Radical scavengers in sweet potato . . .
Table 2—Area percentages of anthocyanins in F-II
a
peak area (%)
YGM-1
YGM-2
YGM-3
YGM-4b
YGM-5a
YGM-5b
YGM-6
Other
Ayamurasaki
Kyushu-132
Miyanou-36
Bise
1.9
9.6
24.3
34.8
42.9
2.0
2.4
35.5
16.2
20.4
5.7
3.2
15.1
35.1
12.5
17.7
10.3
2.6
0.9
2.0
9.0
15.4
8.8
1.1
2.9
20.4
32.5
2.1
1.1
2.6
21.3
17.5
2.9
2.0
2.7
13.0
9.0
8.7
8.8
14.0
Tanegashimamurasaki
a
Mean values of 5 tubers
cept anthocyanins for “Miyanou-36” and “Bise,” while they were the sum total of activity by each component. Judging from the
anthocyanins for “Ayamurasaki” and “Kyushu-132.” This evi- content and ratio of each component, the most active contribu-
dence strongly supports the fact that both anthocyanins and tors to scavenging DPPH radicals were phenolic compounds
polyphenols play an important role in the radical-scavenging ac- such as ChA and iso-ChA in “Miyanou-36” and “Bise” and antho-
tivity of purple-fleshed sweet potatoes. The summation of both cyanins with peonidin aglycon in “Ayamurasaki” and “Kyushu-
activities brings by their components expressed as total activity. 132.”
Thus, attention should be given to the existence of anthocyanins
and polyphenols when estimating the radical-scavenging activi-
ty of purple-fleshed sweet potatoes.
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MS 20010540 Submitted 9/30/01, Accepted 3/11/02, Received 3/13/02
We are indebted to the Laboratory of Sweet Potato Breeding, National Agricultural Re-
search Center for Kyushu Okinawa Region, for donating the sweet potato cultivars
“Ayamurasaki,” “Kyushu-132,” and “Tanegashimamurasaki.” In addition, we thank Messrs.
H. Hayase, M. Fukumori, and M. Kato for their technical assistance. This study was sup-
ported by a Grant-in Aid from the Research Program provided by the Ministry of Agricul-
ture, Forestry and Fisheries (MAFF) of Japan and the Cooperative System for Supporting
Priority Research performed by the Japan Science and Technology Corp (JST).
Authors Oki, Masuda, Furuta, Nishiba, and Suda are with National Agri-
cultural Research Center for Kyushu Okinawa Region, National Agricul-
tural Research Organization, 2421 Suya, Nishigoshi, Kikuchi, Kumamoto
861-1192, Japan. Author Terahara is with Dept. of Food Science and Tech-
nology, College of Horticulture, Minami-Kyushu Univ., Hibarigaoka,
Takanabe, Miyazaki 884-0003, Japan. Direct inquiries to author Suda (E-
mail: ikuosu@affrc.go.jp).
Conclusion
T WAS FOUND THAT ANTHOCYANINS AND PHENOLIC COMPOUNDS
I
were potent radical scavengers in purple-fleshed sweet potato
cultivars. There are cultivar differences in the total radical-scav-
enging activity irrespective of the shade of purple, resulting from
1756 JOURNAL OF FOOD SCIENCE—Vol. 67, Nr. 5, 2002