• Journal of the Korean Society of Food Science and Nutrition
• /
• v.41 no.12
• /
• pp.1805-1812
• /
• 2012

The effects of red-potato on the physicochemical properties of kochujang were investigated during fermentation. The number of yeast and aerobic bacteria in kochujang increased up to 4 weeks of fermentation, then the yeast number slowly decreased. Amylase activities also increased after 2~4 weeks of fermentation with the addition of red-potato. The Hunter L-value of kochujang decreased sharply and the a-value increased through the addition of starch syrup, causing major changes in total color difference as the ratio of red-potato increased. There was a direct correlation between the amount of red-potato with water activity and titratable acidity. The oxidation-reduction potential of kochujang decreased sharply after 12 weeks of fermentation, and was lowered with the addition of red-potato. As the ratio of red-potato increased, reducing sugars and ethanol contents of kochujang increased in the later stage of fermentation, while the amino-type nitrogen content was lower. Sensory results showed that a final percentage of 2% red-potato in kochujang was optimal for taste and overall acceptability.

• The Korean Journal of Food And Nutrition
• /
• v.10 no.3
• /
• pp.365-369
• /
• 1997

Glutinous rice Sikhye was fermented by Saccharomyces cerevisiae for 10 day at 29$^{\circ}C$. Fermentable sugars such as maltose and maltotriose in glutinous rice Sikhye were converted into ethanol by the yeast, but limit dextrin was remained after the fermentation. fermentation rate of sugars in glutinous rice Sikhye was lower than that in rice Sikhye. Glutinous rice Sikhye wine was found to contain 7.3% of limit dextrin, 3.6% of ethanol, 0.35$\mu$mol/ml of amino acid, 100$\mu\textrm{g}$/ml of protein, and the acidity of the Sikhye showed 3.2, respectively, and its pH was 3.23. Limit dextrin in glutinous rice Sikhye wine showed both signal of $\alpha$-1, 4- and $\alpha$-1,6- glucisidic linkage with its estimation ratio of 5.6:1 by 1H-NMR analysis. The taste of rice Sikhye wine was similar that of wine.

• The Korean Journal of Food And Nutrition
• /
• v.31 no.5
• /
• pp.712-719
• /
• 2018

This study was carried out to obtain basic data on Korean traditional Meju collected from 18 regions (TM1~TM18) in Korea and to define and control quality. The shape of Meju was mostly rectangular and the weight was 0.84~2.04 kg. The physicochemical analysis showed: pH, 5.31~8.21; total acidity, 0.91~2.74%; moisture content, 4.79~42.16%; and soluble protein content, 41.37~23.48%. Hunter color values for L (lightness), a (redness), and b (yellowness) ranged from 39.07~67.92, 3.57~8.87, and 7.48~20.67, respectively. The amino nitrogen contents of all samples were in the range of 257.29 to 839.58 mg% and TM13 showed the highest content (839.58 mg%). Total viable cells, yeast and mold counts of Meju were 8.43~5.91 log CFU/g, 2.48~5.19 log CFU/g, and 3.42~7.48 log CFU/g, respectively. Based on the results, it is proposed that quality standards and management of Meju fermentation conditions and information about different varieties of soybeans used should be made available.

• The Korean Journal of Food And Nutrition
• /
• v.32 no.6
• /
• pp.687-695
• /
• 2019

The purpose of this study was to investigate the quality characteristics of Doenjang made by seven different traditional soybean paste manufacturers, in Chungbuk province during fermentation. The moisture content of Doenjang declined in the process of fermentation, from 58.07~68.86% to 52.32~63.79%. The salinity increased from 7.47~14.38% to 10.42~17.73%. Sample B was the lowest, and G was the highest. The pH showed a tendency to decline from 5.36~6.22 to 4.30~5.66 except for sample F, which increased 6.33~7.10. In contrast, the total acidity showed a tendency to increase from 0.56~1.77% to 1.11-1.83% except for sample F, which declined 0.71%~0.54%. The lightness declined from 44.33~55.90 to 26.68~49.66. However, the redness and the yellowness generally increased. The content of amino type nitrogen generally increased with the progress of fermentation from 93.33~408.80 mg/kg to 314.07~1,258.13 mg/kg and sample D, with Aspergillus oryzae added, was the highest. The volatile flavor compounds of Doenjang had 10~20 types. Sample D had the fewest number of volatile flavor compounds (10 types of compounds), and sample C had the largest number of it (20 types of compounds). Four types of compounds, ethanol, 3-methyl butanal, ethyl acetate, and 3-methyl butanoic acid, were detected from all samples.

• Korean Journal of Food Science and Technology
• /
• v.24 no.1
• /
• pp.92-96
• /
• 1992

Several coagulants was investigated for their effects on shelf-life of packed Tofu. The titratable acidity, amino nitrogen content in Tofu and the optical density of Tofu suspension were increased as the spoilage developed during storage. The number of microorganisms was increased to 13 million cells per gram after 1 day of storage at $30^{\circ}C$ in the Tofu prepared with $MgSO_{4}\;and\;CaCl_{2}$. But, the Tofu prepared from acetic acid was found to be more stable for storage. The quality of Tofu was maintained up to 12 days or 18 days at $30^{\circ}C\;or\;15^{\circ}C$, respectively. These results suggested that acetic acid was desirable as a coagulant of packed Tofu to extend its shelf life.

• Korean Journal of Food Science and Technology
• /
• v.49 no.3
• /
• pp.265-273
• /
• 2017

In this study, the effect of nuruk prepared from rice with different degrees of milling on the physicochemical and sensory qualities of yakju after accelerated aging was investigated. The results indicated significant differences, except for Fe and Mn contents, in the qualities of aged yakju prepared using nuruk from rice with different degrees of milling. However, the degree of milling of rice did not influence the quality of yakju, except for amino acidity and pH, which significantly decreased as the degrees of milling increased. In addition, as compared to before aging, brownness ($A_{430}$) and color difference significantly increased after aging in all the treatments. The intensity of off flavor in yakju after aging made from 0% milled rice nuruk was the lowest.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.6
• /
• pp.870-875
• /
• 2003

Physicochemical characteristics of Kochujang based on hot-air dried the red pepper powders with different treatments, were investigated during 90 days fermentation to obtain information for the industrial production of Kochujang. The pH was decreased gradually during fermentation, and pH of the control Kochujang was consistently higher than those of others. The total acidity was increased linearly during fermentation, and Kochujang with 0.1% vitamin C was consistently higher than others. Reducing sugar contents of Kochujang was increased until 75 days but was decreased slightly thereafter, showing highest value for the control sample. Amino nitrogen contents was increased gradually until 75 days, showing highest value for Kochujang with mash-dried red pepper powder, but it was decreased remarkably thereafter The L and a values of Kochujang were increased, whereas b value was decreased during fermentation. L, and b values of Kochujang with mash-dried red pepper powder were higher than those of others, showing the more light and deep color than others. Appearance, taste and overall acceptability of Kochujang based on mash-dried red pepper powder were higher than others.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.5
• /
• pp.775-783
• /
• 1997

Morphologically different 18 strains were isolated and examined for their abilities to inhibit ACE. Those strains were cultured in the medium containing 10% of soybean extract at 37$^{\circ}C$ for 48hr or fermented with boiled soybean at 3$0^{\circ}C$ for 60 days. The concentration of inhibitors to inhibit 50% of ACE activity, $IC_{50}$ was measured on the culture broth of each strain and also on the hot-water extract from 20, 40 and 60 day fermented Doenjang by each strain. As a result, SCB-3 which is isolated from Meju showed the highest ACE inhibitoryactivity on the cultured broth and 40 day matured Doenjang. Then, $IC_{50}$ of SCB-3 was 0.02 mg/ml and 0.26mg/ml respectively. SCB-3 was identified as a Bacillus subtilis based upon its morphological, biochemical and physiological properties. Changes in general components and ACE inhibitory activity of Doenjang fermented by SCB-3 were examined during 90 days. Total acidity of Doenjang was increased from 1.39% to 1.66% and pH was decreased from 6.02 to 5.79 after 90 days fermentation. Total sugar contents were decreased from 16.4% to 15.1% and reducing sugar contents was also decreased from 2.45% to 1.62%. Total nitrogen contents were nearly not changed, but amino nitrogen contents were drastically increased from 196mg% to 541mg%. The numbers of total microorganism were increased to 1.1$\times$$10^{8}$ cells/g after 45 days. Protease activity was increased to 622.1U/g after 75 days. The highest ACE inhibitory activity was shown in 60 day fermented Doenjang and $IC_{50}$ of the hot-water extract was 0.31mg/ml.

• Fisheries and Aquatic Sciences
• /
• v.20 no.7
• /
• pp.13.1-13.7
• /
• 2017

In order to evaluate the maximal storable period of the raw crab for a non-thermal muscle separation, the quality changes of the leg meat of red snow crab (Chionoecetes japonicus) during freeze storage were investigated. Fresh red snow crabs were stored at $-20^{\circ}C$ for 7 weeks, and the leg muscle was separated by a no heating separation (NHS) method every week. During the storage, considerable loss of the leg muscle did not occur and microbiological risk was very low. In contrast, discoloration appeared at 2-week storage on around carapace and the leg muscle turned yellow at storage 3-week. In physiochemical parameters, protein and free amino acids gradually decreased with storage time, expected that proteolytic enzymes still activated at $-20^{\circ}C$. At 4-week storage, the sensory acceptance dropped down below point 4 as low as inedible and notable inflection points in pH and acidity were observed. The volatile base nitrogen was low, though a little increase was recorded. These results suggested that the maximal storable period at $-20^{\circ}C$ of the raw material was within 2 weeks and it was depended on external factor such as the discoloration. The present study might be referred as basic data for approaches to solve quality loss occurred in non-thermal muscle separation.

• The Korean Journal of Food And Nutrition
• /
• v.33 no.5
• /
• pp.524-531
• /
• 2020

The purpose of this study was to evaluate the quality properties of Meju prepared by inoculating two strains of Bacillus amyloliquefaciens HJ5-2, and Aspergillus oryzae PS03. The three soybean varieties that include Daewonkong, Daechan, and Saedanbaek were used in this experiment. The fermentation temperature during the Meju aging varied at 20℃, 30℃, and 40℃, respectively. The physicochemical analysis of the soybeans, showed that the cured protein and fat contents were 34.83~43.49% and 12.91~18.90%, respectively. The pH and total acidity were 6.47~6.93 and 0.11~1.22%, respectively. The change in appearance of the Meju was that the yellow-green mold was well formed on seven days at fermentation temperature of 20℃ and 30℃, but at 40℃, there was minimal mold formation and cracking of the surface. The amino nitrogen content was highest on the Daechan Meju at 621.83 mg% for seven days. The amylase increased as the fermentation period increased in all samples, and the protease increased rapidly until the first day of the fermentation, and then gradually increased thereafter. The total number of bacteria increased or decreased as the fermentation proceeded to 6.66~10.07 log CFU/g. The mold counts increased with increasing fermentation period in the range of 6.38~8.79 log CFU/g.