Effects of dietary fibres, polyphenols and proteins on the estimated glycaemic index, physicochemical, textural and microstructural properties of steamed bread

Summary The effects of dietary fibres, polyphenols, proteins and their combination on the estimated glycaemic index (eGI) of steamed bread, as well as the specific volume, height‐to‐diameter ratio, textural and microstructural properties thereof were studied. The results showed that supplementation of 7% soybean dietary fibre, 10% gallic acid combined with 25% soybean protein isolate significantly reduced the starch digestibility of wheat steamed bread, as evidenced by the significant decrease of eGI value from 88.16 to 49.16, which was classified as low GI steamed bread. While, the addition of soybean dietary fibre, gallic acid and soybean protein isolate together negatively affected the fermentation properties of dough, resulting in lower specific volume, chewiness, springiness and higher hardness of steamed bread compared to wheat bread without any addition. The above results in this study might provide theoretical guidance for the development of healthier and blood glucose‐friendly steamed bread in the staple food industry.