Abstract:

Purpose: To evaluate the antioxidant activity and in vitro starch digestibility of cooked noodles made from two
tartary buckwheat cultivars (Xinong 9940 and 9909) and three common buckwheat cultivars (Dianbian red flower, Yuqiao
4 and Wensha) by comparison with wheat noodles. Method: Total flavonoids content was measured by NaNO2-Al(NO3)3
assay, and DPPH free radical scavenging capacity assay and reducing power method were employed to evaluate the
antioxidant capacity of the noodle samples. The content of resistant starch was measured through enzymolysis. Additionally,
total starch hydrolysis was tested at different times, and data were plotted as starch hydrolysis degree vs. time curves. Estimated
glycemic index (EGI) was calculated according to the curves. Results: The antioxidant property of buckwheat noodles was
significantly superior to wheat noodles. Moreover, the content of total flavonoids ranged from 600.76 to 183.33 mg /100 g and
tartary buckwheat noodles had higher total flavonoids content and antioxidant capacity and the best cultivar was Xinong
9909. Resistant starch content ranged between 2.78% and 6.07%, depending on the cultivar. Furthermore, EGI of buckwheat
noodles were significantly lower than that of wheat noodles, and different among cultivars. EGI of Dingbian red flower,
Wensha, Xinong 9909 and Xinong 9940 was less than 75, thus belonging to middle-EGI food. Conclusion: The quality of
buckwheat noodles is generally better than that wheat noodle and differs among cultivars and among the tested cultivars,
Xinong 9940 processes the best overall quality. As a result, buckwheat noodles can be served as daily food with the
preventing function against chronic disease such as diabetes.

Key words: buckwheat, noodle, flavonoids, antioxidant capacity, estimated glycemic index, resistant starch