A team of food scientists from the National University of Singapore (NUS) has successfully formulated a recipe for making healthier bread by adding a natural plant pigment, called anthocyanin, extracted from black rice. This new bread option gets digested at a slower rate — hence improving blood glucose control — and is high in antioxidants, among other health benefits.
This is the first study where anthocyanin extract has been fortified into a bread product, and the findings open up new possibilities of creating healthier, diabetic-friendly food products.
Bread is a popular staple food for many people around the world. Most breads contain a high amount of rapidly digestible starch and, hence, a high glycemic index, making them unsuitable for diabetic patients. The excessive consumption of bread could increase the risk of overweight and obesity, and their associated diseases, such as Type II diabetes.
The anthocyanin-fortified bread created by NUS researchers could potentially bring health benefits to consumers looking for a healthier option to normal bread. The research findings were published in the journal Food Chemistry in October 2015.
Anthocyanins belong to the group of flavonoids that are naturally occurring pigments in fruits, such as blueberries, as well as grains and vegetables such as 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.
Professor Zhou Weibiao, Director of the Food Science and Technology Programme at the NUS Faculty of Science, said: “Despite their benefits, the knowledge of using anthocyanins as an ingredient in food products, particularly semi-solid products, is very limited. Hence, we wanted to explore the feasibility of fortifying anthocyanins into bread, to understand how it affects digestibility and its impact on the various quality attributes of bread.”
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 glycemic 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 NUS team, led by Prof. Zhou, 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 degrees Celsius for 8 minutes. The digestion rate dropped further to 20.5% with a 4% anthocyanin extract.
The team also wanted to explore incorporating anthocyanins into bread to improve its value as a health-promoting food. They 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 degrees Celsius for up to 12 minutes.
“Our results demonstrate that it is indeed feasible to create functional food products through anthocyanin fortification, using bread as an example. We hope to conduct further studies to incorporate anthocyanins into other food items, such as biscuits. Our team is also keen to explore opportunities to work with industry partners to introduce the anthocyanin-fortified bread to the market,” Prof Zhou said.