著者

木戸 めぐみ 三反田 詩織 倉田 理恵 寺原 典彦 吉元 誠 キド メグミ サンタンダ シオリ クラタ リエ テラハラ ノリヒコ ヨシモト マコト Megumi Kido Shiori Santanda Rie Kurata Norihiko Terahara Makoto Yoshimoto

出版者

鹿児島女子短期大学附属南九州地域科学研究所

雑誌

南九州地域科学研究所所報 (ISSN:09110275)

巻号頁・発行日

no.30, pp.7-12, 2014

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b-Amylase [EC 3.2.1.1] is an important enzyme for the industrial production of maltose as sweetener and as protective of starch degradation in food processing. Effects of polyphenolics, anthocyanin dyes and caffeic aid-derivatives prepared from sweetpotato on sweetpotato b-amylase were investigated for its industrial utilization. Crude extract of anthocyanin dyes did not inhibit b-amylase activity at a concentration of 2.0 mg/ml reaction mixture. In caffeoyl acid-derivatives, 3,4-dicaffeoyl-quinic acid had no inhibitory effect at a concentration of 2.0 mg/ml. Caffeic acid, chlorogenic acid, and 3,5-dicaffeoyl-quinic acid showed the inhibitory activity of about 20% against b-amylase at the same concentration.

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

Rie Kurata Toru Kobayashi

出版者

The Japanese Society for Horticultural Science

雑誌

The Horticulture Journal (ISSN:21890102)

巻号頁・発行日

pp.QH-044, (Released:2023-05-26)

被引用文献数

1

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Purple sweet potatoes are rich in the purple pigment anthocyanin. In recent years, it has been reported that the anthocyanin content of the same variety varies depending on the place of production. Therefore, to investigate the effect of soil temperature on the anthocyanin content of sweet potato tuberous roots, two types of covering materials, black and white mulch films, were used in the same field. The vines were planted in May, June and July; the cultivation period was set to 120–180 days and tuberous roots were harvested in September, October and November. The average soil temperature ranged from 22.9 to 26.5°C, with the white mulch having lower soil temperatures than the black mulch. The tuberous root yield increased with longer cultivation periods; the tuberous root yield in the May–November plot with a 180-day cultivation period was about twice that of the June–October and July–November plots with a 120-day cultivation period. The anthocyanin content of the tuberous root was negatively correlated with the average soil temperature; the test plots harvested in November had a higher anthocyanin content than the other test plots. In particular, the anthocyanin content of sweet potato cultivated in white mulch in July–November was about twice that cultivated in May–September. Although the factors that increase the tuberous root yield (prolonged cultivation period) are different from those that increase the anthocyanin content (lower temperature range), the tuberous root yield showed a larger effect on the total anthocyanin yield. Since the cultivation period needs to be prolonged to increase tuberous root yield, it would consequently increase the anthocyanin yield. The quality of the harvest was better under lower soil temperature as it led to an increase in the anthocyanin yield. Therefore, it was suggested that anthocyanin yields could be maximized by extending the growing season and harvesting at lower soil temperatures.

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.