• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.348-355
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• 1999

Effects of pH, sugars, organic acids, metal ions, ascorbic acid and light on the stability of anthocyanin pigment extracted from purple-fleshed potato (Solanum tuberosum L.) were studied. The pH had marked influences on the color of the potato anthocyanin pigment: i.e., the lower the pH of the anthocyanin solution was, the more stable and intenser of the pigment was. It showed characteristic bathochromic shift as the pH of the solution increased. Generally, the addition of sugars into the purple-fleshed potato anthocyanin solution caused decrease in color stability of the pigment. Among the sugars tested, maltose was the most deleterious followed by sucrose, galactose, fructose and glucose. The addition of organic acids greatly increased the stability of the pigment. Malic acid was found to be the most effective in stabilizing the pigment followed by tartaric, citric and succinic acids, while malonic acid was found to be deteriorative to the stability of the pigment. Most metal ions except $Cu^{2+}$ increased stability of the pigment-especially, $Cd^{2+}\;and\;Al^{3+}$ were more effective than the others. Ascorbic acid degraded the pigment considerably, but the adverse effect was diminished by adding thiourea. Light gave an adverse effect to the stability of the purple-fleshed potato anthocyanin pigment, which could be minimized by shielding the light from the pigment.

• Current Research on Agriculture and Life Sciences
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• v.9
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• pp.51-59
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• 1991

This study was conducted to understand browning characteristics of Chinese Chestnut during processing and storage. For this, the isolation and identification of polyphenolic compounds and the biochemical characteristics of polyphenol oxidase(PPO) were investigated. The content of total phenol was $6.5{\mu}g/g$ and it was consisted of ferulic acid, caffeic acid, synapic acid, p-coumaric acid, gallic acid and salicylic acid in order. PPO was purified 11.7 fold through ammonium sulfate fractionation, DEAE-cellulose column chromatography and Sephadex G-200 column chromatography. Purified enzyme showed single protein and activity band by polyacrylamide gel electrophoresis. The optimum pH and temperature of PPO were 5.9 and $45^{\circ}C$, respectively. The activity of PPO was lost 93% by exposing at $80^{\circ}C$ for 15minutes. $Mg^{{+}{+}}$, $Ca^{{+}{+}}$, $Zn^{{+}{+}}$ increased the activity of PPO, but $Fe^{{+}{+}}$, $K^+$, $Hg^{{+}{+}}$ inhibited PPO at 10mM concentration. L-ascorbic acid, thiourea, sodium chloride and L-cysteine were effective inhibitors of PPO. The activity of PPO was higher for o-diphenols than other polyphenols. The Km value of PPO for catechol was 5mM.

• Proceedings of the Korean Society of Life Science Conference
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• 2002.03a
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• pp.82-82
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• 2002

• Proceedings of the Korean Society of Life Science Conference
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• 2000.09a
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• pp.21-21
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• 2000

• Journal of Environmental Science International
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• v.23 no.11
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• pp.1791-1799
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• 2014

This study was conducted to evaluate the contents of antioxidative components from pulpy and seed in wild haw (Crataegus pinnatifida $B_{UNGE}$). Pulpy and seed of haw were smashed, then measured for color properties, antioxidative components of ascorbic acid, phytic acid, proanthocyanidin, anthocyanin, total carotene, ${\beta}$-carotene, lycopene, chlorophyll a, b and tannin. The $a^*$, $b^*$ and $C^*$ values of seed were significantly lower than pulpy, but $L^*$ and $H^{\circ}$ values were higher than that of pulpy. Ascorbic acid contents of pulpy and seed were found to be $10.89{\pm}1.69mg/100g$ and $1.45{\pm}0.16mg/100g$, respectively. Phytic acid, proanthocyanidin, total carotene and tannin contents of pulpy and seed were $689.17{\pm}3.63mg/g$, $597.78{\pm}2.93mg/g$; $355.61{\pm}19.39mg/g$, $49.12{\pm}4.97mg/g$; $8.32{\pm}0.42mg%$, $0.80{\pm}0.01mg%$; $7.53{\pm}0.09mg/g$, $1.02{\pm}0.03mg/g$, respectively. Similarly, ${\beta}$-carotene, lycopene, chlorophyll a and chlorophyll b contents of pulpy also displayed higher values than that of seed. On the contrary, anthocyanin content of seed ($4.24{\pm}0.33mg/L$) was remarkably higher than pulpy ($0.99{\pm}0.62mg/L$). The results showed that pulpy could be severed as great natural antioxidant and biohealth functional food.

• BMB Reports
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• v.32 no.5
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• pp.451-455
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• 1999

The concentrations of L-ascorbic acid (AsA, ascorbate, vitamin C) and its biosynthetic and metabolically-related enzymes such as L-galactono-1,4-lactone dehydrogenase (GLDase), ascorbate peroxidase (APX), and ascorbate oxidase (ASO) were investigated in suspension cultures of Scutellaria baicalensis. Cells growing from 4 days after subculture (DAS) to 9 DAS and from 16 DAS to 19 DAS showed a diauxic growth, and then growth rapidly decreased with further culturing. The AsA content slowly increased to 19 DAS, reached a maximum at 21 DAS (ca $120\;{\mu}g/g$ dry cell wt), and then rapidly decreased with further culturing. GLDase and ASO activity were well correlated with the cell growth curve, showing a maximum at 19 DAS, whereas APX activity showed a good correlation with the changes in AsA content, showing a maximum at 21 DAS. The total ascorbate contents (reduced form, AsA, and oxidized form, dehydroascorbate, DHA) were markedly enhanced at 10 DAS when L-galactose and L-galactono-1,4-lactone (25 mM) were added to SH medium supplemented with 20 g/l sucrose at 9 DAS, by 5.5 and 6.8 times, respectively. DHA composed more than 90% of the total ascorbate contents in suspension cultures of S. baicalensis, even though the ratio of reduced to oxidized form slightly varied with cell growth stage. The results indicate that L-galactose and L-galactono-1,4-lactone are effective precursors of AsA in cell cultures of S. baicalensis, and that in vitro cultured cells provide suitable biomaterials for the study of biosynthesis and metabolism of AsA.

• Journal of Ginseng Research
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• v.23 no.3 s.55
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• pp.176-181
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• 1999

The purpose of this study was to investigate the antioxidant activities of water soluble browning reaction products (WS-BRPs) isolated from korea red ginseng. Antioxidant activities of WS-BRPs were examined with the various systems. All three WS-BRPs (L, S-1 and S-2) were found to have an ability to donate hydrogen to DPPH. Especially, L was more effective than S-1, S-2. and, L as well as S-1 and S-2 was the strongest than BHT, BHA $(5{\times}10^{-4}M),\;{\alpha}-tocopherol\;(1.0{\times}10^{-4})$ and ascorbic acid $(5.7{\times}10^{-3}M)$ previously known as antioxidants. These WS-BRPs (L, S-1 and S-2) also showed a synergistic effect against antioxidative activities of these antioxidants. Moreover S-2 had the strongest activity of these three WS-BRPs to scavenge free radicals such as hydrogen peroxide $(H_2O_2)$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.8
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• pp.1252-1256
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• 2004

Radiolytic characteristics of phytic acid by gamma irradiation were investigated, and the antioxidative activity between irradiated phytic acid and commonly used antioxidants including ascorbic acid, tocopherol and butylated hydroxyl anisole (BHA) was evaluated. Phytic acid sodium salt dissolved in a deionized distilled water was irradiated at 0, 5, 10, 15 and 20 kGy. It was found that the level of irradiation had an effects on the degree of degradation. After irradiation, stable DPPH radical scavenging capacity of phytic acid was newly observed, and it was significantly increased by dose-dependent manners (p<0.05). Antioxidant activity of phytic acid in the oil models was higher than that of the other antioxidant during storage, and phytic acid (400 $\mu\textrm{g}$/mL) irradiated at 20 kGy especially showed the highest antioxidative ability among the antioxidants tested during 3 weeks. Results indicated that irradiation induced the radiolysis of phytic acid in an aqueous model system, and the antiradical and antioxidative activities of irradiated phytic acid increased.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.217-225
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• 2004

This study was carried out to reduce the loss of frozen dough quality during frozen storage. Using response surface method, ascorbic acid 160.4 ppm, L-cysteine 63.1 ppm, and SSL 0.6% were found to be optimum, with xanthan gum 0.3% (formula A) and Ultra tex-3 5% (formula B) added as cryoprotectants. During frozen storage at $-20^{\circ}C$, control rapidly deteriorated after 4 weeks, while formulas A and B showed slight deterioration with immutable quality after 10 weeks.

• Journal of Electrochemical Science and Technology
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• v.8 no.4
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• pp.274-281
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• 2017

This paper describes the simple fabrication of an electrode modified with electrochemically reduced graphene oxide (ERGO) for the simultaneous electrocatalytic detection of dopamine (DA), ascorbic acid (AA), and uric acid (UA). ERGO was formed on a glassy carbon (GC) electrode by the reduction of graphene oxide (GO) using linear sweep voltammetry. The ERGO/GC electrode was formed by subjecting a GO solution ($1mg\;mL^{-1}$ in 0.25 M NaCl) to a linear scan from 0 V to -1.4 V at a scan rate of $20mVs^{-1}$. The ERGO/GC electrode was characterized by Raman spectroscopy, Fourier transform infrared spectroscopy, contact angle measurements, electrochemical impedance spectroscopy, and cyclic voltammetry. The electrochemical performance of the ERGO/GC electrode with respect to the detection of DA, AA, and UA in 0.1 M PBS (pH 7.4) was investigated by differential pulse voltammetry (DPV) and amperometry. The ERGO/GC electrode exhibited three well-separated voltammetric peaks and increased oxidation currents during the DPV measurements, thus allowing for the simultaneous and individual detection of DA, AA, and UA. The detection limits for DA, AA, and UA were found to be 0.46, 77, and $0.31{\mu}M$ respectively, using the amperometric i-t curve technique, with the S/N ratio being 3.