Effect of a low molecular weight, high-purity β-glucan on in vitro digestion and glycemic response

Abstract

β-Glucans are believed to lower postprandial glycemia due to their ability to increase viscosity and slow down gastric emptying. The effect of high-purity barley β-glucan (Glucagel™) was tested on in vitro starch digestibility and glycemic response of chapattis. In a randomized controlled crossover trial, 10 healthy human subjects consumed chapattis containing 0, 4 and 8% β-glucan on different occasions. Capillary blood samples were collected before and at 0, 15, 30, 45, 60, 90 and 120 min after consuming the chapattis. There was no significant difference either in the amount of glucose released after in vitro digestion or in the glycemic response to chapattis with 0, 4 and 8% β-glucan (P>0.05). It may be concluded that low molecular weight barley β-glucan, although of 75% purity, was not effective in lowering glycemic response possibly due to its inability to influence starch digestion and particle breakdown during in vitro digestion.

Keywords::

• Barley
• β-glucan
• flatbreads
• glycemic response
• in vitro starch digestion

Acknowledgements

The authors thank Tom Jorgens (PolyCell Technologies, MN, USA), Kavan Ranasinghe and Simon Williams (DKSH, London, UK) for providing Glucagel™. The authors also thank John Monro (The New Zealand Institute for Plant & Food Research Limited, Palmerston North, New Zealand) for his help in the development of in vitro digestion model, Megan Pratt for laboratory assistance and all the participants for their cooperation in the glycemic response study.

Declarations of interest: The present study was funded by the Higher Education Innovation Fund. The authors have no conflicts of interest.