Abstract
Soybean sprouts have good digestibility, high isoflavone content compared with soybean seeds, and large amounts of aspartic acid, which is effective in eliminating hangovers. However, the region between the cotyledon and hypocotyl in soybean sprouts appears purple, the product value of soybean sprouts reduces. To date, the scientific correlation among factors such as growth temperature, spray water temperature, and cultivation periods for soybean varieties related to purple color expression between the cotyledon and hypocotyl of soybean sprouts are unknown. The purpose of this study was to identify the factors regulating the expression of purple color between the cotyledon and hypocotyl of soybean sprouts. Of 15 Korean soybean varieties with purple color in the hypocotyls and flowers, 9 varieties, including Sowonkong, Wonhwang, Sinhwa, Eunhakong, Pungsannamulkong, Paldonamulkong, Kwangankong, Shingang, and Jangki showed purple color between the cotyledon and hypocotyl of sprouts. However, the remaining six cultivars, including Dachae, Myeongjunamulkong, Sobaeknamulkong, Sojinnamulkong, Anpyeong, and Jonam, did not show purple color. The proportion of soybean sprouts with purple hypocotyls was the lowest at $26^{\circ}C$ and there was no significant difference at the other three cultivation temperature conditions ($17^{\circ}C$, $20^{\circ}C$, and $23^{\circ}C$). Similar to the results of the cultivation temperature experiment at five different spray water temperatures ($10^{\circ}C$, $17^{\circ}C$, $20^{\circ}C$, $23^{\circ}C$, and $26^{\circ}C$), the proportion of soybean sprouts with purple hypocotyls was the highest at the lowest spray water temperature ($10^{\circ}C$), and lowest at the highest temperature. Additionally, there was no purple color expression in soybean sprout hypocotyls on the $3^{rd}$ day after soybean sprouting. However, the highest expression level was observed on the $4^{th}$ day. Then, on the $5^{th}$ day, the proportion of soybean sprouts with purple hypocotyls reduced significantly, compared with that on the $4^{th}$ day. The results showed that interaction among these factors under cultivation conditions was remarkably effective for the expression of purple color in hypocotyls under the dark condition. These results suggested that cultivation temperature and spray water temperature for purple color expression in soybean sprout hypocotyls are the most important factors in the sprout cultivation environment.
국내에서 육성된 자색배축을 나타내는 품종들의 콩나물 재배시 자색 발현을 조사하고 자색의 배축발현에 관련된 재배요인을 구명하여 자색배축 콩나물 품종을 콩나물 원료콩으로 확대하는데 필요한 기초자료를 제공하고자 시험을 실시하였다. 이에 배축색과 꽃색이 모두 자색인 콩나물 콩 15품종을 콩나물 재배기에서 재배하면서 콩나물 배축의 자색발현 정도를 조사하였다. 그 결과, 다채, 명주나물콩, 소백나물콩, 소진나물콩, 안평 및 조남 등 6품종은 자색이 발현이 되지 않았으나, 소원콩, 원황, 신화, 은하콩, 풍산나물콩, 팔도나물콩, 광안, 신강 및 장기 등 9품종은 자색이 발현되었다. 재배온도, 재배기간, 관수온도가 자색발현에 고도로 유의한 요인으로 작용하였고, 이들 간의 상호작용 효과도 통계적으로 고도로 유의한 것으로 나타났다. 또한, 콩나물 배축의 자색발현은 콩나물 재배환경에 영향을 받는 것으로 조사되었다. 재배온도에 따른 자색발현 개체비율은 재배온도 $17^{\circ}C$, $20^{\circ}C$, $23^{\circ}C$에서 32.4~34.2%의 비율을 보인 반면 $26^{\circ}C$에서는 17.2% 만이 자색을 나타내어, 재배온도가 제일 높은 시험구에서 자색발현이 가장 낮게 나타났다. 관수온도에 따른 자색발현 개체비율은 관수온도가 제일 낮은 $10^{\circ}C$에서 36%로 가장 많은 개체비율을 보였다. 그리고 관수온도가 높아질수록 자색발현 개체비율이 점차 감소하여 가장 높은 온도인 $26^{\circ}C$에서 가장 낮은 개체비율을 나타내었다. 재배기간에 따른 자색발현 정도는 재배 3일째에는 자색발현이 전혀 없었으나 4일째에 52%로 가장 높은 발현비율을 보였고 5일째에는 감소하여 36%의 개체가 자색배축을 나타내었다.
