Varietal differences in the yield and polyphenol content of sweet potato (Ipomoea batatas L.) foliage

摘要

We determined the foliage yield, polyphenol content, and polyphenol yield of weekly greenhouse-cultivated major varieties of sweet potato with the aim to utilize the foliage as a polyphenol source. The two-year study was conducted using five varieties from May to November 2012, Kokei No. 14, Koganesengan, Murasakimasari, Tamaakane, and Suioh, and three varieties from May to October 2014, Kokei No. 14, Koganesengan, and Beniharuka. The foliage yield of Koganesengan and Beniharuka in 2014 was significantly higher than other varieties. The foliage polyphenol content was significantly higher in Koganesengan in both years compared to others. The foliage polyphenol yield of Koganesengan and Beniharuka in 2014 was significantly higher than others. Koganesengan is a variety whose leaves represent a major portion of the total foliage; and the highest polyphenol content was in its leaves. Therefore, Koganesengan has the potential to be an efficient source of polyphenol. Our study provides basic data for the stable use of sweet potato foliage as a polyphenol-rich material.