Barley beta-glucan in bread: The journey from production to consumption.

摘要

beta-Glucan is a soluble fibre shown to help regulate blood sugar and lower cholesterol. Incorporation into food, particularly bread, may affect beta-glucan's physicochemical properties and health benefits. The journey of beta-glucan through the mixing, fermenting, baking, and storage of bread was evaluated, in terms of its solubility and viscosity under in vitro physiological conditions, at levels most likely to be presented to consumers (0.75, 1.0, 1.5 g beta-glucan/serving). Satiety and glycemic response measures, in addition to the quality and consumer acceptability of the bread, were also investigated.;Baking increased beta-glucan solubilization to 58-60%, compared to 9% in dough. Gluten addition increased solubility further (67-68%). Similar trends were seen for extract viscosity and were supported by fluorescence microscopy images. Storage at ambient, refrigeration and frozen conditions showed that bread with beta-glucan should be consumed fresh to maintain highest bread quality and beta-glucan solubility and viscosity.;Bread with beta-glucan kept panelists full, longer. Reducing sugar release values implied that satiety may depend on digesta viscosity and/or rate of sugar release from the bread. Bread with beta-glucan produced the most leveled glucose curve; though areas under the 2 hr plasma glucose curves were similar. Consumers liked the 0.75 g beta-glucan/serving bread and the control more than the 1.5 g beta-glucan/serving bread, though provision of health information improved bread liking to similar values.;The findings demonstrate that low solubility beta-glucan concentrate that gets solubilized upon baking is well suited for bakery applications and that a successful beta-glucan-fortified bread product is possible. Commercialization of bread fortified with beta-glucan would provide consumers an additional source of dietary fibre to assist them in coming closer to recommended daily intakes.;In dough, viscosity of the physiological extract was impacted by beta-glucan level, fermentation time, and endogenous flour enzymes. Fermentation decreased beta-glucan solubility indicating that the reduction in viscosity depends on both molecular degradation and solubility reduction. Dough rheological properties and microstructure, characterized using an oscillatory rheometer and fluorescence microscopy, respectively, showed that beta-glucan may interfere with the gluten network, though gluten addition may help improve this. The bread's physical properties supported these observations, as beta-glucan decreased loaf volume and height, while gluten addition corrected this.