Effects of bran size and carob seed flour of optimized bread formulas on glycemic responses in humans: A randomized clinical trial

Abstract

We investigated the glycemic-index (GI), glycemic-load (GL) and glycemic response to four breads produced by optimized formulas in terms of texture and structure: white bread (WB), bread enriched with coarse wheat bran (CB), with fine wheat bran (FB) and FB with 10% carob-seed flour (CSFB). Ten healthy individuals (24 ± 1 years; BMI 22 ± 3 kg/m2) received isoglucidic test meals (50 g available carbohydrate) and 50 g glucose reference, in random order. GI/GL was calculated and capillary blood glucose and salivary insulin samples were collected at 0–120 min after meal consumption. CB and CSFB provided medium-GI, low-GL. WB and FB provided high-GI, medium-GL. Peak glucose value was lower for CSFB (p = 0.03). Dough water content was inversely associated with GI (p = 0.03). No differences were observed between breads for fasting glucose, fasting and post-test-meal insulin concentrations. Larger bran particle size and flour substitution by carob-seed flour attenuated the glycemic response resulting in lower GI or GL breads.