Green tea catechins reduced the glycaemic potential of bread: An in vitro digestibility study

• GTE reduced the glycemic potential of both baked and steamed bread.
• GTE reduced glucose release during first 90 min of in vitro digestion of bread.
• The reduction was significant for both steamed and baked bread.
• Bread containing 2% GTE exhibited a significantly lower RSD content.
• The GTE amount present in bread was significantly correlated with the RDS content.

Green tea catechins are potent inhibitors of enzymes for carbohydrate digestion. However, the potential of developing low glycaemic index bakery food using green tea extract has not been investigated. Results of this study showed that addition of green tea extract (GTE) at 0.45%, 1%, and 2% concentration levels significantly reduced the glycaemic potential of baked and steamed bread. The average retention levels of catechins in the baked and steamed bread were 75.3–89.5% and 81.4–99.3%, respectively. Bread fortified with 2% GTE showed a significantly lower level of glucose release during the first 90 min of pancreatic digestion as well as a lower content of rapidly digested starch (RDS) content. A significantly negative correlation was found between the catechin retention level and the RDS content of bread. The potential of transforming bread into a low GI food using GTE fortification was proven to be promising.