Effects of storage condition on the bioactive compound contents of Korean cabbage

The influence of common storage condition (i.e., temperature and period) on the phytochemical contents of Korean cabbage was investigated. The total polyphenol and flavonoid contents of fresh Korean cabbage extract were 308.48 μg gallic acid equivalent/g d.w. and 5.33 μg quercetin equivalent/g d.w., respectively. Seven glucosinolate peaks were detected in Korean cabbage representing progoitrin, glucoalyssin, gluconapin, glucobrassicanapin, glucobrassicin, 4-methoxyglucobrassicin, and neoglucobrassicin based on HPLC and LC-MS analysis. The concentration of total glucosinolates in fresh Korean cabbage was 13.55 μmol/g d.w. Our results suggest that the total glucosinolate content in Korean cabbage did not much change more over 7 days of storage at 4°C but a little bit decreased in stored at ambient temperature. The extractable β-carotene, lutein as well as tocopherol contents in Korean cabbage were decreased by increasing storage period at both temperatures of 4°C and ambient temperature. Longer storage period at ambient temperature may reduce the levels of health promoting compounds. Based on our results refrigeration at 4°C can help preserve the nutritive value of Korean cabbage by maintaining high levels of glucosinolates and other bioactive compounds.