Formular Screening of Buckwheat Mixed Rice Rich in D-fagomine and Its Effect on Glycemic Index
DING Hui;PENG Qing;QIAO Yu;ZHAO Shi-feng;CHEN Xu;LI Yang;WANG Kai-qiang;ZHANG Yu-wei;SHI Bo;Feed Research Institute, Chinese Academy of Agricultural Sciences/Key Laboratory of Feed Biotechnology of Ministry of Agriculture;Zhangjiakou Academy of Agricultural Sciences;College of Food Science,Shenyang Agricultural University;
A kind of buckwheat mixed rice with a good cooked taste and health-promoting functions was prepared with rice and buckwheat containing D-fagomine for providing people with an alternative choice of staple food, beneficial for reducing the glycemic index. A quantitative method to measure D-fagomine from 23 different origin buckwheat varieties was established by using ultra high-performance liquid chromatography coupled to tandem mass spectrometry(UPLC-MS/MS), and a kind of buckwheat with the highest concentration of D-fagomine was selected for cooking buckwheat mixed rice from the above buckwheat varieties. The content of main nutrient components, flavonoids and D-fagomine in this buckwheat were assayed and compared. The optimal cooking parameters were determined by using factorial design and sensory evaluation methods to evaluate the influence of addition ratio of buckwheat and water on the quality of cooked rice mixed with buckwheat. The postprandial hypoglycemic effect of this cooked rice mixture was investigated through the determination and comparison of digestion propertiesin vitro, glycemic index measured in vitro and in vivo and blood glucose change curves in rat. The results of experiment showed that Bendidali buckwheat, a kind of sweet buckwheat, had the highest concentration of D-fagomine(19.57 mg·g~(-1)) among the 23 buckwheat varieties and was used to process the buckwheat mixed rice. Bendidali was rich in nutrition. According to the results of sensory evaluation, three suitable methods of cooking buckwheat mixed rice were screened. The cooked rice mixture with 24%(w/w, the ratio of buckwheat in the mixture) had the best taste among the three ratios of 8%, 24% and 48%(w/w). With the increasing of the amount of buckwheat, the glycemic index of the cooked rice mixture decreased. Compared with other two kinds of cooked rice mixed with common sweet buckwheat, the cooked rice added Bendidali buckwheat could decrease the glycemic index of rat in vivo in a dose-dependent manner. This postprandial hypoglycemic effect in vivo of rat should be attributed to the action of D-fagomine in buckwheat mixed rice. Compared with commercial common buckwheat, the Bendidali buckwheat had good postprandial hypoglycemic effect and was particularly suitable for processing cooked buckwheat mixed rice.