Nutritional Features and Bread-Making Performance of Wholewheat: Does the Milling System Matter?

Abstract

Despite the interest in stone-milling, there is no information on the potential advantages of using the resultant wholegrain flour (WF) in bread-making. Consequently, nutritional and technological properties of WFs obtained by both stone- (SWF) and roller-milling (RWF) were assessed on four wheat samples, differing in grain hardness and pigment richness. Regardless of the type of wheat, stone-milling led to WFs with a high number of particles ranging in size from 315 to 710 μm), whereas RWFs showed a bimodal distribution with large (>1000 μm) and fine (<250 μm) particles. On average, the milling system did not affect the proximate composition and the bioactive features of WFs. The gluten aggregation kinetics resulted in similar trends for all SWFs, with indices higher than for RWFs. The effect of milling on dough properties (i.e., mixing and leavening) was sample dependent. Overall, SWFs produced more gas, resulting in bread with higher specific volume. Bread crumb from SWF had higher lutein content in the wheat cv rich in xanthophylls, while bread from RWF of the blue-grained cv had a moderate but significantly higher content in esterified phenolic acids and total anthocyanins. In conclusion, there was no relevant advantage in using stone- as opposed to roller-milling (and vice versa).

Keywords: bioactive compounds; bread; dough rheology; pigmented wheat; roller milling; stone milling; wholewheat flour.

Figure 1

Effect of stone milling (black bars) and roller milling (dash bars) on the particle size distribution of whole grain flours from Bolero cv (a), CWRS (b), Bona Vita cv (c) and Skorpion cv (d). CWRS: commercial Canada Western Red Spring Wheat.

Figure 2

Effect of stone milling (solid line) and roller milling (dash line) on gluten aggregation properties, assessed by GlutoPeak^®, of whole grain flours from Bolero cv (a), CWRS (b), Bona Vita cv (c) and Skorpion cv (d). CWRS: commercial Canada Western Red Spring Wheat; GPU: GlutoPeak Units.

Figure 3

Effect of stone milling (solid line) and roller-milling (dash line) on the mixing properties, assessed by Farinograph^®, of whole grain flours from Bolero cv (a), CWRS (b), Bona Vita cv (c) and Skorpion cv (d). CWRS: commercial Canada Western Red Spring Wheat; FU: Farinographic Units.

Figure 4

Effect of stone milling (solid line) and roller milling (dash line) on dough development, assessed by Rheofermentometer^®, during leavening of whole grain flours from Bolero cv (a), CWRS (b), Bona Vita cv (c) and Skorpion cv (d). CWRS: commercial Canada Western Red Spring Wheat.

Figure 5

Effect of stone milling (solid line) and roller milling (dash line) on the total gas production (grey line) and on the retained gas (black line) in the dough, assessed by Rheofermentometer^®, of whole grain flours from Bolero cv (a), CWRS (b), Bona Vita cv (c) and Skorpion cv (d).

Figure 6

Effect of stone and roller milling on bread height (H; cm), volume (V; mL) specific volume (SV; mL/g). Data are presented as mean ± standard deviation. The asterisks indicate significant differences between the mean of the bread from stone and roller milled flours of each cvs (* p < 0.01). The absence of asterisk indicates a not significant difference. CWRS: commercial Canada Western Red Spring Wheat.