• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.spc1
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• pp.1-9
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• 1996

The edible natural pigments extracted from plant organs become steadly popular to consumer because of those physiological functions desirable for food preservation and human health in recent years. There are a number of colored rice genotypes from light brown to blackish purple via reddish brown and purple. Some researchers reported their results on extraction recipes and identification of chemical structure of the pigments from the colored rice. The pigments extracted from colored rices can be largely divided into two types of anthocyanin and tannin pigments. Anthocyanin pigments are mainly contained in purple or blackish purple rice while tannin pigments are mainly contained in brown or reddish brown rice. Some brownish purple rices showed two peaks of tannin and anthocyanin pigments simultaneously. Purple rices showed better extraction of pigments in $0.1\%$ HCl-contained $80\%$ methanol or $0.5\%$ malic-acid-contained $80\%$ ethanol, while red rices revealed better extraction of pigments in $0.01\%$ citric-acid-contained $80\%$ ethanol. The anthocyanin pigments are generally unstable to heat, light and acidity of solution. The pigments extracted from colored rice can be preserved stably under the dark and cool(<$5^{\circ}C$) condition and at pH $2.0\~4.0$. The anthocyanin pigments of purple rice are mainly composed by cyanidin-3-glucoside (chrysanthemin). The other pigment fractions in purple rice were identified to peonidin-3-gluco-side, malvidin-3-galactoside(uliginosin) and cyanidin-3-ramnoglucoside(keracyanin). The pericarp coloration of purple rices is controlled by three complimentary genes C (anthocyanin), A(activator) and $Pl^{w}$(purple leaf) genes, while the red rices are expressed by complimentary interaction between Rc(basic substance of pigment) and Rd(distribution of pigment) genes or C and $Pl^{w}$ genes. Recently, the antioxidation and antimutagenic activity in main component of anthocyanin pigments extracted from colored rice were identified. The natural pigments from colored rice can be useful for beverages, cakes, ice scream, cosmetic and so on.

• The Korean Journal of Food And Nutrition
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• v.23 no.1
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• pp.23-29
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• 2010

Pigment concentrates with violet-red color and sweet taste were obtained from purple-fleshed sweet potato(PFSP) using ethyl alcohol and water. Extract from general potato(GP) were used as a control. The relative stability of PFSP pigment concentrate(PFSPPC) in a storage test over 15 days was confirmed in the order of dark > fluorescence > sun-light irradiation. The relative stability of GP pigment concentrate(GPPC) in a storage test over 15 days was confirmed in the order of sun-light > fluorescence > dark storage. The RRP of PFSPPC was higher than that of GPPC, but the color strength of GPPC was 1/2 that of PFSPPC. Treatment of PFSPPC with aluminum potassium sulfate(0.2~0.3%, w/w) best improved its stability. The improved RRPs of PFSPPC were 45.16~47.31% in sun light irradiation, 55.91~60.22% in fluorescence irradiation, and 76.34~75.97% in dark storage conditions. In substituting aluminum potassium sulfate for chitosan, an amount of 0.2~0.3%(w/w) was suitable, giving similar results in improving pigment stability for all concentrates tested. Also, freeze-dried PFSPPC powder was manufactured as a substitute for dextrin, and also as a substitute for chitosan to the extent of 0.25%(w/w). The results of storage stabilite for freeze-dried PFSPPC and GPPC powder over 15 days, irradiation were, PRRs of 74.47~89.36% and 61.54~76.92%, respectively. The stability improving effect of freeze dried PFSPPC powder was confirmed by the results of storage experiments at various conditions. The use of freeze-dried PFSPPC powder was therefore confirmed to be an effective treatment for general foods.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.497-501
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• 1997

Kinetic parameters on heat-induced color changes of anthocyanin pigment from purple sweet potato were determined in the temperature range of $121{\sim}141^{\circ}C$. Color change determined by a browning index $(A_{532}\;nm/A_{420}\;nm)$ followed second order reaction kinetics. Activation energy values of purple sweet potato pigment solutions of pH 2.0, 3.0, 4.0 and 5.0 were 69.57, 76.68, 81.07 and 92.98 kJ/mol, respectively, indicating that temperature dependency of the reaction increased with pH. Apparent kinetic compensation effect between preex-ponential factor and activation energy value was observed.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.808-811
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• 2001

Performance of pilot plant scale extraction and concentration of purple-fleshed sweet potato anthocyanin pigment was tested and the characteristics of pigment extracts and concentrates were investigated. Fifty kilograms of purple-fleshed sweet potato was extracted with 500 L of 1% citric acid in 20% ethanol. As a whole, extraction pattern of the large scale extraction was similar to that of the laboratory scale extraction. The extracted pigment solution was filtered twice with a bag filter and a winding type microfilter and the filtrate was concentrated by a large scale vacuum evaporator at $40^{\circ}C$ and 600 mmHg vac. The mean values of total optical density (TOD) of the extract and the concentrate were 6.53 and 120.45, respectively. Browning index (BI) and Degradation index (DI) of extract were 5.86 and 1.55 and those of concentrate were 5.89 and 1.56, respectively, which indicated that the pigments were not changed or degraded through the extraction and concentration process.

• Reproductive and Developmental Biology
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• v.34 no.4
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• pp.305-308
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• 2010

In this study, we conducted an oral glucose tolerance test (OGTT) so as to compare antidiabetic activities of general potatoes, purple-flesh potatoes, and potato pigments in rats at various concentration levels. After allowing the rats to abstain from food for 12 hours, 10%/20% general potato, purple-flesh potato, and potato extract was orally administered to rats at 100 and 500 mg/kg concentrations. The blood glucose level was measured after an hour. Then, immediately, 1.5 g/kg of sucrose was administered through the abdominal cavity and the blood glucose measured after 30, 60, 120, and 180 minutes. 20% purple-flesh potato group and 10% general potato group, both 100 and 500 mg/kg, showed a significant concentration-dependent decrease in blood glucose levels after 30 minutes. The 100 mg/kg potato pigment group also showed a statistically significant decrease after 30 minutes. In conclusion, administration of 10% general potato, 20% purple-flesh potato, and potato pigment can reduce blood glucose level in an OGTT using rats.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.3
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• pp.201-206
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• 1990

The optimal cultural conditions for production of the bluish purple prgment by the cultivation of Streptomyces californicus KS-89 were determined with various substrates. The carbon and nitrogen sources on the production of pigment indicated that soluble strarch and glycerol as carbon sources and sodium glutamate sodium nitrate as nitrogen sources given a mzimum yield of the pigment at 3$0^{\circ}C$ for 7 days. The addition of ferrous sulfate was essential. The highest production of pigment was observed with cultivation in a medium containing 2.0% soluble starch 1% glycerol 0.5% sodium glutamate 0.05% sodim nitrate 0.001% L-proline 0.025% K2HPO4 0.005% MgSO4 .7H2O, 0.04% FeSO4.7H2O, 0.001% thiamine.HCl and pH7.0.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.492-496
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• 1997

Purple sweet potato pigment extract was concentrated using both membrane separation method and vacuum concentration method. The pigment extract (anthocyanin content 1.6 g/L) was concentrated $({\times}25)$ after 5 hr of continuous operation of a nanofiltration to get anthocyanin content of 10.6 g/L. Total solid content also increased continuously while the flux decreased continuously during the concentration process. Degradation index (DI) changes of concentrated pigment solution were insignificant during the whole concentration process which is indicating that the nanofiltration method does not affect color degradation of anthocyanin pigment. For the comparison test, the same pigment extract was concentrated using a rotary vacuum evaporator at temperatures of 40 and $60^{\circ}C$. At both temperatures, pigment content increased in a similar manner during concentration $({\times}5)$. However, DI value at $60^{\circ}C$ increased while that at $40^{\circ}C$ did not change appreciably. Total color difference value changed only slightly by nanofiltration and $40^{\circ}C$ while changed significantly by $60^{\circ}C$. These indicate that a membrane filtration method is more effective in concentrating purple sweet potato pigment extract than a vacuum concentration method by high temperature.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.9-14
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• 1997

The effect of freezing, thawing and blanching on the change of extractable pigment content of purple sweet potato (PSP) was investigated. Freezing at $-5^{\circ}C$ was more effective than freezing at $-20^{\circ}C\;or\;-40^{\circ}C$, and rapid thawing methods such as microwave heating or hat air blast heating were effective than slow thawing methods such as thawing at $4^{\circ}C\;or\;20^{\circ}C$. Inactivation of enzymes, which cause pigment destruction during thawing, by blanching before freezing was necessary to obtain the highest possible amount of extractable pigment from PSP. Microwave blanching for $3{\sim}4$ min or hot air blanching for $10{\sim}15$ min were effective in extracting pigment from PSP.

• Korean Journal of Food Science and Technology
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• v.34 no.2
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• pp.238-243
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• 2002

The effects of concentration and temperature on degradation of anthocyanins of purple-fleshed sweet potato pigment concentrate and a Japanese plum juice were determined over temperature ranges of 60 to $90^{\circ}C$ and 5 to $60^{\circ}C$, respectively. Degradation of anthocyanins in pigment concentrates followed the first-order reaction rate. Activation energies of the pigment solutions ranged 51.29-73.02 kJ/mol, linearly decreasing as concentration increased except the pigment solution of $8.4^{\circ}Brix$ which was not concentrated after extraction. Anthocynins in Japanese plum juice was also degraded by the first-order reaction kinetics with activation energy of 75.80 kJ/mol. Storage life of the beverage was extended with decreasing storage temperature. Pigment was ratained more than 80% until 8 months storage at $5^{\circ}C$.

• Proceedings of the Korea Contents Association Conference
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• 2013.05a
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• pp.361-362
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• 2013

As one of the steps toward understanding how the plant is well adapted to strongly saline habitats, the purple pigment compound that is accumulated in Suaeda japonica was extracted and characterized. The extracted pigment compound exhibited typical characteristics of betacyanin that were represented by water solubility, pH- and temperature-dependent color changes, sensitivity to light, UV-Vis spectra, and gel electrophoretic migration pattern. LC-MS of the extracted pigment compound showed the presence of two major protonated molecular ions ($[M+H]^+$) at m/z 651.1 and m/z 827.1. According to the DPPH assay, it was found to have an antioxidant activity that is linearly increased in proportion to the reaction time for up to 30 min, and the activity was comparable to that of control BHA at 9.0 mg/ml. The cytotoxic activity against several tumor cell lines was also examined following the MTT assay. The significant growth inhibitory effect was observed on two tumor cell lines, SW-156 (human kidney carcinoma) and HEC-1B (human endometrial adenocarcinoma). Probably, the pigment compound may function as an osmolyte to uphold halotolerant physiological processes in saline environment.