crispy taste of SG- and DG-kimchi on the 5th days of fermentation was 4.03 and 4.01 points, respectively which was higher than control products. Scores of fishy and hot taste of GT-treated kimchi were lower than those of control products during all fermentation periods.

• Food Science and Preservation
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• v.19 no.5
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• pp.659-664
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• 2012

The fermentation and quality characteristics of Cheonggukjang with Chinese cabbage, which is produced as a by-product in the kimchi industry, were investigated. Cheonggukjang was prepared with cooked soybean without Chinese cabbage (control), with 10% Chinese cabbage (A10), and with 20% Chinese cabbage (A20), respectively. The A10 and A20 pH values did not show a significant difference compared with the control during fermentation for 72 h. The total aerobes of the Cheonggukjangs reached 8.65 (control), 8.73 (A10), and 9.11 (A20) log CFU/mL after fermentation for 72 h at $37^{\circ}C$, respectively. The numbers of lactic acid bacteria were found to be 5.62 (A10) and 5.87 (A20) log CFU/mL during fermentation for 72 h at $37^{\circ}C$, but lactic acid bacteria were not detected in the control. The amino nitrogen and viscous substance contents of A10 and A20 were lower than those of the control. The total polyphenol contents and DPPH radical scavenging abilities of the tested Cheonggukjang were increased by fermentation. The increasing ratio of polyphenol and the DPPH radical scavenging ability of A10 were higher than those of the control and of A20. The sensory quality of A10 was higher than that of the control and of A20 in taste, color, and overall acceptability.

• Food Science and Preservation
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• v.14 no.4
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• pp.356-363
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• 2007

This study investigated the effects of a Hwangki (Astragalus membranaceus) extract on the quality of Chungkukjang fermented by Bacillus subtilis KCCM 12148, at 30, 40, and $50^{\circ}C$, for 4 days. Changes in moisture contents, protein levels, pH values, ammonia-type nitrogen levels, color, angiotensin-converting-enzyme (ACE) inhibition rates, and fibrinolytic activities, were all determined. For both control and test, the moisture contents decreased gradually with time and the protein levels increased slightly. The pH values fell at the beginning of fermentation and then rose. The content of ammonia-type nitrogen was higher in Hwangki with Chungkukjang than in control, until 24 hr after fermentation commenced. After that time, the content of ammonia-type nitrogen control was higher in the control than in the Hwangki with Chungkukjang sample. Color features, such as lightness, redness, and yellowness, all decreased during fermentation, in both control and test. The highest ACE inhibition rates during fermentation at $40^{\circ}C$ were 90.9% in the control (48 hr after fermentation commenced) and 95.3% in Hwangki with Chungkukjang(24 hr). Fibrinolytic activities of Chungkukjang and Hwangki Chungkukjang were 100.7 and 74.4% respectively. The content of 2,6-dimethyl pyrazine in the control was higher than that in Hwangki with Chungkukjang. Sensory evaluationtests showed that the addition of Hwangki significantly improved the overall palatability of Chungkukjang.