• Journal of Applied Biological Chemistry
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• 제49권3호
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• pp.75-81
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• 2006

A full-length cDNA encoding dihydroflavonol 4-reductase (st-dfr) of potato was isolated by rapid amplification of cDNA ends, and their expression was investigated from purple-fleshed potato (Solanum tuberosum L. cv. Jashim). The st-dfr exists as a member of a small gene family and its transcripts was abundant in the order of tuber flesh, stem, leaf, and root. The expressions of st-dfr gene were light inducible and cultivar dependant. Transgenic potato plants harboring antisense st-dfr (AS-DFR) sequences were analyzed. The accumulation of mRNA was nearly completely inhibited as a result of introducing an AS-DFR gene under the control of the 35S CaMV promoter into the red tuber skin Solanum tuberosum L. cv. Desiree. The anthocyanin content of the tuber peels of the transgenic lines was dramatically decreased by up to 70%. The possible production of flavonols in the peels of AS-DFR transgenic potatoes was discussed.

• 한국식품영양학회지
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• 제23권1호
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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.

• 한국식품영양과학회지
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• 제39권10호
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• pp.1476-1480
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• 2010

육질색에 따른 일반고구마, 주황색고구마 및 자색고구마로부터 갈변방지제 처리와 건조방법을 달리하여 분말을 제조한 후 고구마 분말의 이화학적 특성을 분석하였다. 고구마 분말의 조단백질, 회분 및 식이섬유 함량은 자색고구마에서 가장 높았고 조지방과 전분 함량은 주황색고구마에서 가장 높게 나타났다. 고구마 분말의 평균 입자크기는 주황색고구마 분말에서 가장 크게 나타났으며 각각의 고구마 분말에서 둥근형 또는 다각형의 전분입자 형태를 관찰할 수 있었다. 고구마 분말의 수분흡수지수 및 oil 흡수율은 열풍건조방법으로 제조한 분말이 동결건조에 의한 분말보다 높은 경향을 주었다. 고구마 분말의 수분용해도지수는 일반고구마와 자색고구마의 경우 건조조건에 따른 차이가 크지 않은 반면, 주황색고구마의 경우 열풍건조 한 분말에서 수분용해도지수가 높게 나타났다.

• 한국식품조리과학회지
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• 제32권6호
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• pp.677-685
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• 2016

목적: 본 연구에서는 탈수방법 중 분자압축탈수법을 이용하여 탈수한 자색고구마로 제조한 타르트의 저장 중 품질특성을 조사하였다. 연구방법: 자색고구마타르트의 수분함량, 수분활성도, 총페놀함량, 안토시아닌함량, DPPH 자유라디칼 소거능, 색도 및 관능평가를 45일 동안 실시하였다. 결과: 탈수제인 말토덱스트린 20%, 40%, 60%, 80%로 분자압축탈수 후 제조한 자색고구마타르트 크러스트의 수분함량은 45일 저장 후 8.47%, 7.95%, 6.96%, 6.24%로 분자압축탈수하지 않은 자색고구마로 제조한 타르트 크러스트의 수분함량인 11.99%에 비하여 낮았다 (p<0.05). 하지만 총페놀함량, 안토시아닌 함량과 DPPH 자유라디칼 소거능이 분자압축탈수한 자색고구마타르트가 그렇지 않은 타르트에 비해 낮게 나타났다(p<0.05). 결론: 분자압축탈수 후 제조한 자색고구마타르트는 수분함량을 효율적으로 낮춰주어 저장 동안 타르트 크러스트의 바삭함을 유지할 수 있었으나 총페놀 및 안토시아닌 함량, DPPH 자유라디칼 소거능, 색도 및 관능평가 결과가 감소하였다.

• 한국식품과학회지
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• 제31권4호
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• pp.1090-1095
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• 1999

자색, 황색의 유색고구마와 미황색 및 일반고구마의 알코올 추출물의 항산화성과 항미생물활성을 조사하였다. 고구마의 항산화성은 자색고구마와 황색고구마가 가장 높았으며, 다음으로 미황색고구마인 생미, 연미, 그리고 일반 품종의 고구마인 황미가 높게 나타났다. 외관적인 곰팡이의 발생율과 표면세균 및 곰팡이의 수는 유색고구마인 자색고구마와 황색고구마가 미황색고구마나 일반고구마에 비해 뚜렷하게 낮았다. 사용한 모든 고구마가 효모와 곰팡이에는 항균활성을 나타내지 않았으나, Streptococcus faecalis에 대해서는 현저한 생육억제효과가 나타났으며, 특히 유색고구마는 일반적인 박테리아에 대해 항균성을 나타냈다.

• 한국식품과학회지
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• 제27권5호
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• pp.819-825
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• 1995

고안토시아닌을 함유한 자색고구마의 식량자원으로서의 활용도를 높히고자 엷은 황색고구마와 동시에 영양성분을 분석하였다. 자색고구마의 일반성분 중 단백질 함량이 2.01%, 무질소물이 25.73%였으며, 조지방이 0.25%로 엷은 황색 고구마보다 높았다. 총아미노산의 구성은 2품종 모두 aspartic acid, serine, alanine 및 valine이 주성분이었으며, 자색고구마일 경우 함유황 아미노산이 제1제한 아미노산이었다. 지방산의 조성은 2품종 모두 palmitic acid, linoleic acid가 80% 이상으로 주종을 이루었으며, 불포화지방산 함량이 포화지방산 함량보다 더 높았다. 2품종의 고구마 모두 탄수화물 함량은 75%이상이었고 자색고구마의 중성당 함량은 67.22%로 이중 대부분은 glucose였다. 그리고 uronic acid는 11.88%, starch 59.42%였으며, 특히 자색고구마의 유리당은 엷은 황색고구마의 1/3 정도로서 고구마 고유의 단맛이 적었다. 비타민 $B_1$, 비타민 $B_2$ niacin 함량은 2품종 모두 큰 차이는 없었으나 비타민 C의 함량은 자색고구마가 63.4mg%, 엷은 황색고구마가 48.7mg%였다. 다음 무기질 구성원소로는 자색고구마일 경우 K, Mg, Ca, Na 등이 주성분이었고, 그외 Fe, Mn, Zn, Cu, Al 등이 확인되었다. 총식이섬유는 자색고구마가 13.43%로서, 이중 수용성식이섬유가 7.74%, 불용성식이섬유는 5.69%였으며 또 엷은 황색 고구마는 총식이섬유 함량이 9.79%로 수용성, 불용성 식이섬유 함량이 비슷하였다.

• 한국식품과학회지
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• 제34권2호
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• pp.346-349
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• 2002

자색고구마에서 anthocyanin 색소를 추출한 후 EDTA, gallic acid, phosphoric acid, propyl gallate 및 sodium ascorbate 등을 첨가하여 $20^{\circ}C$에서 20,000 lux의 백색광을 조사하면서 색소의 광에 대한 안정성을 살펴보았다. EDTA와 sodium ascorbate가 자색고구마 색소의 광안정성을 증진시켰으며, 이들은 각각 100 ppm, 1,000 ppm 이상 사용하였을 때 효과가 높게 나타났다.

• Food Science and Biotechnology
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• 제18권6호
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• pp.1487-1494
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• 2009

The effects of drying temperature (55, 60, and $65^{\circ}C$) and addition levels of maltodextrin (MD) (10, 20, and 30%) on the physicochemical properties and nutritional quality of purple sweet potato flour were investigated. MD-added flours had higher $L^*$ values, water soluble index, total phenolic, and anthocyanin contents than untreated flour. However, $a^*$, $b^*$ values, water absorption index, and swelling capacity were dependent on the drying temperature and MD concentration. On the other hand, untreated flour had a higher ascorbic acid content compared to the MD-treated flour. Ascorbic acid contents decreased, whereas anthocyanin content was not significantly different, with increasing drying temperatures. MD was positively correlated with phenolic content, anthocyanin, hue angle, and water soluble index. However, there was no correlation between quality parameters and glass transition temperature. The best quality product was obtained when samples were pretreated with MD before drying, regardless of drying temperature.

• 한국육종학회지
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• 제41권4호
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• pp.385-390
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• 2009

A resveratrol synthase (RS) gene was isolated from peanut (Arachis hypogaea, L. cv. Jinpoong) plants. This gene was placed under the control of the cauliflower mosaic virus 35S promoter (CaMV35S) and introduced into two Korean varieties of potato (Solanum tuberosum L. cvs. Jasim and Jowon) plants by Agrobacterium-mediated gene transfer. Putative transformants were screened by PCR with primers designed from CaMV 35S promoter, NOS terminator and RS gene. Most of selected transgenic potato plants showed the amplification of expected fragments by PCR of genomic DNA with gene-specific primers, while they were absent in untransformed control plants. Expression of the resveratrol synthase gene was also examined by northern blot analysis. The transformants showed a band which was lacking in the control plant, confirming that the introduced gene is transcribed into mRNA in the transformants. The strength of the band, which reflected the level of mRNA expression, differed among the individual transformants. Among the transformants obtained, the highest trans-resveratrol content in the transgenic young leaves of purple-fleshed "Jashim" was $2.11{\mu}gg^{-1}$ fresh weight and that in the microtubers in vitro of purple fleshed "Jashim" was $8.31{\mu}gg^{-1}$ fresh weight. This amount of resveratrol may have a positive biological effect on human health.

• Natural Product Sciences
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• 제15권3호
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• pp.134-138
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• 2009

In an attempt to establish anti-ulcerogenic activity of potato tubers, inhibitory activity against ethanol- and indomethacin-induced gastric ulcer models in rats was evaluated for the first time. From several varieties of potato tubers including Solanum tuberosum L. cv. Superior (white skin and fresh potato) and two new varieties of (Bora valley and Gogu valley), raw potato juice was prepared and the starch was obtained from each juice by filtration and drying. Upon oral administration to rats, raw potato juice showed more or less inhibitory activity. The starch showed higher and dose-dependent inhibitory activity, suggesting that the active ingredient in raw potato juice may be the starch. Particularly, the starch obtained from the tubers of new potato variety, "Bora valley," with purple color, showed the highest inhibitory activity (62.4% and 37.1% inhibition of ulcer index at 500 mg/kg), while omeprazole (proton pump inhibitor) used as a reference drug showed 74.4% and 75.7% inhibition at 20 mg/kg against ethanol- and indomethacin-induced ulcer formation, respectively. The present study provides a first evidence of anti-ulcerogenicity of raw potato juice and the starch. Especially, the starch from "Bora valley" strongly inhibited ulcer formation in rats. Considering that these are food components, they may be safely used for anti-ulcerogenic nutraceuticals.