Quality Characteristics of Kimchi Prepared with Dioscorea batatas

In this study, we produced kimchi with cooked Dioscorea batatas yam based on the its outstanding nutritional value, biological activity, and pharmacological action. Sliced kimchi cabbage, processed white radish kimchi (kkakdugi), and whole kimchi cabbage were prepared with 3% Dioscorea batatas, and the physicochemical and bioactivity characteristics were analyzed. In three kinds of Dioscorea batatas. The pH of the kimchi decreased and its acidity increased as the storage period was extended. The period of the maximum total viable cell count of the sliced cabbage and the processed white radish kimchi (kkakdugi) was 14 days, while the period for whole kimchi cabbage was 21 days. The period of maximum lactic acid bacteria count was 14 days for all three kinds. For physiological activities, polyphenol and flavonoid contents and DPPH elimination were highest immediately after production of the kimchi. Also, anthocyanin content increased as the storage period extended. The pH, acidity, total viable cell count, lactic acid bacteria count, and physiological activities were shown to be different according to the type of kimchi and the storage period.

Quantitative Analysis of Bioactive Phenanthrenes in Dioscorea batatas Decne Peel, a Discarded Biomass from Postharvest Processing

Dioscorea batatas Decne (Chinese yam) has been widely cultivated in East Asia for the purposes of food and medicinal uses for centuries. Along with its high nutritional value, the medicinal value of D. batatas has been extensively investigated in association with phytochemicals such as allantoin, flavonoids, saponins and phenanthrenes. Phenanthrenes are especially considered the standard marker chemicals of the Chinese yam for their potent bioactivity and availability of analysis with conventional high performance liquid chromatography with ultraviolet detection (HPLC-UV) methods. In order to investigate how much the contents of phenanthrenes are in the actual food products provided for consumers, D. batatas tuber was peeled and separated into its peel and flesh as in the conventional processing method. A quantitative analysis using the HPLC-UV method revealed that phenanthrenes are concentrically present in the D. batatas peel, while phenanthrenes are present in the flesh under the limit of detection. The difference in the contents of phenanthrenes is estimated to have arisen the considerable difference of antioxidant potential between the peel and the flesh. The results from this study suggest the high value of the discarded biomass of the Chinese yam peel and the necessity for the utilization of the Chinese yam peel.