Glycemic response and starch digestibility in traditional and industrial breads from the Galician market (NW Spain)

Abstract

In Galicia, bread is not only a dietary staple but also a cultural and high-value product. The increasing replacement of traditional bread by industrial alternatives has raised nutritional concerns. This study assessed in vitro starch digestibility and estimated glycemic index (eGI) in 72 breads from the Galician market, including industrial and artisan traditional samples made with wheat, rye, or corn. Significant differences (p < 0.05) were observed across samples in terms of starch fractions and glycemic index. Traditional breads made with local corn or rye flours showed lower eGI values and higher resistant starch contents, whereas industrial wheat breads exhibited higher eGI and rapidly digestible starch fractions. Both compositional and technological factors influenced glycemic response, including cereal type, sourdough use, and fermentation duration. Overall, traditional breads produced with local flours and long fermentation displayed a slower starch digestibility pattern and more favorable nutritional profile than industrial counterparts, supporting their promotion as healthier options within a balanced diet.