• Journal of Dairy Science and Biotechnology
• /
• v.33 no.1
• /
• pp.17-25
• /
• 2015

The present study was carried out to evaluate the preparation of the fermented milks with rice bran and to prove that the bacteria used are necessary for providing amino acids in this process. The rice bran on fermented milk with Streptococcus thermophilus (ST-body1) and Lactobacillus casei (LC-10). The fermentation limit was set until acidimetry score reaches 1. There are reports of titratable acidity, pH, viable cell count and amounts of organic acids affecting amino acid production about physical and chemical analysis measured using HPLC. Finally, sensory test was surveyed. In this study, the rate of acidification was higher in the fermented milk with rice bran than in the common fermented milk. In case of the number of cells was $1.0{\times}10^8CFU/mL$ in group. The lactic acid and citric acid content in yogurts prepared with rice bran using Streptococcus thermophilus (ST-body1) and Lactobacillus casei (LC-10) was higher than that in the control yogurt. Amino acids derived by rice bran were effected in fermentation for each bacteria's necessary amino acid production, and it made bacteria growth larger. From the physical test of the fermented milk with rice bran, flavor, texture, sweetness, overall taste of the fermented milk of Streptococcus thermophilus (ST-body1) were found to be much better than those of the other groups. The results obtained for the fermented milk prepared with rice bran using Streptococcus thermophilus (ST-body1) are significant.

• Korean Journal of Food Science and Technology
• /
• v.26 no.3
• /
• pp.300-304
• /
• 1994

To predict quality change of Kochujang distributed in the market, physicochemical properties were observed during storage at $13^{\circ}C$, $27^{\circ}C$ and $37^{\circ}C$ for 240 days. Moisture, crude protein and capsaicin contents were nearly constant for storage at the selected temperatures. Amino nitrogen, value of surface color and pH were decreased during storage while ammonia nitrogen and titratable acidity were increased. Storage temperature affected quality change significantly as higher temperature showed clear increase or decrease phenomena of above factors. Number of total cell count was not changed significantly, and fungi was not detected. From the correlation coefficient among physicochemical properties and sensory evaluation scores, the highest correlation was obtained in amino nitrogen content and sensory score. Degradation of amino nitrogen was a first order reaction, and the $Q_{10}$ value calculated from reaction constant was 2.98. Also, activation energy for the destruction of amino nitrogen calculated from Arrhenius equation was 15.34 Kcal/mole.

• Korean Journal of Food Science and Technology
• /
• v.33 no.2
• /
• pp.256-263
• /
• 2001

Physicochemical characteristics of kochujang prepared with meju, koji and mixture of meju and koji were analyzed during fermentation in order to improve quality of traditional sikhe kochujang. Amino nitrogen content, an index of kochujang quality, was remarkably higher in kochujang prepared with p-2 koji, p-1 koji, mixture of p-2 koji and meju. Titratible acidity of kochujang slightly increased and pH of kochujang increased until 40 days of fermentation and then decreased there after. Citric acid was found as a major organic acid followed in decreasing order by malic, oxalic, succinic, acetic and lactic acids. As a free sugar, maltose, glucose and fructose were detected. Free sugar content was higher in kochujang prepared with p-1 koji than the others. The major free amino acids were aspartic acid, glutamic acid, alanine, phenylalanine and arginine, and total free amino acid content was higher in kochujang prepared with koji, and mixture of meju and koji than the one with traditional meju only. In sensory evaluation, all tested groups did not show a significant difference. This result indicates that addition of koji to sikhe kochujang influences on taste components like free sugars and free amino acids, but decisively not on the sensory properties.

• Applied Biological Chemistry
• /
• v.31 no.2
• /
• pp.154-161
• /
• 1988

In order to improve the quality of amino acid soysauce, this experiment was carried out as follows; koji added amino acid soysauce(KAAS) was prepared by addition of defatted soybean and meal koji into amino acid soysauce containing $0.5%{\sim}1.5%$ of total nitrogen. Various physicochemical characteristics of KAAS during aging were determined. Total nitrogen, amino-nitrogen, specific gravity, pure extract, total acidity and color were high in KAAS at high total nitrogen. After one month aging, reducing sugar was high in KAAS at high total nitrogen, but pH was high in KAAS at low total nitrogen. Ethyl alcohol was 2.07% in KAAS at 0.5% of total nitrogen after five months aging and 1.4% in KAAS at 1.5% of total nitrogen. Levulinic acid and lactic acid were high in KAAS at low total nitrogen. The results obtained above summarized as the quality of KAAS were highly good at $0.5{\sim}0.7%$ of total nitrogen after two or three months aging.

• Journal of Sericultural and Entomological Science
• /
• v.16 no.2
• /
• pp.77-98
• /
• 1974

This study was carried out ill an attempt to investigate the properties and activities of sericin obtained from silk cocoon shells in silk reeling water through various instrumental analyses. In addition, the effects of the characteristics in sericin solubility on the reeling process and silk qualities were also studied on the basis of tile above conditions. The results obtained are as follows： I. The sericin properties and activities through various analytical instruments. 1. The water solubility of each amino acid such as serine, glycine. glutamic and aspartic acids against the pH modified water by using automatic amino acid analyzer, showed the lowest solubility at PH 5, but it increased according to drifting toward the alkalinity. 2. When the obtained sericin particles by water pH variation were observed with the electronic microscope, it was found for the sericin Particles to expand in the alkaline regions. 3. The IR spectrum results showed the differences among the pH modified sericin solutions at the range of 2,100cm-1 and 1.890cm-1 of wave number. 4. The existence of sericin with in silk fabrics made differences in the X-ray interference intencity, that is, the non-degummed fabrics had the interference peak at 2$\theta$=14$^{\circ}$, 17$^{\circ}$, 24$^{\circ}$, and the degummed ones had it at 2$\theta$=17$^{\circ}$, 18$^{\circ}$, 20$^{\circ}$, 23$^{\circ}$, 26$^{\circ}$. II. The results of sericin solubility for silk reeling process. 1. The sericin solubility and swelling had a tendency to increase up with high M-alkalinity and pH value of water. But in case of acidity. water hardness and concentration of ethylene glycol were high, the sericin solubility and swelling were decreased. 2. With the filature experiments, the best conditions of filature orator are summarized as fellows ; a. pH; 6.9${\pm}$0.2 d. acidity; below10ppm b. total hardness; 55：5ppm e. Fe ion; none c. M-alkalinity; 40${\pm}$10ppm

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.7
• /
• pp.1088-1094
• /
• 2014

This study investigated the quality properties of glutinous rice Gochujang produced by regional rural families in order to determine the present state of quality of traditional Gochujang. A total of 80 Gochujang samples were collected from nationwide rural families and their physicochemical characteristics were analyzed. Based on regional mean, ranges of moisture contents, pH, acidity, crude protein contents, and salinity of Gochujang were $44.31{\pm}5.73%{\sim}50.50{\pm}5.65%$, $4.59{\pm}0.36{\sim}4.79{\pm}0.15$, $1.18{\pm}0.22%{\sim}1.54{\pm}0.36%$, $5.28{\pm}0.90%{\sim}6.93{\pm}.09%$, and $5.55{\pm}0.85%{\sim}8.29{\pm}1.19%$, respectively. The mean contents of amino type N, reducing sugars, and capsaicinoids were $488.81{\pm}79.74mg%{\sim}715.16{\pm}78.09mg%$, $22.32{\pm}9.43%{\sim}28.61{\pm}8.80%$, and $44.31{\pm}18.71mg/kg{\sim}65.15{\pm}47.98mg/kg$, respectively, and differences were significant among the Gochujang samples. Hunter color values (L, a, and b) of Gochujang were $4.84{\pm}3.08$, $21.26{\pm}10.53$, and $8.20{\pm}5.91$, respectively, and the range of viscosity was $31,511{\pm}11,764{\sim}72,923{\pm}32,555$ cP. The acidity, salinity, moisture, crude protein, and amino type N contents of Gochujang produced from the Gangwon-do and Gyeonggi-do areas were significantly higher than those of other regions. According to principal component analysis of the physicochemical characteristics of Gochujang produced by rural families, the salinity, acidity, moisture, crude protein, and amino type N contents were strong characteristics of Gochujang produced by Gangwon-do and Gyeonggi-do. These results indicate that traditional Gochujang produced by rural families shows various quality properties and regional differences in physicochemical characteristics.

• Journal of the East Asian Society of Dietary Life
• /
• v.23 no.1
• /
• pp.69-77
• /
• 2013

Jujube is a functional food, containing medicinal ingredients without side effects. Jujube can relieve digestive upset, inhibit tumor growth and protect the liver. It includes sterols, alkaloids, saponins, vitamins, organic acids, and amino acids. Jujube has also received attention as an anticancer agent and as a diet food. However, it is rare to find yogurt made with jujube, so we considered adding jujube powder to yogurt to popularize it as a new health food. We made yogurt with jujube powder at 0, 1, 2, 3, and 4%. We measured pH, acidity, color properties (brightness, redness, yellowness), viscosity, sensory qualities (color, flavor, taste, overall quality). We also experimented with storage stability at intervals of 1, 5, 10, 15, and 20 days. The results showed that pH increased significantly (p<0.001) with increasing amounts of added jujube powder. The pH also rose significantly with longer storage, but tended to decrease after 20 days. Acidity was reduced during the storage period. Viscosity was highest with 1% added jujube powder (p<0.001) on day 5 of storage (p<0.001). The L color value decreased as the amount of added jujube powder increased, whereas the a-value (redness) and b-value (yellowness) increased (p<0.001). In an sensory test, color in samples with 0, 1, and 2% jujube powder exhibited the highest values (p<0.01), but no significant differences in flavor or texture were observed. Sweetness and sourness were highest in the yogurt with 3% jujube powder (p<0.05). Overall quality tended to be higher for yogurt with 3% jujube powder, but the difference was in significant. Taken together, our results indicate that yogurt with 3% jujube powder may the most suitable for manufacturing purposes.

• Journal of Life Science
• /
• v.18 no.10
• /
• pp.1410-1414
• /
• 2008

This study was carried out to develop a vinegar by an onion juice. Onions are considered to be a promising source of the vinegar because these are rich in sugars, amino acids and various nutrients. An Acetobacter for an acetic acid fermentation was isolated and used from vinegars produced by industrial goods or from matured Kimchi. When supplemented with 2-8% ethanol into an onionic juice medium, the highest production of the acetic acid was observed at 9 days by addition of 4% ethanol. Optimum temperature and aeration for acetic acid production were exhibited at $30^{\circ}C$ and 200 rpm, respectively. A flask containing larger air-contact surface region for fermentation was produced the more acetic acid than that of a test tube. Taken all these together, an optimum condition for the acetic acid fermentation was over 9 days at $30^{\circ}C$, 200 rpm with 5% alcohol and 2% initial acidity. When fermented by the upper condition, the final product contains 5.2% total acidity and less than 1% ethanol. These are suitable for conditions of fruit vinegar notified by the Ministry of Commerce, Industry and Energy.

• Korean Journal of Food Science and Technology
• /
• v.43 no.5
• /
• pp.603-610
• /
• 2011

This study was performed to examine the physicochemical characteristics and sensory properties of makgeolli with dried citron peel and levels (3, 6, and 9%) of citron (Citrus junos) in makgeolli during fermentation with two-step-brewing. The pH of makgeolli with citron dried peel increased within 5 days of fermentation, and decreased until 11 days of fermentation. Total acidity increased after 3 days of fermentation then decreased after 5 days of fermentation, but continued to increase slightly up to 12 days. Changes in alcohol content and amino acidity increased during fermentation. A sensoryevaluation of appearance, flavor, sourness, sweetness, bitterness, and overall acceptance of makgeolli with citron dried peel showed lower values than those of the control.

• Korean Journal of Food Science and Technology
• /
• v.49 no.1
• /
• pp.35-43
• /
• 2017

The sensory characteristics of 12 commercial top-fermented beers were determined by sensory descriptive analysis. Beer samples were also analyzed for soluble solids, titratable acidity, pH, reducing sugar content, bitterness unit (BU), turbidity, hunter color values, amino acid content, total phenolic content, and DPPH radical scavenging activity. Five appearance, nine aroma, six flavor/taste, and four mouth-feel related sensory attributes were evaluated by a panel of nine judges. As the result of three way analysis of variance of descriptive data, all sensory attributes except "cereal" aroma and "salty" taste showed significant differences among the beers (p<0.05). Based on the principal component analysis of the descriptive data, samples were primarily separated by first and second principal components, which accounted for 78% of the total variance between the beers with high intensities of "yellow color", "caramel aroma", and "barley taste" versus "hop aroma", "sour", and "citrus aroma". In the correlation analysis between the sensory terms and physicochemical parameters, BU, total phenolic content, titratable acidity, soluble solids, and yellowness ($b^*$) showed significant positive correlations with citrus aroma, pineapple aroma, and fresh aroma characteristics.