In vitro starch digestibility and predicted glycemic index of microwaved and conventionally baked pound cake

The present study compares the effect of baking process (microwave vs conventional oven) on starch bioavailability in fresh pound cake crumbs and in crumbs from pound cake stored for 8 days. Proximal chemical analysis, resistant starch (RS), retrograded starch (RS3) and starch hydrolysis index (HI) were evaluated. The empirical formula suggested by Granfeldt was used to determine the predicted glycemic index (pGI). Pound cake, one of Mexico's major bread products, was selected for analysis because the quality defects often associated with microwave baking might be reduced with the use of high-fat, high-moisture, batted dough. Differences in product moisture, RS and RS3 were observed in fresh microwave-baked and conventionally baked pound cake. RS3 increased significantly in conventionally baked products stored for 8 days at room temperature, whereas no significantly changes in RS3 were observed in the microwaved product. HI values for freshly baked and stored microwaved product were 59 and 62%, respectively (P > 0.05), whereas the HI value for the conventionally baked product decreased significantly after 8 days of storage. A pound cake with the desired HI and GI characteristics might be obtained by adjusting the microwave baking process.