• The Korean Journal of Food And Nutrition
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• v.24 no.4
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• pp.761-769
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• 2011

The objective of this study was to investigate the physicochemical properties of Korean traditional soy sauces made with soybeans sown in different producing regions(Hadong, Paju) and in different seeding periods(late-May, mid-June, late-June). The total acidity, salt content, chromaticity, browning, amino nitrogen content and the reducing sugar content of the soy sauce samples were compared. It was found that the total acidity level and the amino nitrogen contents were significantly lower in the soy sauce made with mid-June soybeans, and that these properties increased as the sauce aged. Salt content increased with the aging period regardless of the region of production. The reducing sugar content of Paju soy sauce was the highest in late -June, and for the Hadong region, highest in late-May. The sauce made with Hadong soy beans showed an increase in reducing sugar content positively correlated with the aging period. Reducing sugar content in the samples of Paju soy sauce decreased up to 60 days of aging, but increased after this point. In Paju soy sauce, the brightness(L value) was significantly higher in mid-June, and the Hadong variant it was higher in late -May. The yellowness(b value) at the beginning of the aging process was high in late -June for Hadong soy sauce, but overall it was higher in the mid-June period. The more matured soy sauce samples were darker and showed both higher a and b values. The browning was the lowest in the mid -June regardless of the regions and it increased with the aging period regardless of the production regions. The salt, amino nitrogen contents, browning and yellowness showed significant correlations among the samples. In conclusion, the seeding period of soy beans may affect the characteristics of produced soy sauce alongside the aging conditions.

• Korean Journal of Food Science and Technology
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• v.26 no.1
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• pp.23-25
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• 1994

To evaluate the quality difference between rice starch syrup Kochujang (RSSK) and rice flour Kochujang(RFK), moisture content, pH, titrable acidity, reducing sugar, amino nitrogen and color were measured for 90 days. Moisture content was no great difference between samples and was slowly increased during aging. pH of RSSK was 6.03 and that of RFK was 5.94 after mashing. And it was slowly decreased during aging. Titrable acidity was increased with no great difference between RSSK and RFK. Reducing sugar content of RSSK and RFK was 17.0% and 5.8% after mashing respectively. Reducing sugar content was increased till 40 days, but was decreased thereafter. Amino nitrogen content of RSSK was 123.6 mg% and that of RFK was 93.0 mg% after 20 day aging. Lightness of RSSK was higher than that of RFK, but redness was similar between RSSK and RFK.

• Journal of the Korean Society of Food Science and Nutrition
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• v.16 no.4
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• pp.323-327
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• 1987

The sugar contents of Dolwoe, which were prepared in the laboratory and marketed Korean products of Dolwoe, Japanese product of Dolwoe and Korean-roasted products of Dolwoe were analyzed and compared. The contents of total sugar and reducing sugar of stem in prepared Dolwoe tea were 2 times higher than those of leaf. The sugar content of Korean product was similar to that of Japanese, but the contents of total sugar and reducing sugar in Korean-roasted sample decreased to 17.2% and 40.9%, respectively. It was confirmed that free sugar in Dolwoe tea was composed of rhamnose, fructose, glucose and sucrose. The ratio of free sugar content was quite different between Dolwoe-leaf tea and Dolwoe-stem tea. Comparing the free sugar content in prepared Dolwoe tea, glucose was the highest followed by fructose, sucrose and rhamnose. On the other hand, in marketed Dolwoe tea, glucose was the highest substance and followed by fructose, rhamnose and sucrose. It was found that rhamnose content in Japanese product was approximately 6 times more than that of Korean.

• Korean journal of food and cookery science
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• v.14 no.2
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• pp.182-187
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• 1998

The changes in weight, reducing sugar content, sugar composition and enzyme activities (${\beta}$-amylase and invertase) of sweet potato were studied with three kinds of cooking methods, microwave oven, gas oven, and steaming. The weights of sweet potato cooked by microwave oven and gas oven were decreased with increasing cooking time, whereas that of steaming was increased with cooking time. Reducing sugar content of sweet potato cooked by microwave oven was increased till 40 seconds, but decreased thereafter. In the cooking methods using gas oven and steaming, reducing sugar content were increased with cooking time. And reducing sugar content were 334.60 mg/g and 381.29 mg/g, respectively at 100$^{\circ}C$ of cold point in sweet potato cooked by gas oven and steaming. Raw sweet potato consisted of fructose (1.56 mg/g), glucose (1.79 mg/g), sucrose (5.58 mg/g), and maltose (2.22 mg/g). The contents of fructose, glucose, and sucrose were decreased during cooking process. But maltose content was increased with cooking time. Especially, maltose contents were 24.81 mg/g and 28.10 mg/g at 100$^{\circ}C$ of cold point in sweet potato cooked by gas oven and steaming. The activities of ${\beta}$-amylase and invertase were decreased with cooking time. Microwave oven-cooked sweet potato did not show on invertase activity.

• Journal of Ginseng Research
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• v.5 no.2
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• pp.99-107
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• 1981

Physical, chemical and microbiological changes were periodically studied during six-month storage of fresh ginseng under N2, CO2 gas or subatmospheric pressure condition. The results were summarized as follows. 1. The moisture contents of fresh ginseng gradually decreased during the first 2-month storage and thereafter generally reached at equillibrium. 2. There was no significant change in the reducing sugar content in 1-month storage, followed by$.$a decrease in between 2-and 3-month storage. Thereafter, the reducing sugar content increased at the end of 4-month storage. 3. The total sugar content increased significantly during the first 3-month storage. Under CO2 and Nr gas storage, the total sugar content gradually decreased after 3-month storage, while no significant change was observed in the samples stored under subatmospheric Pressure. Amylase activity gradually decreased as storage period increased 4. The content of saponin decreased as storage period increased, but ginsengoide Rf, Rd, Rc and Rb2 increased significantly in 1-month storage. 5. Regardless of storage methods, sprouting of ginseng and growth of microorganisms were inhibited in all samples during the first 4-month storage. However, growth of microorganisms was observed in the rhizome and injured areas of ginseng after 5-month storage in the N2 and CO2 gas atmosphere.

• Preventive Nutrition and Food Science
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• v.13 no.4
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• pp.321-326
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• 2008

In order to improve the market competitiveness of the processed products of Undaria pinnatifida, various extraction conditions of Undaria pinnatifida were examined to determine the optimal conditions for the extraction of its valuable components. The highest level of alginic acid content was detected after 90 min of typical extraction or after 20 min of pressure extraction, after which the levels decreased slightly. The concentrations of reducing sugar and crude protein were also high after 90 min of typical extraction. Both alginic acid and reducing sugar were extracted in greater amounts using pressure extraction. The reducing sugar content was $2.8{\sim}3.2$ times higher using pressure extraction rather than typical extraction. Furthermore, the extraction results were superior with the, pressure extraction method. The appropriate temperature and duration of extraction were found to be $120^{\circ}C$ for 20 min. The use of a single enzyme yielded better results during extraction compared to the use of a mixture of enzymes. 20 min of pressure extraction followed by the addition of 0.1% pectinase and 2 hr of further extraction at $50^{\circ}C$ yielded high contents of alginic acid and reducing sugar from Undaria pinnatifida.

• Korean journal of food and cookery science
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• v.7 no.1
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• pp.27-34
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• 1991

This study attempted to set up reasonable extraction time of Omija that was put in water for the various components to soak out. Changes of free sugars, organic acids, reducing sugar, total acid and tannin in Omija with various extraction times were investigated (together with the analysis of each components in Omija fruit). 1. High Performance Liquid Chromatography showed fructose, glucose, and sucrose to be the major free sugars of the Omija fruit. Free sugars and reducing sugar value in Omija beverage increased gradually in according with the extraction time, and marked 75.6% per total free sugars and 82.1% per total reducing sugar at 12 hours. 2. Gas Chromatography showed lactic acid, oxalic acid, fumaric acid, levulinic acid, succinic acid, malic acid, citric acid and pyroglutamic acid to be the major organic acids of the Omija fruit. Organic acids and total acids value in Omija beverage increased gradually on proportion to extraction time, and marked 97.0% per total organic acids at 9 hours and 79.0% per total acids at 12 hours. 3. Tannin content in Omija beverage was increased when extraction time was longer but it showed a low percentage as compared with the reducing sugar and total acid. Tannin content marked 48.8% per total tannin at 12 hours. 4. Sensory evaluation revealed that !1 hours of extraction produced the best quality products based in taste, flavor, color and over-all acceptability, considering the data, it seems possible to conclude that the optimum of time for extraction of Omija to water is 9 hours.

• Korean journal of food and cookery science
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• v.12 no.3
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• pp.300-304
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• 1996

Jeungpyun Products prepared with different fermentation time (0-10 hours) were analyzed to study phenomena occurred during steaming of Jeungpyun dough. The tendencies of changes in chemical Properties of Jeungpyun Products according to the fermentation time were similar to those of Jeungpyun dough. Titratable acidity, lactic acid, total sugar content, reducing sugar content, soluble protein and total content of free amino acid of Jeungpyun product decreased while its pH increased somewhat, during steaming compared with those of Jeungpyun dough. Especially reducing sugar decreased greatly.

• Applied Biological Chemistry
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• v.35 no.6
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• pp.437-442
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• 1992

In order to develop color of potato chip made from Superior variety and Irish Cobbler variety, various conditions on NaCl and $CaCl_2$ contents, heat treatment and soaking time were applied. The content of reducing sugar decreased by $30{\sim}40%$ in blanching without NaCl and $CaCl_2$. In NaCl soaking case, reducing sugar content decreased by $15{\sim}30%$, however, partial colorization was appeared that the sample turned to brown. In the sample that were soaking in NaCl solution and heat treated, reduction of reducing sugar was 40% and desirable time for heat treatment was 5 min and 7 min. In the sample treated $CaCl_2$ solution, reduction of reducing sugar was $25{\sim}30%$ and then color was not acceptable. In the sample soaking $CaCl_2$ solution and heat treated, reducing sugar content rapidly by 50% and the color development was the most ideal.

• The Korean Journal of Food And Nutrition
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• v.26 no.1
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• pp.101-108
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• 2013

This study investigated the functional nutrition of red yeast rice to added beurre mani$\acute{e}$ in the production of brown sauce. We added X to Y at levels of 0%, 5%, 10%, 15% and 20% and investigated the effects on the viscosity, water content, turbidity, pH, sugar level, reducing sugar, color, and sensory quality characteristics of the resultant brown sauce. The viscosity of Brown sauce was increased with increasing red yeast rice beurre mani$\acute{e}$ while water content and turbidity were decreased. pH was between 4.57~4.91. Sugar level and reducing sugar were increased with increasing red yeast rice powder content. L and a were increased with increasing red yeast rice powder content, and b was decreased. In sensory testing, visual appearance and flavor were highest for brown sauce preparations containing 15% and 20% X. Aftertaste and taste scored the highest for additions of 10% and 15%. For general preference, a 15% addition of X resulted in the highest score. Based on the results, it seems that red yeast rice powder, 15% red yeast rice powder added brown sauce has the highest the general preference.