Tartary buckwheat has established itself as a functional food source because of its basic nutrition and phenolic compound contents, such as dietary fiber (DF) and rutin (RU). However, little information has been obtained concerning the comparative effects of DF and RU on the in vitro and in vivo glucose responses of tartary buckwheat flour. Moreover, the relationship between the flour’s in vitro starch digestibility and its components’ blood glucose response is not well-known. This study found that DF and RU reduced rapidly digestible starch (RDS) by 37.32→33.88% and 41.71→30.28%, whereas they increased resistant starch (RS) by 30.47→31.46% and 28.41→36.78%, respectively. Furthermore, RU had a lower glycemic index (GI) compared to DF. The regression equation for the in vitro and in vivo data from RU exhibited positive correlation (R 2 = 0.99); however, DF did not display positive correlation, which indicates that the in vitro and in vivo GI mechanisms by DF and RU are different.

Evaluation of the antioxidant activity of the bakery products is important in order to establish healthy consumption patterns. Aronia and blackberry extract at different levels (0%, 5%, 10%, 15%, and 20%) were used to investigate their comparative effects on the physical properties and antioxidant capacity of cookies. The final cookies were evaluated for physicochemical and sensory properties as well as total phenol content, DPPH radical scavenging activity, and FRAP assay. Substitution of aronia and blackberry extracts significantly (p<0.05) increased the moisture content and spread ratio compared to the control that did not contain the extract. However, types of the extract (aronia or blackberry) did not significantly affects the moisture and spread ratio of cookies at the same concentrations (p>0.05). The lightness and yellowness values of cookies were decreased while the redness value was increased by the amount of the extract compared to control (p<0.05). For textural properties, the hardness and chewiness of cookies were increased by the concentration of extract, and highest at 20% of both extracts. Polyphenol content in the cookies was increased with the concentration of the extract added into the cookies. Consistently, the antioxidant activity was significantly increased as the concentration of the extract was increased (p<0.05). Cookies with aronia extract showed higher antioxidant activity compared to that with blackberry (p<0.05), due to the presence of higher content of polyphenol. In terms of appearance, flavor, taste, texture and overall acceptability, the sensory evaluation scores of cookies with 20% aronia and 10% blackberry were significantly higher compared to the control (p<0.05). Based on above result, using more than 10% of the aronia or blackberry extracts would appropriate for making cookies.

For the development of processed food for hypoglcemia, it is important to construct model system to confirm factors that reduce the glycemic index in real food. This study was to investigate the relationship between the gel model system and real food the high amylose type of segoami using response surface methodology. The independent variables were concentration (X1; 10, 15, 20, 25, and 30%) and steaming time (X2; 30, 35, 40, 45, and 50 min). The predicted glycemic index (Y1) was analyzed as a dependent variable. The regression of pGI was 0.7343, indicating that the model fits the data well in the prediction test. The predict glycemic index of the gel was in the range of 71.38 ~ 83.78, depending on the gel preparation conditions and predicted optimum condition was 23.7% gel concentration and 43.8 minutes of gelatinization. The predict glycemic index of rice gel were decreased with an increase of gel concentration, rather than the steaming time. In order to confirm the effect on in vitro digestibility in real food, the real food (Garraedduk) was prepared by applying the optimal conditions. As a result, there was no significant difference between the predicted value (77.1) and the experiment value (76.6). This result showed that the in vitro digestibility in real food can be predicted by applying the gel model system.