The impact of sourdough addition to frozen stored wheat‐flour rolls on glycemic response in human volunteers

Abstract

AbstractThe aim of this study was to examine the effect of sourdough addition to partially baked and frozen (PBF) wheat rolls on the glycemic index (GI). The study was performed on healthy humans (n = 15). The volunteers were asked to attend six times in the early morning, over 3 weeks. Each human tested four types of wheat rolls – two without sourdough addition: (i) fully baked, non‐frozen (FBNF); (ii) PBF; and two with the addition of 3% dehydrated sourdough: (iii) FBNF (FBNF + S), (iv) PBF (PBF + S). Glucose solution was used as a reference food and tested twice. Blood glucose concentrations were measured before consumption, as well as at 15, 30, 45, 60, 90, and 120 min after the start of the meal. In the study, the addition of 3% dehydrated sourdough to fresh and frozen wheat rolls resulted in a significant decrease in the glycemic response, by 24% – FBNF + S (GI = 63 ± 7) and PBF + S (GI = 43 ± 4) – compared to the samples without sourdough: FBNF (GI = 87 ± 11), PBF (GI = 67 ± 3) (p ≤ 0.05). Both factors (freezing and sourdough), applied to the wheat rolls at the same time, statistically significantly reduced the GI, by 44% (p ≤ 0.05). The results of the study show that sourdough supplementation separately and sourdough supplementation combined with frozen storage of white wheat rolls have a significant impact on the glycemic response.