Effect of Pinto Bean Starch Fortification on Bread Texture and Expected Glycemic Index

Abstract

Pulse starches are known to have a low glycemic index due to their unique starch conformation and high amylose content. Hence, pinto bean starch (PBS) was extracted from pinto beans and added to bread formulations at 0% (control), 5%, 10%, and 15% concentrations. Texture profile analysis (TPA) on the loaves was completed 24 hours after baking. Following TPA, the breads were analyzed to determine their starch hydrolysis profiles and expected glycemic index (eGI). TPA results showed that inclusion of native PBS in bread did not significantly alter textural characteristics (hardness, springiness, and chewiness), except for cohesiveness which was significantly lower in the bread loaves containing PBS (0.52 – 0.54) compared to the control (0.61). The addition of native PBS (eGI = 37.5) significantly reduced eGI in bread loaves by approximately 2%. However, the final eGI was still within the range considered to be high GI (>70). The findings demonstrated that pinto bean starch may be added to bread to reduce eGI without significantly altering textural properties.