• Fisheries and Aquatic Sciences
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• v.4 no.3
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• pp.144-149
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• 2001

In other to establish the exact determination method of amino nitrogen (AN) in salt-fermented fish sauces, we determined the AN in fish sauces according to the measuring methods and also investigated the main factors influencing on determination method of AN. AN in salt-fermented anchovy sauce increased linearly as fermentation progressed, and was shown the highest amount measuring by the Formol method, followed by the trinitrobenzene sulfonic acid (TNBS) method and the Copper-salt method. AN concentration in anchovy sauces fermented for 12 months was $88.2\%$ and $77.6\%$ for the TNBS method and the Copper-salt method, respectively, on the basis of Formol method. The ratio of AN/total nitrogen (TN) in anchovy sauce fermented for 12 months was higher than that in commercial anchovy sauces. The determination of AN in anchovy sauce by the TNBS method was not affected by salt concentration, and slightly affected by heating. The effect of MSG on AN contents by Copper-salt method was shown higher than those by the Formol method and the TNBS method. The TNBS method was adaptable to measure the content of AN in fish sauce by this study.

• Korean journal of food and cookery science
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• v.11 no.3
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• pp.244-248
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• 1995

This study was carried out to investigate the free amino acid content, the free amino-nitrogen content and minerals such as Ca, P and Fe of chicken bone stock. The results were as follows. 1. In chicken bone stock, glutamic acid was the most abundant amino acid, Iysine, alanine, cysteine and glycine were followed oderly and these free amino acids seemed to be the most intensive flavor compounds. 2. The free amino acid-nitrogen content of chicken bone stock was increased after 3 hours boiling and began to decrease after 4 hours boiling. 3. After 3 hours boiling, Ca, P were 5.0 mg/100 g chicken bone and 42.5 mg/100 g chicken bone, respectively and began to decrease after 4 hours boiling. The ratio of Ca:P was about 7.8. Fe was increased after 4 hours boiling and began to decrease after 5 hours boiling. These results revealed the low effectiveness of Ca, P and Fe utilization of chicken bone stock, because of the very low extraction of minerals. But these results revealed the significant correlation of free amino acid, free amino-nitrogen contents and brothy flavor. So chicken bone stock on heating at 90-95$^{\circ}C$ for 3∼4 hours seemed to be the most intensive brothy flavor.

• The Korean Journal of Ecology
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• v.22 no.3
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• pp.109-117
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• 1999

Thirty two species of coastal plants (mainly halophytes) were investigated for their free amino acids and the total and water-soluble nitrogen contents in leaves. All plants except some species (e.g. Scutellaria and Linaria) contained proline, but only Ageratum. Tetragonia and Raphanus in rather high amounts, that it can be thought to serve as a cytoplasmic osmolyte. In some plant species (Euphorbia. Glehnia. Peucedanum. Raphanus and monocotyledonous Carex and Zoysia), however, hydroxyproline. (OH-Pro) rather than proline were accumulated to a considerable extent. The concentrations of total free amino acids were low in Aster tripolium, Linaria. Lysimachia. Plantago. Rumex, Vitex and especially in the members of the Chenopodiaceae and Crassulaceae. Marked differences also occurred in the nitrogen levels. Aizoaceae, Chenopodiaceae, Convolvulaceae, Cruciferae, Euphorbiaceae and Leguminosae usually showed high values of total and soluble amino nitrogen, while the opposite was true for most of the Cyperaceae, Gramineae, Lamiaceae, Plantaginaceae, Scophuriaceae, and Verbenaceae. The free amino acids in the investigated plant species contributed very little to the nitrogen content, but in plants of Euphorbia, Messerschmidia and Orostachys. their amino acid-N made up for 25∼30% of the total nitrogen. In conclusion, only a few cases did proline known as compatible solute constitute a significant proportion of the free amino acid pool in coastal plants.

• Preventive Nutrition and Food Science
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• v.15 no.2
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• pp.120-129
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• 2010

To elucidate the composition of extractive nitrogenous components in the fresh Capsosiphons fulvescens cultured off the southern coast of Korea, and to determine the monthly variation of these nitrogenous components, extract samples collected monthly from December to March at Jangheung-gun, Jeonnam Province were analyzed for total nitrogen, free and combined amino acids, ATP and related compounds, betaines, trimethylamine oxide (TMAO) and trimethylamine (TMA). The content of extractive nitrogen was 1,090~1,233 mg/100 g on dry basis. The number of 21~25 ninhydrin-positive substances was detected in the analysis of free amino acids, and their total amount was 3,710~4,788 mg/100 g on dry basis. Among them, free proline, asparagine, glutamic acid, alanine, taurine and glutamine were found to be abundant. The combined amino acids amounted to 1,573~2,121 mg/100 g in total and the total amount of ATP and related compound was 33.8~84.0 mg/100 g ($1.06{\sim}2.46\;{\mu}mol/g$) on dry basis. Betaine, glycinebetaine, $\beta$-alaninebetaine, $\gamma$-butyrobetaine, homarine and trigonelline were detected in most of samples. Levels of free and combined amino acids, ATP and related compounds fluctuated from sample to sample, with their contents higher in December and January and lower in March.

• Korean Journal of Food Science and Technology
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• v.3 no.1
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• pp.57-63
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• 1971

1) Among five lactic acid bacteria examined, Str. thermophilus and Str. diacetilactis produced remarkably greater amount of acids in soybean milk than Str. lactis, Str. cremoris and L. bulgaricus. 2) Soybean milk and skimmed dry milk were combined in the ratio of 7 : 3 and were carried out in lactic acid fermentation for 24 hours at optimum temperature. The result indicated that the yield of precipitation and protein content of it were the most, the moisture content was the least and curd structure formed was considered too hard. 3) Based on these and other results, following procedure was used for manufacturing: soybean milk and skimmed dry milk were combined in the ratio of 7 : 3, heated at $121^{\circ}C$ for 20 min., cooled, added Str. thermophilus as lactic acid starter and incubated for 24 hours and $37{\pm}1^{\circ}C$. The curd was cooked, hooped, and pressed for 24 hours, to the surface of which, Penicillium caseicolum and sodium chloride were spread. During ripening of the curd at $15^{\circ}C$ and $85{\sim}90%$ RH for 21 days, Pen. caseicolum was highly developed after 7 days, pH was increased and proteolytie activity has reached to the peak point after 14 days. After 7 days of ripening total water soluble nitrogen, water soluble protein nitrogen and amino acids nitrogen were begun to increase. After 21 days of ripening total water soluble nitrogen, water soluble protein nitrogen and amino-N reached to 52%, 32% and 14% of total nitogen. In the soybean cheese, after 21 days of ripening, 17 or more kinds of amino acids were detected by two-dimentional paper chromatography. The product contained 63.2% of moisture, 17.5% of crude protein, 13.2% of crude fat, 2.8% of crude ash and 2.5% of sodium chloride.

• 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 Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.650-655
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• 2017

Extraction methods for cultured sea mussels Mytilus edulis and the quality characteristics of resulting extracts were investigated. The crude protein, carbohydrate and volatile basic nitrogen content of raw sea mussels was 15.2%, 1.9%, and 11.2 mg/100 g, respectively. Extracts were prepared using three different methods: hot-water extract (WE), scrap enzymatic hydrolysate extraction (SE), and complex extraction (CE). The respective extracts contained 5.5%, 8.6%, and 6.6% crude protein; 281.7, 366.0, and 343.0 mg/100 g amino nitrogen,: and 2.0%, 1.1% and 1.8% salinity. Their extraction yields were 689, 323, and 1,012 mL/kg. The CE method was superior to the traditional WE method in terms of extraction yield, amino-nitrogen content, and organoleptic qualities, but not odor. Active taste components were evaluated and the total free amino acid content of the WE and CE methods was 5,667.0 and 7,006.3 mg/100 g, respectively. The concentrations of major components (for WE and CE methods, respectively) were as follows: glutamic acid (1,244.0 and 955.4 mg/100 g), taurine (987.9 and 746.8 mg/100 g), glycine (721.2 and 847.0 mg/100 g), alanine (341.9 and 423.8 mg/100 g), arginine (265.5 and 376.5 mg/100 g), lysine (199.8 and 270.4 mg/100 g), and proline (253.9 and 220.3 mg/100 g). In conclusion, these results demonstrate that there is potential for using the CE method to expand the commercial utilization of sea mussels as a flavoring substance resource.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.1
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• pp.45-51
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• 2009

In this study, food protein hydrolysates were prepared from six types of food protein: purified meat protein, whole egg protein, casein, isolated soy protein, concentrated rice protein, and gluten. Food proteins were hydrolyzed with pepsin and ethanol (80%)-soluble fractions of pepsin hydrolysates were employed for analysis. The products were colorless and odorless powders with low fat content and good solubility. The MW (molecular weight) of the protein hydrolysates was confirmed to be $200{\sim}1,800$ via gel filtration. Free amino acid contents accounted for less than 5% of the samples. The results of our amino acid analysis revealed that all food protein hydrolysates preserved their original amino acid compositions and nutritional values of their source proteins with highly pure oligopeptide mixtures. These results show that the food protein hydrolysates prepared in these investigations should prove excellent dietary nitrogen sources for a variety of applications.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.5
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• pp.667-676
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• 2012

This study was conducted to investigate the quality characteristics and antioxidant activity of Kochujang following the addition of deodeok (Condonopsis lanceolata) powder. To accomplish this, 1%, 3% and 5% deodeok powder was added to Kochujang and the samples were then incubated at $30^{\circ}C$. during which time the general ingredients, water content, acidity, salinity, reducing sugar content, amino-nitrogen content and DPPH were analyzed at intervals of about two weeks. The water crude protein, crude fat and ash content were 3.61%, 8.44%, 4.62% and 8.85%, respectively. The initial acidity was 3.23~3.97%, and this increased to 4.39~44.86%. highlight please clarify this, I cannot infer your intended meaning; however, this can likely be deleted. The salinity was 7.42~7.73%, and 5% with deodeok powder producing the lowest content and showing a tendency to decrease during the storage period. The early amino-nitrogen content was 274.0~333.1%, with higher nitrogen contents being associated with large amounts of deodeok powder. The amino-nitrogen content during the storage period increased to the 4th week, then decreased. Additionally, the a value decreased sharply during the 4-week storage period. Addition of large amount of deodeok powder significantly improved the free radical scavenging activity. The free radical scavenging activity of 1%, 3% and 5% deodeok powder was higher than that of Kochujang throughout the maturation period. Overall, the results of this study indicate that there is the potential to develop functional foods by the addition of deodeok.

• Korean journal of food and cookery science
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• v.12 no.3
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• pp.273-278
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• 1996

To investigate the main components of Korean traditional soy sauce for its typical taste, we compare the physicochemical properties of Korean traditional soy sauce and commercial soy sauce. The physicochemical analysis revealed that each components showed significant difference between Korean traditional soy sauce and commercial soy sauce. The significant characters for discrimination between Korean traditional soy sauce and commercial soy sauce were salt content, ammonia nitrogen content and total acidity (R$^2$=0.99). The components of Korean traditional soy sauce divided into 3 clusters, and each group is characterized as formol nitrogen, salt and total nitrogen content by cluster analysis. Main amino acids of Korean traditional soy sauce were alanine, glutamic acid, leucine and valine.