Unraveling the Food Matrix Components Underlying Glycemic Response in Yellow Popcorn Hybrids (Zea mays var. 'Everta')

Most popcorn studies have focused on individual components, while the interactions among phytochemicals, particle size, and glycemic response remain poorly understood. This study evaluated five popcorn hybrids and one commercial sample, expanded by hot air and separated into fine and coarse fractions, to identify matrix components associated with estimated glycemic index (eGI). In vitro eGI, dietary fiber, antioxidant activity, phenolics, hydroxycinnamic acid amides (HCAA), and phytosterols were evaluated. Hybrids showed low eGI values (45.6-48.3) compared with commercial popcorn, while Popcorn 2 exhibited the highest soluble dietary fiber and lowest eGI. Significant differences in phenolics, HCAA, and phytosterols were observed among samples and particle-size fractions. Free and bound phenolics and phytosterols were predominantly concentrated in fine fractions, whereas HCAA were generally higher in coarse fractions. Bound p-coumaric acid (469 μg/g), ferulic acid (6264 μg/g), and HCAA (up to 1304 μg/g) were higher in fine fractions. β-Sitosterol reached 94.3 μg/g in the fine fraction of Popcorn 5. Free phenolics correlated positively with eGI, suggesting that individual phytochemicals do not independently explain glycemic differences. The eGI variation among popcorn hybrids appears to reflect the combined influence of dietary fiber, particle size, and overall matrix composition rather than individual components.