고당옥은 2011년에 농촌진흥청 국립식량과학원에서 개발한 단교잡종 단옥수수로 이삭의 색깔은 노란색이며 자식계통KSE5를 종자친으로 하고 KSE19를 화분친으로 한다. 고당옥의 출사일수는 표준품종(단옥3호)보다 3일 정도 늦었고 고당옥의 이삭길이는 17.6 cm, 이삭직경은 4.4 cm였으며 착립장률은 87.1%로 표준품종과 유사하였다. 그러나 당도는 24.3 °Bx로 표준품종 14.1 °Bx보다 높았고 내도복성도 표준품종보다 우수하였다. 2009년부터 2011년까지 지역적응시험에서 고당옥의 단위면적당 이삭수와 이삭중은 표준품종과 유사하였으며 채종시험결과 종자친과 화분친간 개화기가 잘 일치하였다.

Even though plum is well known as a health food, the available processed food of it is quite limited. Furthermore it is difficult to find an easy processing method for leading to a value added product at farmhouse. This study was investigated to effects of temperature for plum extract juice by osmosis of yellow sugar. The plum was mixed with yellow sugar at equal ratio(w/w) to obtain yellowish extracted plum juice and then located in incubator at 15, 25, 35, respectively. The sugar content of extract was high at the early period but decreased throughout extraction period and it was about 66.1~67.4Brix. The color difference was increased yellowish throughout the extract period. The pH of it was decreased throughout extract processing but citric acid content was increased. The speed of extraction during extraction processing was more rapid at 15 than 3. However sensory evaluation score of taste and flavour was obtained at 15 than 3, so the prefer temperature for plum extract juice by osmosis of yellowish sugar was 15~2