title: Impact of the molecular weight, viscosity, and solubility of β-glucan on in vitro oat starch digestibility.
abstract: The impacts of the molecular weight (MW), viscosity, and solubility of β-glucan on the rate of in vitro starch digestion and estimated glycemic index (GI) were evaluated. Extracted oat starch and β-glucan suspensions with high, medium, and low MW were heated to gelatinize the starch. The viscosity increased and the solubility decreased with an increase in the MW of β-glucan. The in vitro starch hydrolysis of the mixtures and a control, white bread, increased as the digestion time increased. As the MW of β-glucan increased, the starch hydrolysis decreased during in vitro digestion. The in vitro estimated GI of the mixture without β-glucan, determined from the starch hydrolysis rate, was 88.3 for Jim and 80.0 for N979, which decreased to 68.4 and 66.8, respectively, with the inclusion of high-MW β-glucan. The estimated GI values were negatively correlated with the β-glucan peak and final viscosities (r = -0.81 and -0.82). These results illustrated the importance of viscosity attributed to the β-glucan MW on starch hydrolysis during in vitro digestion. These findings will help to develop new food products with a low GI by using oat β-glucan.
authors.affiliation: Department of Food Bioengineering, Jeju National University, Jeju, Republic of Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.forename: Pamela J
authors.initials: PJ
authors.lastname: White
mesh_terms: D018554:Avena / Q000737:chemistry*; D038321:Glycemic Index; D006868:Hydrolysis; D066298:In Vitro Techniques; D008970:Molecular Weight; D012995:Solubility; D013213:Starch / Q000737:chemistry*; D014783:Viscosity; D047071:beta-Glucans / Q000737:chemistry*
chemical_list: D047071:beta-Glucans; D013213:Starch