• Korean Journal of Food Science and Technology
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• v.50 no.6
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• pp.601-607
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• 2018

We examined the physicochemical characteristics of radish kimchi supplemented with either 10% boneless or boned sliced gizzard shad (BLGS and BGS, respectively) and compared them to those of untreated kimchi during an eight-week fermentation period. BLGS- and BGS-containing kimchi showed higher acidity, amino nitrogen, and Lactobacillus levels than control kimchi. Furthermore, BGS-containing kimchi showed higher acidity, amino nitrogen, and Lactobacillus levels, and lower reducing sugar contents than BLGS at the optimum- and over-ripened stage. Higher amino nitrogen serves as a good medium for microorganism growth, which produce organic acids, consequently decreasing the reducing sugar, pH levels and increasing the acidity. The preference test showed that the control kimchi was the most preferred at the unripened stage, while the BLGS- and BGS-supplemented kimchi samples in the ripened and over-ripened stages showed similar preferences. In conclusion, our results indicate that gizzard shad-supplemented kimchi shows positive health characteristics, such as low salinity, high amino nitrogen and Lactobacillus levels.

• Korean Journal of Medicinal Crop Science
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• v.26 no.6
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• pp.482-489
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• 2018

Background: This study was carried out to determine the physicochemical components of Rehmannia glutinosa (RG) fermented with Rhizopus delemar. Methods and Results: Physicochemical components such as changes in moisture content, pH value, total acidity, amount of reducing sugars as well as quantity of free sugars, free amino acids, and catalpol were investigated. Result showed that, the moisture content ranged from 64.26 to 65.51%. The pH and total acidity of the fermented RG decreased significantly during fermentation. The reducing sugar content ranged from 0.10 to 1.34%. The most abundant main free sugars were identified as raffinose, xylose, glucose, fructose, and sucrose. The sucrose content in 80% ethanol and in water extracts increased during RG fermentation. In total, 26 free amino acids were detected, including seven essential amino acids. In addition, the quantity of free amino acids decreased significantly during fermentation. Finally, the catalpol content of the fermented RG was highest on the $2^{nd}$ day of fermentation at 2,028.67 mg/ 100 g. Conclusions: These results indicated that fermentation of Rhizopus delemar could be used to enhance biological activity, and that fermented RG could be used as a functional material and as an edible resource in food and functional materials industries.

• 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.

• The Korean Journal of Food And Nutrition
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• v.27 no.5
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• pp.971-978
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• 2014

Investigation of the quality characteristics of Takju brewing mashes prepared with several different yeasts was carried out during the 42-day brewing process, including examination of titratable acidity, amino acid content, sugar contents, alcohol contents, pH, reducing sugar, yeast population, lactic acid bacteria, and sensory evaluation. Fermivin yielded the highest titratable acidity, while la parisienne had the lowest. Fermivin also had the highest value of amino acid content (14.33%), while other yeasts shows period tended to increase over exclude Instaferm and Song chun. The amount of sugars in instaferm ($11.33^{\circ}Bx$) and instaferm red ($10.53^{\circ}Bx$) were higher than those in La parisienne red and Song chun ($9.57^{\circ}Bx$). The alcohol contents of instaferm was the highest value (15.20%) while the alchol content of the other yeasts tended to increase the fementation period. Fermivin had the highest pH at $12^{th}$ day among the yeasts(4.02), Instaferm red had the lowest pH among the yeasts (3.87) while safbrew wb-06 had the highest reducing sugar content(117.60 mg/mL). Instaferm obtained the highest preference in the sensory evaluation for all items.

• The Korean Journal of Food And Nutrition
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• v.26 no.3
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• pp.553-564
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• 2013

The core ingredient of traditional Korean style soy sauce is soy bean without any wheat or rice incorporated. National brands as well as regional micro-brewed companies constitute the soy sauce market in Korea. The present study investigated the physico-chemical and sensory properties of soy sauces produced by small-scale or mass-production. Additionally, the key physico-chemical parameters sufficiently representing the critical sensory characteristics have been identified. Ten types of soy sauce brewed by the Korean traditional method were selected for the study. Among these samples, seven types were brewed in small-scales in the Gyeonggi-do region whereas the other 3 types were mass-production products of major national brands. The total solid, reducing sugar, salinity, sugar content, amino nitrogen, CIELAB, acidity, and pH of soy sauce samples were measured for the physico-chemical analysis. A generic descriptive analysis was conducted to analyze the sensory characteristics of the samples using six trained panelists. The descriptive panel developed 21 sensory attributes. The data were statistically analyzed using ANOVA, PCA and PLSR. Overall, the micro-brewed products showed significantly higher value of salinity and acidity but lower content of reducing sugar than the mass-production products. The micro-brewed soy sauces elicited stronger fermented flavor, sourness, and bitterness whereas the national brand products elicited stronger alcoholic odor, sweetness and umami taste. Sugar content, acidity, and amino nitrogen showed strong relationships with fish sauce flavor, umami taste, and rich flavor. Salinity was closely related to the overall flavor intensity.

• Korean journal of food and cookery science
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• v.32 no.6
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• pp.686-695
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• 2016

Purpose: This study aimed to investigate the quality characteristics of traditional and commercial soybean pastes (Doenjang) for development of traditional soybean pastes. Methods: Proximate compositions, amino acid nitrogen contents, pH, acidity, salt contents, chromaticity, viable bacteria and inorganic substance contents of nineteen traditional and three commercial Doenjang were investigated. Results: Analysis of proximate compositions indicated a significant difference between samples. In moisture content, D10 did not meet the standard of food codex. The contents of moisture, fat, protein and ash were slightly higher in traditional than commercial Doenjang. However, the carbohydrate content was 2-fold higher in commercial than traditional, and thus, the calories were also higher. The amino nitrogen content was lower in commercial than traditional Doenjang. pH, acidity and salt contents of Doenjang were pH 4.67-6.15, 1.53-3.29%, and 9.01-18.78%, respectively. pH and acidity showed no significant differences between traditional and commercial Doenjang, however, salt contents were significantly higher in traditional than commercial Doenjang. In case of chromaticity, the averages of L, a, b values were higher in traditional Doenjang. In microbiological analysis, total bacteria counts were higher in traditional than commercial Doenjang. The number of Bacillus cereus in D12 and D19 exceeded the standard of food codex. Staphylococcus aureust was undetected in all samples. The number of fungi varied widely between samples, with no detection in five traditional and all commercial Doenjang. Results of inorganic substance analysis indicated that contents of inorganic substances in Doenjang were in order of Na, K, Mg and Ca. Overall, Na content was higher in traditional Doenjang. Contents of inorganic substances showed wide variations in traditional Doenjang. Conclusion: For the development of traditional Doenjang, quality standardization and ensuring safety are considered necessary.

• Food Science and Preservation
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• v.8 no.4
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• pp.449-455
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• 2001

Changes in pH, titratable acidity, reducing sugar, nitrogen compound and mineral of black bean chungkugjang(BBC)added with kiwi and radish during fermentation were investigated. During fermentation of BBC, pH was increased, while titratable acidity was decreased. The changes in pH and titratable acidity of all chungkugjangs other than BBC were very rapid after 24 hrs of fermentation. Reducing sugar content was highest in BBC and was increased by 24 hrs of fermentation and decreased thereafter. Amino-type nitrogen increased rapidly after 24 hrs of fermentation. The addition of kiwi and radish increased the content of amino-type nitrogen in BBC by enhancing proteolysis of black bean, being as much as in soybean chungkugjang. At 72 hrs of fermentation BBC was found to be lower in ammonia type nitrogen than soybean chungkugjang. Mineral content, in general, was higher in BBC than in soybean chungkugjang, showing highest in potassium followed by phosphorus, magnesium and calcium.

• Korean journal of food and cookery science
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• v.29 no.6
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• pp.671-677
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• 2013

The objective of this study was to examine the levels of free amino acids and identify the correlation between ${\gamma}$-aminobutyric acid (GABA)and L-glutamic acid contents in Kimchi during fermentation. During 2 weeks of fermentation, the acidity of Kinchi increased, i.e., the pH level decreased from 5.24 to 4.40. The content of amino acids determined using HPLC differed significantly (p < 0.05) during 7 weeks of fermentation. Over the 7 weeks of fermentation, the content of most free amino acids increased in the order L-valine > L-glutamic acid > L-glycine, except L-methionine decreased. Initially, the GABA content was found to be $72.43{\mu}M/100g$ fresh weight (fw), and it increased to $229.06{\mu}M/100g$ fw after 7 weeks. This rapid increase in the GABA content in the initial stage is considered to be due to L-glutamic acid. However, during the period of 0~7 weeks, no correlations were found between the L-glutamic acid and GABA contents.

• Culinary science and hospitality research
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• v.18 no.3
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• pp.191-205
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• 2012

Due to a surplus of rice on the market, there has been a growing interest in developing better processed rice products, especially rice liquor or spirits which are popular and have a large market value. In this study, Takju was made with different varieties of rice and rice powder particle sizes, after which a taste survey was performed and measurements were taken on the characteristics of Takju including the temperature of the fermenting material, sugar content, alcohol content, acidity, amino acid types, colors, etc. The varieties of rice used in the study included Chucheong, Hiami and Anda. The temperature of the brew for each kind of Takju reached its highest point 48 hours after preparation. Differences among rice varieties were only apparent in the acidity and taste evaluations. The acidity was found to be highest with Anda, followed by Chuchoeng and Hiami. Chuchoeng had the highest taste evaluation scores. With regards to particle sizes, the alcohol content and acidity were found to be highest with coarse rice powder while ultra fine rice powder showed the highest fermenting temperature, sugar content, acidity, amino acid type, pH level, color and taste scores right after preparation. The results of this study suggest that among the kinds of Takju made from different rice varieties and particle sizes, the one made from Chucheong ultra fine rice powder is the most preferable over other variations.

• 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.