Meeting Abstract - Poster Presentation

The effects of Condensed Tannins (CTs) and grain hardness on starch digestibility and Estimated Glycemic Index (EGI) of sorghum porridges
D. AUSTIN (1), L. W. Rooney (1), C. M. McDonough (1)
(1) Texas A&M University, College Station, TX, USA
Cereal Foods World 52:A35

The effects of CTs and endosperm structure on starch digestibility of porridges of 5 Sorghum [Sorghum bicolor (L.) Moench] varieties with different levels of CTs and grain hardness were evaluated. Grain hardness was evaluated by Single Kernel Hardness Test (SKHT). White sorghum (hardness of 57.73), black sorghum (hardness of 55.64), high tannin sorghum (hardness of 50.66), black with tannin (hardness of 42.31), and sumac sorghum (hardness of 37.87) varieties were used. Total starch (TS), resistant starch (RS), and digested total starch (DTS) were measured using enzymatic hydrolysis. The in-vitro rate of starch digestion was used to estimate the GI of the porridges. Also, total phenols and condensed tannins were measured. Significant negative correlations (r = –0.612, P = 0.007) were observed between grain hardness and CTs content, respectively. CTs content was also highly correlated (r = 0.96, P = 0.00) with RS. Harder endosperm sorghum varieties with CTs had significantly lower DTS (62.06%) and EGI (85.7) than soft endosperm sorghum varieties with CTs, which are DTS (72.9%), and EGI (95.15). This information can be useful for selecting sorghum varieties with relatively lower starch digestibilities for sorghum products.