Plant pigment ingredient bakes healthier bread

The addition of a natural plant pigment — anthocyanin — extracted from black rice causes bread to be digested at a slower rate, improving blood glucose control. The final product is also high in antioxidants.

The anthocyanin-fortified bread has been created by researchers from the National University of Singapore (NUS) and could potentially bring health benefits to consumers — including sufferers of diabetes — who are looking for a healthier alternative to normal bread.

Anthocyanins belong to the group of flavonoids that are naturally occurring pigments in fruits, such as blueberries, as well as grains and vegetables like black rice and purple sweet potatoes. They are responsible for the orange, red, violet and blue colours observed in nature.

Scientific studies have shown that anthocyanins are rich in antioxidant properties and may help prevent cardiovascular and neurological diseases, cancer and inflammation. Anthocyanins can also inhibit digestive enzymes, hence reducing blood glucose levels.

Dr Sui Xiaonan, a recent PhD graduate from the Food Science and Technology Programme at NUS and first author of the study, said, “Reducing the digestion rate of the bread will lead to a lower glycaemic index and slower absorption of the bread’s carbohydrates. This usually suggests a lower insulin demand, and could potentially improve long-term blood glucose control.”

The researchers found that digestion rates of the anthocyanin-fortified bread reduced by 12.8% when 1% of anthocyanin extract was added into the bread dough and baked at the optimal condition of 200°C for 8 minutes. The digestion rate dropped further to 20.5%, with 4% of anthocyanin extract.

The team had previously conducted a study in 2014 to examine the degradation of anthocyanins during baking. They found that more than 80% of the antioxidant capacity was retained in the bread crust and crumb, even when baked at temperatures as high as 240°C for up to 12 minutes.

The research findings were published in the journal Food Chemistry.