Abstract: Water pretreatment followed by dichloromethane extraction was used to extract radish seed oil. One-factor-at-a-time experiments and subsequence response surface analysis were conducted to optimize temperature, extraction time and material/liquid ratio based on oil yield. The optimal extraction conditions were found to be material/liquid ratio of 1:21.8, extraction duration of 1.76 h and extraction temperature of 27.3 ℃. Under these conditions, the yield of radish seed oil was 35.58% and the extraction recovery was calculated as 95.38% relative to 37.30% of the crude fat content in radish seeds as determined by Soxhlet extraction. In addition, many kinds of fatty acids were detected in radish seed oil, including mustard acid, oleic acid, linoleic acid, eicosadienoic acid and linolenic acid. Unsaturated fatty acids accounted for 88% of the total fatty acids and the content of sulforaphene in radish seed oil was 89.5 mg/kg.

Key words: radish seed oil, response surface methodology, extraction process