• Polymer(Korea)
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• v.29 no.5
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• pp.518-521
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• 2005

Biodegradable polymers and hydrogels have been increasingly applied in a variety of biomedical applications including current drug delivery system and tissue engineering field. ${\alpha},\;{\beta}-Poly$(N-2-hydroxyethyl-DL-aspart-amide), PHEA. is one of poly(amino acids) with hydroxyethyl pendants, which is hewn to be biodegradable and potentially biocompatible. So that, the utilization and various chemical modifications of PHEA have been attempted for useful biomedical applications. In this wort chemical gels based on PHEA were prepared by crosslinking with diisocyanate compound in DMF in the presence of catalyst. Here, the PHEA was prepared from polysuccinimde, the thermal polycondensation product of aspartic acid, via ring-opening reaction with ethanolamine. The preparation of gels and their swelling behavior, depending on the different medium and pH, were investigated. Also the morphology by SEM and simple hydrolytic degradation were observed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.542-549
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• 2013

This study was conducted to investigate the chemical properties and functionality of probiotic potato juice fermented by Lactobacillus casei. Free sugar content (especially glucose) of potatoes decreased by fermentation, but organic acid contents increased by fermentation. Although the free amino acid content of Superior juice significantly decreased after fermentation, Haryeong significantly increased after fermentation. ${\gamma}$-Aminobutyric acid, a functional amino acid, was detected at high levels in all samples and slightly decreased with fermentation, but not significantly. The total polyphenol content of potato juice showed insignificant changes in all samples by fermentation. The hydroxyl radical scavenging activity of all samples was more than 90%, and most of the activity was maintained after fermentation. The nitrite scavenging ability of all samples greatly decreased with fermentation; however a SOD-like activity slightly increased with fermentation, except for Haryeong. There was a significant xanthine oxidase inhibitory effect in fresh potato juice (more than 45%) and a low loss by fermentation. From our results, most of the chemical properties and functionality of potato juice are maintained after fermentation, although free sugar content and nitrite scavenging activity decline. Thus probiotic potato juice fermented by lactic acid could be used as a functional beverage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.4
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• pp.370-374
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• 1985

To investigate the flavor components of sun-dried ray, Raja porasc, the contents of such as free amino acids, nucleotides and their related compounds, total creatinine, betaine, TMAO, fatty adds, and volatile compounds were analysed. The content of total free amino acids was 1773.3mg% on dry basis and the abundant amino acids were taurine, lysine, leucine, alanine, glycine, glutamic acid, proline, and valine in order and these amino acids accounted for 80% of total free amino acids in sun-dried ray. In the nucleotides and their related compounds, hypoxanthine was the most abundant. Ammonia-N was the most abundant, resulting 26.4% of extractive nitrogen which was 1965.6mg% and next free amino acid-N, total creatinine-N, and nucleotide-N in order. In the fatty acid composition of total lipid and neutral lipid, polyenoic acid was abundant holding 42.0%, 45.3% respectively. In phospholipid, the ratio of polyenoic acid and saturated fatty acid were similar to 39% respectively. The predominant fatty acids in total lipid, neutral lipid, and phospholipid were $C_{16:0},\;C_{22:6},\;C_{18:1},\;C_{18:0},\;and\;C_{20:4}$. In the volatile compounds, isocaproic acid, caproic acid, isobutyric acid, and butyric acid were the major portion of the 8 kinds of volatile fatty acids detected and 2-butanone, pentanal, and 2-methylpropanal were the major portion of the 8 kinds of volatile carbonyl compounds detected and also trimethylamine was the major portion of 2 kinds of volatile amines detected. It was presumed from the results that the reciprocal action of taste compounds such as free amino acids, nucleotides and their related compounds total creatinine, betaine, and TMAO and volatile compounds such as volatile carbonyl compounds, volatile fatty acids, volatile amines, and ammonia played an important role for the characteristics of flavor of sun-dried ray.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.6
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• pp.893-900
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• 2014

The aim of this study was to investigate physicochemical changes in Salvia plebeia R. Br. (SPA) upon hot-air drying and blanching. After hot-air drying and blanching, total polyphenol and flavonoid contents were reduced from 96.64 mg and 48.40 mg gallic acid equivalent/g to 29.70 mg and 22.10 mg quercetin equivalent/g, respectively. DPPH radical scavenging activities at $25{\mu}g/mL$ of SPA were 94.5% for ascorbic acid, 84.3% for hot-air dried SPA, and 59.7% for blanched SPA and there was no significant difference between those of hot-air dried SPA and ascorbic acid as a positive control. Total sugar contents were 7.187% and 6.104% for hot-air dried SPA and blanched SPA, respectively. During the blanching process, sucrose and maltose contents decreased, whereas glucose and fructose contents increased. Glucose and fructose were converted into citric acid in blanched SPA, whereas sucrose and maltose were converted into tartaric acid, malic acid, and succinic acid. Fourteen kinds of amino acids were found, but methionine, lysine, glycine, histidine, and cysteine were absent. The proportion of essential amino acids was 61.76% upon hot-air drying, which was a relatively high amount. In addition, hot-air drying resulted in 1.40 mg/100 g of norvaline as well as 39.00 mg/100 g of GABA, which are non-amino acids. Therefore, Salvia plebeia R. Br. can be used not only as vegetables but also as highly useful and various health functional foods with antioxidant effects and excellent nutrition.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.12
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• pp.1799-1805
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• 2015

Rice vinegar (RV) is primarily made from fermented rice or rice wine in Korea, China, and Japan. Ten commercially available naturally-fermented rice vinegars produced in Korea (KRV1~4), China (CRV1~2), and Japan (JRV1~4) were comparatively investigated for their physicochemical properties and antioxidant activities. KRV showed a significantly higher total acidity range (5.07~6.27) than both CRV (4.67~4.84) and JRV (4.64~4.84). These acidity ranges corresponded with respective standards of each country: Korea (Food Code), China (GB), and Japan (JAS). Six different organic acids were detected in RVs; acetic acid and succinic acid were the most prominent. Thirty different amino acids were detected in RVs, and main identified amino acids were alanine (KRV), phenylalanine and aspartic acid (CRV), and leucine and alanine (JRV). ${\gamma}-Aminobutyric$ acid was detected at high concentration in KRV1. KRV1 showed maximum total phenolic content, and DPPH and ABTS radical scavenging activities of samples were also determined with significantly increasing tendency. KRV1 (produced from brown rice with aging period of >1 year) exhibited the highest free amino acid content and antioxidant activity as compared to CRV and JRV.

• Food Science and Preservation
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• v.14 no.6
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• pp.709-715
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• 2007

Korean green tea has been claimed to have health-promoting effects, which may be related to the antioxidant activity in vitro. Korean green teas (Woojeon, WJ ; Sejak, SJ ; Jungjak, JJ ; Daejak, DJ) were subjected to different harvested times and yet little research has examined their bioactive compounds. To assess the effect of this different harvested times on nutritional and health-related properties such as Korean green tea polyphenols, flavonoids, theanine and free amino acids, antioxidant activities and radical scavenging activities were determined. Total polyphenols in JJ (37.16 mg/g) was higher than in other products (WJ, 19.55 ; SJ 24.65 ; DJ, 23.28 mg/g). Contents of flavonol and flavone glycosides were the highest at DJ (350.83 mg%) as compared to WJ (220.81), SJ (256.88) and JJ (270.36 mg%). Contents of theanine and total free amino acids were the highest at WJ (14.11, 23.62 mg/g, respectively), but decreased thereafter. Antioxidant activities were higher in JJ and DJ, using the linoleic acid peroxidation, DPPH and ABTS free radical-scavenging activities. However, WJ and SJ had less active antioxidant activity and free radical-scavenging activity. Reducing powers were increased depend on the concentration of extracts. Antioxidant activity and free radical-scavenging activity of JJ and DJ seemed to relate with total polyphenol and flavonoid contents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.8
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• pp.1015-1021
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• 2007

To expand the use of rainbow trout, the preparation of canned rainbow trout was conducted and the characteristics were also examined. Canned boiled rainbow trout was low in moisture, while high in lipid and ash compared to commercial canned salmon. There was no difference in the protein content between two kinds of canned fish. The contents of free amino acid and total amino acid of canned boiled rainbow trout were 330.9 mg/100 g and 18.2 g/100 g, respectively, and the major amino acids were glutamic acid (68.6 mg/100 g) and anserine (124.1 mg/100 g) in free amino acid and glutamic acid (18.0%), aspartic acid (8.6%), lysine (8.4%) and leucine (8.9%) in total amino acid. The mineral contents of canned boiled rainbow trout were 123.3 mg/100 g for potassium, 271.3 mg/100 g for calcium, 40.3 mg/100 g for magnesium, 2.4 mg/100 g for ferrous and 244.3 mg/100 g for phosphorus. The fatty acid composition of canned boiled rainbow trout was the highest (43.7%) in polyenoic acid, followed by monoenoic acid (28.8%) and saturated acid (27.5%) and their main fatty acids were 16:0 (18.4%), l8:1n-9 (20.6%), l8:2n-6 (17.3%) and 22:6n-3 (12.7%), respectively.

• KSBB Journal
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• v.23 no.5
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• pp.387-391
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• 2008

Green tea is popular plants in Asian countries and has become more widespread in western countries due to its taste characteristics and health benefits. Apart from green tea leafs, however, the use of root and seed of green tea tree has not intensively been investigated yet. In this study, the contents of mineral, vitamin, total amino acid, free amino acid, and total polyphenol (catechin, caffeic acid, and chlorogenic acid) of the root and seed of green tea tree were analyzed for the development of healthy foods. For minerals, potassium contents were 1,052 and 1,480 mg/100g-dry weight of root and seed, respectively. The order of mineral contents were as follows: K > P > Ca > Mg > Na > Fe > Mn > Zn > Cu in root and K > P > Na > Ca > Mg > Mn > Fe > Cu > Zn in seed. For vitamins, vitamin C contents were 5.72 and 6.05 mg/100g-dry weight of root and seed, respectively. The presence of more various kinds of vitamins were observed in seed than in root. For total amino acids, the contents were 1,651 and 4,335 mg/100g-dry weight of root and seed, respectively. The total amino acid contents of seed and root were higher than those in commercial green tea products. Especially the phenylalanine contents were 16 and 139 mg/100g-dry weight of root and seed, respectively whereas phenylalanine was not found in commercial green tea products. Concerning free amino acids, the bitter tasting amino acids such as arginine, valine and tryptophan were more abundant in root and the sweet tasting ones such as glutamic acid, alanine, aspartic acid, and serine were more abundant in seed. The total polyphenol contents were 237 and 81 mg/100g-dry weight of root and seed, respectively. The polyphenol contents in root were three times higher than that in seed so root may be a better source for antioxidant ingredients than seed. Among many polyphenols, catechin, caffeic acid, and chlorogenic acid were the top three major components.

• Food Science and Preservation
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• v.24 no.5
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• pp.697-706
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• 2017

The purpose of this study was to investigate the physiochemical properties of Doenjang was fermented by added with fungi and protease. The moisture content and pH of Doenjang added with protease (WP) were lower than those of control w/o protease while the contents of titratable acidity, reducing sugar, and amino-type nitrogen in WP were higher than control. The ${\alpha}$-amylase activities of Doenjang added with single and mixed Protease B were the highest at 4 weeks of fermentation period and protease activity of WP was about 4 times higher than that of control. The 4-9 kinds of free amino acids (proline, isoleucine, leucine, and phenylalanine etc.) in WP was increased in comparison with control. The DPPH radical scavenging activity and total polyphenol content were higher in WP than control. Total aerobic bacterial and fungal numbers were decreased depending on fermentation time regardless of addition of protease. In conclusion, the protease can be used as additives improving the quality and taste of fermented Doenjang.

• Korean Journal of Food Science and Technology
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• v.52 no.1
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• pp.94-102
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• 2020

Brown rice Makgeolli was brewed by using the Saccharomyces cerevisiae strain SRCM102596 under different fermentation conditions: temperatures at 20 and 25℃ and Nuruk ratios of 5, 10, and 15%. There were no significant differences in the pH and total acidity between samples. The alcohol content at the different nuruk ratios varied significantly by the days in the fermentation process. The major free sugars were maltose, glucose, and fructose, and they gradually reduced with fermentation. The major organic acids in the brown rice Makgeolli were oxalic acid, citric acid, malic acid, succinic acid, and acetic acid. The lactic acid content increased with the number of days in the fermentation process. Among the 24 different free amino acid contents identified, the total free amino acid content of, especially, threonine, serine, and alanine were high in the brown rice Makgeolli, at 20℃ and nuruk ratio of 10%.