著者

Rie Kurata Yoshihiro Okada Takeo Sakaigaichi Yumi Kai Akira Kobayashi Keisuke Suematsu

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-103, (Released:2023-12-28)

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We investigated the anthocyanin composition of the purple sweet potato cultivar ‘Churakanasa’. The color tone of the paste was compared by L*, a*, and b* values and ‘Churakanasa’ exhibited a lower b* value, which indicates a bluish tint, than ‘Churakoibeni’, a popular cultivar for paste processing in Okinawa. High performance liquid chromatography (HPLC) analysis of the pigment extract showed that the anthocyanin composition of ‘Churakanasa’ was quite different from that of ‘Ayamurasaki’ and ‘Churakoibeni’. The analysis of the aglycone composition revealed that the cyanidin content (%) of ‘Ayamurasaki’ and ‘Churakoibeni’ contained 19.2% and 22.6% of cyanidins and 80.8% and 77.4% of peonidins, respectively. These findings indicate that these cultivars belong to the peonidin type. In contrast, ‘Churakanasa’ contained 86.4% cyanidin, indicating it to be a cyanidin-type cultivar. The steamed sweet potato paste made from ‘Churakanasa’ (cyanidin type cultivar) exhibited a bluer color compared to the peonidin-type cultivars. This observation suggests a direct correlation between the higher cyanidin content and the blue color intensity of the paste. HPLC-MS analysis of the two major HPLC peaks (peak I and II) of ‘Churakanasa’ suggested that the substance in peak I was YGM-0c; cyanidin-3-p-hydroxybenzoyl sophoroside-5-glucoside by mass, whereas peak II was YGM-1a; cyanidin-3-caffeoyl-p-hydroxybenzoyl sophoroside-5-glucoside. ‘Churakanasa’ exhibits unique color and pigment characteristics as it is the only purple sweet potato cultivar that has YGM-0c and -1a as its primary pigments.

著者

Toru Kobayashi Rie Kurata Yumi Kai

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.UTD-025, (Released:2019-02-01)

被引用文献数

9

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Despite increasing demand for sweet potato foliage, which is rich in functional components, efficient methods to maximize yield are still needed. In this study, cultivation tests for sweet potato (line Kyukei05303-3) were conducted over three consecutive years at a greenhouse to characterize seasonal changes in the foliage yield (leaves and stem-petioles), as well as the polyphenol content. The sweet potato foliage was harvested from May to November every week, and the average leaf yield was 855.3 g·m−2·year−1 on a dry weight (DW) basis. The yield and polyphenol content of the leaves were negatively correlated. The yield increased from spring to summer but decreased after mid-August. In contrast, the polyphenol content was highest in May, lower during the summer (June to August), and increased again after September. The average polyphenol content in the leaves was 6.9 g·100 g−1 DW and the total annual polyphenol yield was 59.0 g·m−2. The major component of polyphenols was caffeoylquinic acids. The seasonal changes in caffeoylquinic acids were highly correlated with the changes in total polyphenols. The polyphenol content was significantly correlated with air temperature, but not with sunshine duration, suggesting that air temperature is an important determinant of the polyphenol content during cultivation. These results provide a basis for the rapid cultivation of sweet potato for foliage production.