Functional beverages with baobab significantly reduced the glycemic response to eating white bread, with the effects linked to the fiber and polyphenol content of baobab.
In addition, adding the baobab fruit extract to white bread led to a reduction in rapidly digestible starch from white bread samples, according to findings published in Nutrition Research.
“The baobab fruit is a rich source of bioaccessible polyphenols, and the current study shows the potential of baobab for reducing the glycemic response to carbohydrate-rich foods both in vitro and in vivo,” wrote researchers from Oxford Brookes University (UK) and Monash University (Australia).
Out of Africa
Baobab is the large green or brown fruit of the Adansonia digitata, (or 'upside-down') tree, which grows primarily in South Africa, Botswana, Namibia, Mozambique and Zimbabwe.
On pollination by fruit bats, this tree produces large green or brownish fruits. Different parts of the fruit are a traditional food in these countries.
The fruit pulp of the baobab is said to have an antioxidant activity about four times that of kiwi or apple pulp. The main nutrients include vitamin C, riboflavin, niacin, pectin and citric, malic and succinic acids, while the oil also contains the vitamins A, D and E.
The pulp is also reported to be prebiotic and stimulate the intestinal microflora.
Randy Kreienbrink, VP of Marketing with BI Nutraceuticals, told NutraIngredients-USA that the study supports all of the information and studies that the company had encountered about baobab.
"Baobab's fiber and polyphenol content, along with its long history of use as a medicinal food in Africa, add to its consumer appeal and continues to make it an ingredient to watch in the future," said Kreienbrink. "This study only further corroborates Baobab's health value. BI is a current supplier of Baobab and has incorporated this unique ingredient in several beverage applications. This well-rounded ingredient not only boosts the nutritional profiles of beverages, but the nutritional profiles of dairy products, baked goods, confections and supplements as well."
Results of the new study showed that beverages containing baobab reduced the glycemic response to white bread, with low (18.5 grams of fruit per 250 mL serving) and high (37 grams of baobab per 250 mL serving) doses producing an effect.
The high dose drink was found to reduce the glycemic response more over the first 60 minutes, whereas the lower dose reduce the glycemic response to white bread the most over 180 minutes.
The researchers also studied the effect of baobab when baked into white bread. Results from that starch breakdown and sugar release was reduced when baobab was used in the bread formulation.
“Baobab is rich in compounds such as high-molecular-weight tannins, which may be interfering with starch degradation,” wrote the researchers. “The polyphenols in the extract may be inhibiting digestive enzymes such as α-amylase and alpha-glucosidase, thereby preventing the breakdown of starch.
“However, the exact polyphenol composition of the baobab fruit is currently unknown, and further work is required to understand how these polyphenols may be exerting their effect.”
Baobab’s soluble fiber content may also have contributed to the reduction in sugar release, they added.
“Further human studies on glycemic response would be essential for determining the optimal dose of baobab fruit extract in reducing postprandial glycemia,” they concluded.
Baobab fruit has a long history of traditional use in Africa, but is only a recent entrant to more mature markets: Novel foods approval in Europe came in July 2008.
Market research firm Mintel predicted that the ingredient would enjoy almost instant success in the European market, but the novel foods approval was followed by limited uptake during 2009.
US GRAS approval was granted in September 2010.
Source: Nutrition Research
Published online ahead of print, doi: 10.1016/j.nutres.2013.08.002
“The polyphenol-rich baobab fruit (Adansonia digitata L.) reduces starch digestion and glycemic response in humans”
Authors: S.A. Coe, M. Clegg, M. Armengol, L. Ryan