• Korean Journal of Environmental Agriculture
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• v.35 no.2
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• pp.104-110
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• 2016

BACKGROUND: There is lack of comprehensive compositional data of the amino acid profile of spinach with regard to different cultivars. A more detailed knowledge in this aspect will be of benefit in the future selection of spinach genotypes with improved nutritional quality.METHODS AND RESULTS: The effects of cultivar type (Jeoncheonhu, Sagyejul, Namdongcho and Mustang) and harvest time (79^th, 116^th and 145^th days after sowing or DAS) on the concentrations of free amino acids in field-grown spinach (Spinacia oleracea) were examined. About 35 different free amino acids were detected and quantified by the amino acid analyzer. Glutamic acid and proline were identified as the major amino acids, while α -aminoadipic acid and α-aminobutyric acid were present in much lower concentrations. Spinach constituted 1468.4 mg/100 g total free amino acids (TAA), of which essential amino acids, neutral/acidic amino acids and sulphur containing amino acids constituted around 15, 45 and 2% of the TAA, respectively. The most limiting amino acids among the leafy vegetables - cysteine was recorded only in Mustang harvested at 116 DAS. Free amino acid contents did not differ significantly among the spinach cultivars and also at different harvest times.CONCLUSION: The data show that, either of the spinach cultivars, preferably Mustang harvested on or after 116 DAS can serve as a significant source of nutritionally relevant amino acids to meet the demand of the growing populations.

• Journal of the Korean Society of Food Science and Nutrition
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• v.12 no.2
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• pp.146-149
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• 1983

An experiment was made to investigate the effect of acid and alkali treatments obfserving the amount of nutrients especially calcium(Ca), phosphorus(P), ${\alpha}$-amino nitrogen(${\alpha}$-amino N), and total nitrogen(total-N)which were extracted from beef bone. 0~0.8% acetic acid and 0~0.5% sodium bicarbonate were used for treatment on different levels. The results are as follows; In case of acid treatment, Ca and P contents in bone stock wer observed to increase significantly according to acid concentration. Ca and P contents in bone stock highly incrased especially when the acid concentration was above 0.3%. Ca and P ratio varied from one to two when the acid concentration was below 0.01%. However contents of ${\alpha}$-amino N and total-N increased significantly when acid concentration was above 0.5%. In case of alkali treatment, contents of Ca and P did not increased significantly on all levels of sodium bicarbonate. The content of ${\alpha}$-amino N, however, increased significantly when the alkali concentration was in 0.05% but total-N did not show any variation in amount. These results suggest that acid treatment can give rise to an increase of the amount of nutrients which are extracted from beef bone but alkali treatment does not.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.338-342
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• 1994

Amino acids of Pleurotus ostreatus in various cultural media(rice straw, sawdust and cotton waste) were analyzed to recognize the compositional differences depending on pileus size and portions(pileus and stipe) Total amino acids of rice straw were a little less than that of sawdust and cotton waste. Seventeen amino acids were identified and quantified. Among the amino acids glutamic acid was higest and cystine was lowest. The amino acid contents depending on the pileus size was higest in $3{\sim}7\;cm$ of rice straw, under 3 cm of sawdust, over 7 cm of cotton waste, respectively. The content of them was found to be higher in pileus than stipe.

• Journal of Food Hygiene and Safety
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• v.19 no.1
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• pp.31-37
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• 2004

This study was performed to investigate the changes of amino nitrogen, total amino acids, free amino acids, and cole. of traditional Korean soybean paste (doen-jang) during the ripening and storage for 12 months. All of the preparation methods for soybean paste followed the recommendations of the Korea Food Research Institute. The components of soybean paste were analyzed at 0, 6, and 12 months. The content of amino nitrogen of soybean paste was significantly higher than that of soybeans or meju (soybean cakes) at the initial stage of storage (p〈0.05), and decreased during the storage. The composition of total and free amino acids and their ratios of soybean paste were changed during the storage. The ratios of free to total amino acids of soybeans, meju, and soybean paste were 0.8%, 17.3%, and 20.4∼32.9%, respectively. Glutamic acid, which represents the savory taste, was detected the most abundantly in soybean paste during the storage. The ratios of free to total amino acids of glutamic acid were 21.1∼41.5% in soybean paste. Lightness, redness and yellowness of Hunter color of soybean paste decreased over time (p〈0.05). The results of this study indicate that the ratios of fee to total amino acids of soybean paste were much higher than those of soybeans, although its contents of total amino acids were much lower than those of soybeans. The results also indicate that this comes from the preparation and fermentation of meju. It was suspected that the organoleptic quality of soybean paste derived from these three components might be inferior over 1 year of storage time.

• Biotechnology and Bioprocess Engineering:BBE
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• v.8 no.6
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• pp.368-372
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• 2003

The growth and amino acid contents of the cyanobacterium, Spirulina platensis strain NIES 46, were investigated using ammonium, nitrate, nitrite, or urea as the sole nitrogen source in a batch culture. Chlorophyll a concentration was highest at 2,096$\mu\textrm{g}$/L in the nitrate group after 10days of cultivation, while the dry weight of S. platensis was highest at 4.5g/L in the ammonium group after 30days of cultivation. The total amino acid content was highest at 174mg/g dry weight of S. platensis in the urea group at the end of the cultivation period, yet the amino acid patterns for S. platensis were similar for all the experimental groups. Therefore, it seemed that the growth and amino acid composition of S. platensis varied depending on the type of nitrogen sources, while the amino acid patterns were not changed. Also, the most efficient harvesting time for S. platensis seemed to be approximately 10 days after cultivation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.6
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• pp.573-580
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• 2010

The study investigated the effect of diets supplemented with different levels (0 and 2.5%) of yuza (Citrus junos Sieb ex Tanaka) on the nutritional characteristics of eels (Auguilla japonica). Fish ($9.8{\pm}1.3g$) was fed to apparent satiation twice daily for 8 months. There were no significant differences in proximate composition among the treatment groups, except for the ash and carbohydrate contents (P<0.05). The vitamin C content of eel muscle in the yuza-added group was two-times higher than in non-added groups (P<0.05). Among eight organic acids in eel muscle, lactic acid was predominant, followed by citric acid, oxalic acid, malic acid, and acetic acid. Eels fed a 2.5% yuza diet had the highest lactic acid content in all groups. Six sugars were found in all groups and glucose was the major sugar. Glucose and maltose were the dominant sugars in the yuza-added group. The abundant fatty acids in the yuza-added group were C18:1 n-9, C16:0, and C16:1 n-7, which comprised over 80% of the total fatty acids. The major amino acids in samples were glutamic acid, aspartic acid, lysine, and leucine. There were few differences in the free amino acid compositions among the groups. However, histidine was the predominant amino acid and constituted over 53% of the total free amino acids.

• Journal of Mushroom
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• v.18 no.2
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• pp.164-173
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• 2020

The extracts of four species of ectomycorrhizal mushrooms-Cantharellus cinnabarinus (OK1247), Lactarius parallelus (OK1264), Tricholoma matsutake (OK1282), and Ramaria botrytis (OK1283)-were prepared to determine their antioxidant activities and nutritional properties. R. botrytis extract displayed the highest 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (33.8%), ferric reducing antioxidant power (0.38), reducing power (0.35), total polyphenol (13.83 mg gallic acid equivalent/g), and flavonoid contents (2.56 mg quercetin equivalent/g). L. parallelus extract displayed the highest nitrite scavenging activity. Analysis of amino acid contents revealed that C. cinnabarinus extract had the highest total amino acid (1,046.1 mg/kg) and essential amino acid (404.9 mg/kg) contents, while R. botrytis extract had the lowest total amino acid (708.3 mg/kg) and essential amino acid (247.3 mg/kg) contents. Among the amino acid components detected in the four ectomycorrhizal mushrooms, cysteine was the most abundant, accounting for 14.3~20.7%, followed by phenylalanine, which accounted for 9.5~13.4% of all amino acids. In summary, the antioxidant activities were the highest in R. botrytis extract, and the amino acid content was the highest in C. cinnabarinus extract, among the four ectomycorrhizal mushrooms.

• Journal of Sericultural and Entomological Science
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• v.21 no.2
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• pp.7-10
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• 1979

Purified preparations of flacherie virus capsid protein were fractionated by SDS-polyacrylamide gel electrophoresis, and amino acid composition was determined by amino acid analyzer. Three polypeptide components, FP I, FP II and FP III were detected, and the molecular weights of these components were 37,500, 30,500 and 26,500 respectively. The FP III was major poly-peptide comprised about 68.4% of the total virus capsid protein. Seventeen amino acids were detected by an amino acid analyzer from hydrolyzate of the virus capsid protein and the pattern of amino acid composition was similar to those of several other insect viruses.

• Journal of Ginseng Research
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• v.14 no.1
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• pp.21-26
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• 1990

The chemical composition and stabilities of the purified ginseng invertase were investigated. The purified enzyme was found to be a glycoprotein composed of 80.2% protein and 19.7% total sugar. The protein component of the enzyme was composed of acidic amino acid (9.3%), basic amino acid (48.9%), nonpolar amino acid (21.4%), polar amino acid (20.4%) and 6.1% S-containing amino acid. It showed especially high contents of histidine and serine. The enzyme was inactivated almost completely by the treatment with some proteases (papain, pepsin. trypsin, pancreatin and microbial alkaline pretense) and protein denatllrants (8M urea and 6M guanidine-HC1), bolt not with glyrosidase (${\alpha}$-amylase, ${\beta}$-amylase. glcoamylese and cellullase). btonosaccharides sllch as glilrose, fructose, galactose and mannose did not exert any influence on the enzyme activity. The activity of the enzyme was inhibited by Ag+, Mn2+, Hg2+, Zn2+ and Al3+, whereas Ca2+, Mg2+, Ba2+ and Fe3+ gave rather activating effects on the enzyme activity. The enzyme was relatively stable in the VH range of VH 6 and 8, and at the temperatures below 35$^{\circ}C$.

• Korean Journal of Food Science and Technology
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• v.54 no.2
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• pp.228-234
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• 2022

Various types of tea have been cultivated to obtain different flavors and enhance their functional properties. The objective of this study was to investigate the physicochemical properties of γ-aminobutyric acid (GABA) teas produced from commercial Korean green, white, and black teas. The concentration of total minerals was reduced in GABA green tea and GABA white tea but was improved in GABA black tea. The essential, non-essential, and total free amino acid contents were remarkably increased in the GABA teas. The amino acid GABA content was increased by 561.00 and 294.20 times in GABA white tea and GABA black tea, respectively. The antioxidant potential was not reduced, although the total polyphenol and total flavonoid contents decreased in GABA green tea and GABA black tea. The results indicated that the overall nutritional value of commercial green, white, and black teas could be improved by processing them into GABA teas.