Healthier, diabetic-friendly bread

28 Mar 2016 NUS food scientists have shown that fortifying bread with anthocyanin-rich extract slows down its digestion rate and adds health benefits.

Anthocyanins are naturally occurring pigments in some fruits and vegetables. One of the well-known health-promoting properties of anthocyanins is their antioxidant activity. Furthermore, anthocyanins can inhibit digestive enzymes, which helps reduce the increase in blood glucose level from digesting starch[1]. However, knowledge of using anthocyanins as an active ingredient in real food systems is very limited. Thus, a team led by Prof ZHOU Weibiao from the Food Science & Technology Programme at the Department of Chemistry in NUS aimed to create a bread product fortified with anthocyanin-rich extract from black rice. This may lead to new opportunities to produce functional bread by slowing down its digestion rate, thereby providing extra health benefits to consumers[2].

In general, bread is a carbohydrate-rich product, which contains a high amount of rapidly digestible starch. Many types of bread, particularly white bread, have a high glycemic index (GI). Due to the rapid digestion of bread, people may consume more bread than their body requires to abate hunger[3]. The excessive consumption of bread could increase the risk of obesity, and associated diseases, such as Type II diabetes[4]. Bread fortified with anthocyanin-rich extract has a slower digestion rate that may help improve blood glucose control and may provide an alternative, tasty product for diabetics.

While their research demonstrated the slow digestion property of bread fortified with anthocyanin-rich extract, in vivo testing of the bread’s GI value may be conducted to provide further confirmation. Fortification of anthocyanin-rich extract in other types of food, e.g. biscuits, can be carried out to expand knowledge of the functionalities of anthocyanins in real food systems.

The researchers have conducted in vitro and in silico studies to demonstrate the inhibition activity of the four major anthocyanins found in black rice extract against alpha-amylase, which may be a main factor that is responsible for the slower digestion rate of bread fortified with anthocyanin-rich extract[5].


Figure shows freshly baked anthocyanin-fortified bread [Image credit: NUS].



1. Matsui T, Ueda T, Oki T, Sugita K, Terahara N, Matsumoto K. “Α-Glucosidase inhibitory action of natural acylated anthocyanins. 1. Survey of natural pigments with potent inhibitory activity.” Journal of Agricultural and Food Chemistry. 49 (2001) 1948.

2. Sui X, Zhang Y, Zhou W. “Bread fortified with anthocyanin-rich extract from black rice as nutraceutical sources: Its quality attributes and in vitro digestibility.” Food Chemistry. 196 (2015) 910.

3. Therdthai N, Zhou W. “Manufacture. In W. Zhou & Y. H. Hui (Eds.), Bakery products science and technology.” 2nd ed (2014) 473.

4. Bueno JM, Sáez-Plaza P, Ramos-Escudero F, Jiménez AM, Fett R, Asuero AG. “Analysis and antioxidant capacity of anthocyanin pigments. Part II: Chemical structure, colour, and intake of anthocyanins.” Critical Reviews in Analytical Chemistry. 42 (2012) 126.

5. Sui X, Zhang Y, Zhou W. “In vitro and in silico studies of the inhibition activity of anthocyanins against porcine pancreatic alpha-amylase.” Journal of Functional Foods. 21 (2016) 50.