• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.6
• /
• pp.1050-1057
• /
• 1997

Microbial counts, enzyme activities and taste components of traditional kochujangs prepared with the powders from 4 different varieties of red pepper, were investigated during 90 days fermentation for the industrial production of traditional kochujang. The viable cell counts of anaerobic bacteria in kochujangs did not change remarkably during fermentation, however, aerobic bacterial counts showed a rapid increase up to 90 days of aging. The yeasts in all kochujang samples increased until 60 days of aging and than decreased. After 90 days of aging, the count of aerobic bacteria in Kumtop kochujang was higher than those of others. The activities of liquefying amylase decreased during the aging, but those of saccharogenic amylase increased at 60 days of aging. The activities of neutral protease were higher than those of acidic protease, and increased during the middle and last period of aging. The major free sugars of kochujang were maltose and glucose, and their contents were higher in Hongkwang kochujang. The major organic acids of kochujang were succinic, formic and citric acid, followed by lactic acid. Succinic acid content in kochujang decreased during fermentation, whereas formic and citirc acids were increased. The major free amino acids were serine, proline, glutamic acid, aspartic acid and alanine. Kumtop kochujang contained the highest amount of total free amino acids. Among the nucleotides and related components in kochujang, cytidine-5-monophosphate was the most abundant component at the begining of aging period, while hypoxanthine increased remarkably during fermentation. Hanwang kochujang was higher in the content of nucleotides than others. Capsaicin contents of kochujang decreased during aging and those of Jangter kochujang was higher than that of others. Sensory evaluation showed that Jangter kochujang was significantly better than Kumtop kochujang in overall acceptability, but there were no appreciable differences in color and flavor.

• Journal of the East Asian Society of Dietary Life
• /
• v.13 no.4
• /
• pp.305-312
• /
• 2003

The effect of addition of ethanol and/or organic acid on slowing down the fermentation of Mul-kimchi was tested by measuring the changes in pH, acidity and counting the number of microorganisms in kimchi fermentation, and sensory evaluation were carried out. The addition of 0~5％ ethanol to kimchi delayed the decrease of pH and the delaying effect during kimchi fermentation was dependent on the ethanol concentration used. The pH of kimchi without ethanol decreased from 5.7 to 4.13, however, the pH of the kimchi added with 5％ ethanol only from 5.8 to 5.14. The increase of acidity in kimchi with 5％ ethanol was only 0.5~0.6％, while that without ethanol was 0.7~0.8％. Among the organic acids tested, adipic acid was found to be most effective on the prevention of kimchi souring. The Mul-kimchi added 2％ ethanol together with 0.1％ organic acid showed similar effect to that of organic acid alone in the change of pH and acidity. By the sensory evaluation, Mul-kimchi with 0.1％ adipic acid and 2％ ethanol was selected the most desirable one except control without any addition. And the numbers of total microbes, lactic bacteria and yeast count, showed the most effective inhibition in Mul-kimchi with 0.1％ adipic acid and 2％ ethanol.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.34 no.3
• /
• pp.163-168
• /
• 2014

This study was conducted to investigate the effects of bacterial inoculation (Lactobacillus plantarum) and cutting height on the chemical composition, fermentation characteristics and in vitro dry matter digestibility (IVDMD) in whole crop barley silage. Barley forage (Youngyang hybrid) was harvested at about 27% of dry matter (DM) level at two different cutting height (5 vs. 15 cm). And it was chopped to 5 cm length and treated with or without L. plantarum. Four replicates of each treatment were ensiled into 10 L mini silo (3 kg) for 100 days. After 100 days, bacterial inoculation decreased (p=0.001) DM content, while increased cutting height increased (p=0.002) DM in uninoculated silage. Crude protein (CP) concentration was decreased by increasing height in uninoculated silage (8.84 vs. 8.16) but increased in inoculated silage (8.19 vs. 8.99). Both neutral detergent fiber (NDF) (p<0.011) and acid detergent fiber (ADF) (p<0.004) were decreased by increasing cutting height of forage at harvest. The IVDMD and ammonia-N was increased (p=0.001) by increasing cutting height and inoculation, respectively. Lactic acid bacteria (LAB) was increased (p=0.002) in inoculated silage, but yeast count was decreased (p=0.026) in uninoculated silages. It is concluded that increased cutting height of forage at harvest could be useful to make a fibrous portion with increase of dry matter digestibility of silages.

• Journal of the East Asian Society of Dietary Life
• /
• v.14 no.6
• /
• pp.608-617
• /
• 2004

This study is conducted to find out the appropriate preparing method and fermenting condition through analysis of physicochemical, microbiological, sensory evaluation of Myungtae sikhae, Korean fermented fishery food which was prepared in simplified and conventional methods. During the fermentation of sikhae at 4℃, pH was decreased gradually, but acidity was increased and salinity was steady state. In this aspect, no significant difference was revealed between sikhae prepared in simplified and conventional methods. Under fermentation at 20℃ and kept at 4℃, pH was decreased to 4.6～4.9 for 15～20 days fermentation with steady state of salinity. However, acidity was changed in conversely. The content of reducing sugar with rapidly decreasing in the beginning of fermentation was continually decreased. The propagation of microorganism in th sikhae depends on the fermentation temperature rather than the preparing methods. Generally low propagation of microorganism began to increase gradually in the sikhae fermented at 4℃ comparing to that fermented at 20℃. In the sikhae fermented at 20℃ and kept at 4℃, the total count including lactic acid bacteria, was rapidly increased after 5 days' fermentation of sikhae is dominated by Lactobacillus sp. and the unique flavor and organic acid were contributed by this flora with Leuconostoc. sp. By the sensory evaluation, the best flavor was revealed in the sikhae, prepared in simplified method fermented for 30 days at 4℃. Until 20 days, sikhae fermented at 20℃ revealed higher score than fermented at 4℃. General preference for the sikhae fermented at 4℃ for 15 days prepared by simplified method and those fermented at 20℃ for 10 days. The sikhae, fermented at 4℃, showed less difference between preparing methods and preferable acceptability after being 25 days. The best acceptability of sikhae fermented at 20℃ showed after 15～25 days. In the final conclusion, the appropriate preparing method of sikhae is to use frozen Alaska pollack with simplified method and fermented at 20℃ for 5 days and then kept at 4℃.

• Animal Bioscience
• /
• v.36 no.5
• /
• pp.797-809
• /
• 2023

Objective: Many scientists have investigated solutions to reduce microbiological risks in dry-aged meat after the dry-aging technology was revived for high quality and value-added premium meat product in the market. This study aimed to investigate the effect of scoria powder in onggi (Korean earthenware) on the meat quality of pork loins during 21 days of dry aging and to elucidate its mechanism of action. Methods: The pork loins were randomly divided into three groups: aged in vacuum-packaging, onggi containing red clay only (OR), and onggi containing 30% red clay and 70% scoria powder (OS). Microbial analyses (total plate count and Lactobacillus spp.) and physicochemical analyses (pH, shear force, volatile basic nitrogen [VBN], water activity, 2-thiobarbituric acid reactive substances, water content, water holding capacity, cooking loss, and color analysis) of aged meat were conducted. Far-infrared ray emission, quantification of immobilized L. sakei and microstructure of onggi were investigated to understand the mechanism. Results: On day 21, the meat aged in OS exhibited lower pH, shear force, VBN, and water activity than those aged in OR, along with an increase in the number of Lactobacillus spp. OS had a smaller pore diameter than OR, implying lower gas permeability, which could promote the growth of L. sakei. Conclusion: OS improved the microbiological safety and storage stability of pork loin during dry aging by increasing number of Lactobacillus spp. possibly due to low permeability of OS.

• Food Science of Animal Resources
• /
• v.26 no.4
• /
• pp.525-531
• /
• 2006

Effects of Chlorella powder on the growth of lactic acid bacteria, ripening velocity and organoleptic properties in Appenzeller cheese were investigated. Added levels of Chlorella powder were 0, 0.5, 1.0 and 2.0%. The lactic acid bacteria count was higher in cheese added with Chlorella than those in the control cheese. The pH of cheese increased gradually after 3 weeks, reaching pH $5.4{\sim}6.2$ at 15 weeks of maturation, and the pH was slightly lower in Chlorella added cheese than in control cheese. The soluble nitrogen compounds, non casein nitrogen (NCN) and non protein nitrogen (NPN), in Appenzeller cheese increased during 15 weeks of ripening, and they were higher in Chlorella added cheese than in control cheese. Electrophoresis of cheese proteins revealed that caseins were degraded more rapidly in Chlorella cheese as the level of Chlorella increased so that the cheese with 2% Chlorella could have developed a bitter taste and a stench by an excessive degradation of proteins. Sensory scores of the cheese ripened for 15 weeks were diminished as the level of Chlorella increased especially the cheese added with 2% Chlorella obtained significantly lower values of sensory scores than control cheese. Among the Chlorella cheeses, 0.5% Chlorella added cheese showed the highest score in overall sensory preference. From the results, the adequate level of Chlorella powder being added to produce an Appenzeller cheese product with acceptable quality was suggested to be 0.5%.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.39 no.2
• /
• pp.301-307
• /
• 2010

This study evaluates quality of Nuruk, which is a source material of Takju, collected in Daegu and Gyeongbuk and investigates fermentation characteristics of Takju made of it. Totally 7 types of Nuruk were examined and their pH and titratable acidity were 5.4~5.9 and around 0.1%, respectively. Saccharifying activity was high in D, F, G, A and E Nuruk by recording over 300 mg%. Lactic acid bacteria count was the highest in G Nuruk with $3.78\times10^8$ and yeast and total microbe count recorded the highest levels, $3.78\times10^8$ and $3.47\times10^8$, respectively in B Nuruk. When quality characteristics of Takju made of each type of Nuruk were compared, alcohol content was the highest in G Nuruk by recording 19.0% and titratable acidity was 0.44~0.86% in all samples. Hunter's color, brown color and turbidity showed different levels according to types of Nuruk and all lactic acid bacteria, yeast and total microbe counts were the highest in A and E Nuruk. For alcohol components, E and G Nuruk showed high fusel oil content levels and methanol and fusel oil contents of all samples were suitable as standards, respectively. The total organic acid content was the highest in B Nuruk at about 4,000 mg% and it was 2,000 mg% and around 1,000 mg% in A, E, F and G Nuruk and C and D Nuruk, respectively. The content of total free amino acid was the highest in B Nuruk at 3,676 mg% and it was observed to be 1,890, 1,676 and 1,531 mg% in G, E and C Nuruk in that order, respectively. Sensory preference of subjects in their 20s was high overall in G and C Nuruk and that of those in their 40s was high in F and C Nuruk. From all of these results, the types of Nuruk largely affected quality and components of Takju and an appropriate method to consider useful purpose is needed.

• The Korean Journal of Food And Nutrition
• /
• v.26 no.2
• /
• pp.273-279
• /
• 2013

The microorganisms producing high protease activity and acid producing ability were isolated from Chunggukjang and kimchi, which were identified as Bacillus subtilis and Lactobacillus planetarum by morphological, biochemical and nutrient requirement. The attempt was made to produce soybean milk yoghurt by using the isolated microorganisms. The mixed culture of Bacillus subtilis and Lactobacillus plantarum exhibited the lowest pH value of 4.23 and highest titratable acidity of 0.88% compared to those of single cultures at $37^{\circ}C$ for 32 hrs, and their total viable count was $4.09{\times}10^8$ $cfu/m{\ell}$. The ${\alpha}$-amylase activity was the highest in culture of Bacillus subtilis after incubation for 24 hrs, while protease activity was most produced in mixed culture of Bacillus subtilis and Lactobacillus plantarum. The amounts of reducing sugars were steadily decreased as soy milk fermentation progressed.

• Korean Journal of Human Ecology
• /
• v.6 no.2
• /
• pp.57-65
• /
• 2003

To investigate quality characteristics of kimchi prepared for the winter around Chonnam area, home made kimchi samples collected from 22 area, and they were stored at -1${\pm}$1$^{\circ}C$. The results were as follows : The pH and acidity of kimchi samples were 4.75 and 0.84%. respectively. Salt concentration was 3.50% and in Redox potential measurement, Eh value was -134.08mV. Ascorbic acid and reducing sugar contents were 10.l8mg% and 13.25mg%, respectively, In color measurement, L value was 52.29 and a and b values were 19.68 and 27.69, respectively. Total viable count was 5.5${\times}$10$\^$6/ and lactic acid bacteria count and yeast were 4.6${\times}$10$\^$5/ and 8.8${\times}$10$\^$5/. respectively. Properties of hardness of kimchi measured instrumentally was 9.26kgf. Alcohol insoluble solids(AIS) content was 5.53% and hot water soluble pectin(HWSP) content and sodium hexametaphosphate soluble pectin(NaSP) content were 17.35% and 29.65%, respectively, also hydrochloric acid soluble pectin(HClSP) content was 53.0%.

• Food Science of Animal Resources
• /
• v.23 no.3
• /
• pp.262-268
• /
• 2003

Kefir is a traditional fermented milk in Caucasusian area and is made mainly of milk fermented with lactic acid bacteria and yeasts. Six typical kefir grains were selected from ten kefir grains collected from different locals in Korea. Kefir grains were gelatinous in texture and had various shapes of villi, grapes, leaves, hulled millets, and towels. To investigate predominant microflora of kefir grains, SPC, MRS, M17, Rogosa, and APT agar media were used for viable cell count MRS, SPC, and Rogosa media were most acceptable for bacterial cell counts of the selected kefir grains. From one or two of the SPC agar plates which contained around 25∼50 colonies, all grown colonies were isolated and identified. Most predominant bacteria was identified as Lactobacillus fermentum by API 50 CHL kit. The proportions of Lb. fermentum and Lb. brevis among the total identified bacteria were around 41~88% and M4%, respectively. To select the best preservation method for kefir grains, refrigeration, freezing, and freeze drying were compared. Freeze drying was found most suitable for the preservation of kefir grains, based upon their acid-producing activities and production of off-flavors.