Effect of replacing wheat flour with coconut flour to carrot cake on in vitrostarch digestion rate and sensory evaluation

Abstract

Thai coconut flour obtains from by-product of the coconut milk industry were utilized as a source of dietary fiber in carrot cake and its effect on starch digestibility and sensory evaluation of modified carrot cakes were evaluated. Replacement rate of coconut flour (CF) were 20, 30 and 40% w/w from a control recipe. In vitro starch digestion was studied using the Englyst’s method (Englyst et al., 2000) with modification. The glucose released values were recorded at time 0, 20, 60 and 120 min of digestion and converted to available glucose released. Results showed that mean values of released glucose from all levels of replacement at every time point except zero time were significantly less than the control. However, 40%CF replacement had significantly lowest released glucose and also increment area under the curve of released glucose of 120 min (IAUC). There were significantly negative correlations between G20 (released glucose at 20 min), G60, G120 and IAUC with levels of dietary fiber contents. The sensory evaluation was assessed by 31 panelists (19 females, 12 males) with type 2 diabetes at Ramathibodi hospital. It was done for seven attributes like appearance, color, flavor, taste, softness, texture and overall liking using a 9-point hedonic scale. Median values of sensory scores of all the attributes were between 7 and 8 meaning that the modified carrot cakes were evaluated as liked moderately to like very much, and there were no significant differences in the all attributes among the three levels of CF studied. Hence up to 40% of wheat flour can be replaced by coconut flour to produce carrot cake with acceptable sensory quality. Replacing wheat flour with Thai coconut flour in carrot cake, may potentially reduce the glycemic index of the cake to benefit diabetic, as well as non-diabetic individuals.