Chusak, C.; Henry, C.J.; Chantarasinlapin, P.; Techasukthavorn, V.; Adisakwattana, S. Influence of Clitoria ternatea Flower Extract on the In Vitro Enzymatic Digestibility of Starch and Its Application in Bread. Foods 2018, 7, 102.
This study aimed to assess the effect of the Clitoria ternatea L. flower extract (CTE), on the inhibition of pancreatic α-amylase, in vitro starch hydrolysis, and predicted the glycemic index of different type of flours including potato, cassava, rice, corn, wheat, and glutinous rice flour. The application in a bakery product prepared from flour and CTE was also determined. The results demonstrated that the 1% and 2% (w/v) CTE inhibited the pancreatic α-amylase activity by using all flours as a substrate. Moreover, 0.5%, 1%, and 2% (w/v) CTE showed a significant reduction in the glucose release, hydrolysis index (HI), and predicted glycemic index (pGI) of flour. In glutinous rice flour, 1% and 2% (w/v) CTE had a significantly lower level of rapidly digestible starch (RDS) and slowly digestible starch (SDS) with a concomitant higher level of undigested starch. The statistical analysis demonstrated strong positive significant correlations between the percentage of CTE and the undigested starch of wheat and cassava. The addition of 5%, 10%, and 20% (w/w) CTE significantly reduced the rate of starch digestion of the wheat bread. The pGI of bread incorporated with 5% CTE (w/w) was significantly lower than that of the control bread. Our findings suggest that CTE could reduce the starch digestibility, the HI, and pGI of flour through the inhibition of carbohydrate digestive enzymes. Taken together, CTE may be a potent ingredient for the reduced glycemic index of flours.
We would like to thank the 100th Anniversary Chulalongkorn University Fund for the Doctoral Scholarship, Overseas Research Experience Scholarship for Graduate Student, and the 90th Anniversary Chulalongkorn University Fund (Ratchadaphiseksomphot Endowment Fund), Graduate school, Chulalongkorn University. This research was supported by the Grant for International Research Integration: Chula Research Scholar, and the Grant for Join Funding, Ratchadaphiseksomphot Endowment Fund, Chulalongkorn University. The author gratefully acknowledges Lalana Thiranusornkij and Parichart Thamnarathip from KCG Excellence Center, KCG Corporation Co., Ltd. for providing bread preparation.