Optimal Extraction Condition of Anthocyanins in Soybean (Glycine max) with Black Seed Coats

Soybeans (Glycine max) with a black seed coat have been widely utilized as food source and as a medicinal herbs in Korea. The pigmentation in the seed coat of black soybean is due to accumulate anthocyanins in the epidermis palisade layer. The anthocyanin content and composition of the black soybean seed coat are considered as a standard. of quality evaluation of black soybean. The main objective of this study was to investigate the optimal condition for an extraction method of anthocyanins and compare anthocyanin quantity and composition within black soybean varieties and germplasms. In the test of extraction solvent, absorbance at 530 nm and Hunter's a value were increased as increasing the concentration of MeOH, but Hunter's Land b values were the exact opposite of absorbance and Hunter's a values. There was no significant difference for anthocyanin contents from 1% HCl - $H_2O$ to 1% HCl - 80% MeOH. In the aspects of anthocyanin contents and HPLC peak resolution, 1% HCl - 20% MeOH extraction solution was the most suitable solvent. Among the 5 kinds of extraction method using 1% HCl - 20% MeOH solution, the anthocyanin contents of room temperature extraction at 72 h was the highest among the methods. High extraction temperature, sonication and reflux method influenced on the decrease of anthocyanin contents because of breakdown of anthocyanins. There was no significant difference for extraction time between 12 h and 24 h. However, the optimal extraction condition were at room temperature for 12 h. The anthocyanin contents in seed coats of black soybean were determined on the basis of HPLC peak area at 530 nm. Ten black soybean varieties and germplasms were tested with optimal conditions founded in this study. On the basis of antocyanin component, these can be classified into three groups; C3G, C3G + D3G and C3G + D3G + Pt3G. The total anthocyanin content in seed coats ranged from 1.58 to 10.62 mg/g of seed. The total anthocyanin content of the variety "Geomjeongol" was about 7 times higher than that of variety "Heugchong". Information for extraction method and diversity in antocyanin of soybean seed coats can be used for future research for germplasm evaluation and development of high quality black soybean varieties.

검정콩 종피 함유 안토시아닌의 최적 추출조건

검정콩 품질평가의 한 기준이 되는 안토시아닌의 함량평가를 위한 분석기술 개발의 일환으로 검정콩 종피 함유 안토시아닌의 최적의 추출용매 및 추출방법을 확립하고, 주요재배 검정콩 종피 함유 안토시아닌의 함량을 정량적으로 평가한 결과를 요약하면 다음과 같다. 1. 검정콩 종피 함유 안토시아닌의 최적 추출용매를 검토한 결과 1% HCl - $H_2O$로부터 1% HCl - 80% MeOH용액까지 통계적 차이가 인정되지 않았으나, 산술적으로 1% HCl - 60% MeOH 용액으로 추출하였을 때 총 안토시아닌의 함량이 7.72 mg/g으로 가장 높은 양상을 나타내었으나, 추출용매에 메탄을 함량이 높아질수록 안토시아닌 피크의 분리도가 극히 불량한 결과를 나타내므로 종합적 견지에서 볼 때 1% HCl - 20% MeOH를 이용하여 안토시아닌을 추출하는 것이 가장 우수한 것으로 평가되었다. 2. 검정콩 종피 함유 안토시아닌의 최적 추출방법 및 추출시간을 검토한 결과 상온 12시간 추출이 가장 우수한 결과를 나타내었으며, 추출시간이 24시간 이상 지속될 경우 추출시간이 증대됨에 따라 안토시아닌의 함량이 소량 감소되는 양상을 확인할 수 있었다. 3. 국내외 주요 재배 검정콩 품종별 종피 함유 안토시아닌 색소의 함량을 비교한 결과 총 안토시아닌의 함량 범위는 1.58-10.62 mg/g으로 조사되었고, 조사된 품종 중 검정 올콩이 10.62 mg으로 가장 높은 양상을 나타내었으며, 가장 낮은 함량을 나타낸 흑청콩 대비 약 7배 높은 안토시아닌 함량을 나타내었다.