Bread is a staple food that is traditionally made from wheat flour. Researchers from National University of Singapore published on Food Chemistry journal a study where the starch digestibility of western baked bread and oriental steamed bread were compared in order to investigate how macronutrient composition and processing conditions could influence GI. 

Four types of bread were prepared: western baked bread (WBB) and oriental steamed bread (OSB), modified baked bread (MBB) made with the OSB recipe and WBB processing, and modified steamed bread (MSB) made with the WBB recipe and OSB processing. MBB showed the highest starch digestibility in vitro, followed by WBB, OSB and MSB. A similar trend was observed for glycaemic response in vivo. MBB, WBB, OSB and MSB had a glycaemic index of 75 ± 4, 71 ± 5, 68 ± 5 and 65 ± 4, respectively. Processing differences had a more pronounced effect on starch digestibility in bread, and steamed bread was healthier in terms of glycaemic response.

The manipulation of processing conditions could be an innovative route to alter the glycaemic response of carbohydrate-rich foods.