Effects of Mineral Vitamin Premixes on Dough Mixing and Bread Properties in White and Wholemeal Wheat Formulations

1. Introduction

Wheat flour composition affects dough mixing and bread structure. Wholemeal flour retains bran and germ fractions that differ from refined flour in fibre, ash and micronutrient content. Added premixes also introduce salts, vitamin preparations and carrier material; their combined effects on mixing behaviour and bread quality require assessment in the formulation as used.

Wholemeal dough behaviour varies with cultivar, flour particle size and bran content. Studies have reported effects on water distribution, gluten structure and bread volume, but the direction and magnitude depend on the flour and process [1,2,3,4]. Bran micronisation, extrusion and aqueous extraction alter bran functionality in different ways [5,6,7]. Breadmaking studies also show that particle size, dough development and improver choice influence the final structure [8,9,10].

Farinograph measurements describe dough behaviour during mixing, while volume and crumb measurements describe properties of the finished bread. Comparing premix formulations in two flour matrices can reveal formulation-associated differences. It cannot attribute an observed response to a single premix component without appropriate component controls.

Studies involving mineral-enriched wheat and fortified bread provide useful comparisons, although agronomic biofortification differs from direct addition of a premix [11,12]. Vitamin D3 and fibre fortification has likewise shown that nutrient addition and technological quality must be assessed together [13]. Salt composition and dried sourdough can modify mixing behaviour and bread characteristics, so their contribution to formulation effects must be considered [14,15,16].

Sourdough effects vary with the fermentation system, flour and whether the ingredient is used fresh or dried. Recent studies report changes in dough and bread properties under different sourdough processes [17,18,19]. Flour extraction rate can also interact with sourdough fermentation [20]. These findings provide context for the present dried-sourdough formulations without implying the same microbial activity or process conditions [21].

Two comparisons are especially relevant to the design. First, the same premix was introduced into flours with different bran and protein characteristics; any change in farinograph behaviour must therefore be read against its flour-specific control. Second, dried sourdough was incorporated in both plain and premix formulations, allowing finished-bread properties to be compared within each flour group. The latter comparison does not identify active fermentation by the dried ingredient. Studies of live and dried sourdough illustrate why product type and processing conditions should be reported separately [18,21].

The objective was to compare dough mixing characteristics and the physical, proximate, sensory and micronutrient properties of 12 bread formulations. Nutrient retention and bioavailability were outside the scope of the measurements presented here.

2. Materials and Methods

2.1. Ingredients and Formulations

Experiments were conducted at the Cereal and Flour Processing Pilot Station of the National Research and Development Institute for Food Bioresources (INCDBA IBA), Bucharest, Romania. White type 650 and wholemeal wheat flours were supplied by Șapte Spice. Their stated characteristics were, respectively, protein 12.38% and 14.25%, wet gluten 28.40% and 25.00%, falling number 323 and 486 s, and moisture 13.80% and 11.70%. Fresh baker’s yeast, iodised salt and Spring Pane dried sourdough were also used.

Table 1. Raw materials reported for the bread formulations.

Usage	Supplier	Raw material
White bread variants	S.C. 7 Spice S.R.L.	White wheat flour (type 650)
Wholemeal bread variants	S.C. 7 Spice S.R.L.	Whole-grain wheat flour
All variants	Metro Cash & Carry	Fresh baker’s yeast
All variants	Metro Cash & Carry	Iodised table salt
V2, V4, V7, V9	S.C. Orkla S.R.L.	Mineral-vitamin Premix 1
V3, V5, V8, V10	S.C. Orkla S.R.L.	Mineral-vitamin Premix 2
V4, V5, V9, V10, V11, V12	S.C. Orkla S.R.L.	Dried sourdough (Spring Pane)

Table 1. Raw materials reported for the bread formulations.

Usage	Supplier	Raw material
White bread variants	S.C. 7 Spice S.R.L.	White wheat flour (type 650)
Wholemeal bread variants	S.C. 7 Spice S.R.L.	Whole-grain wheat flour
All variants	Metro Cash & Carry	Fresh baker’s yeast
All variants	Metro Cash & Carry	Iodised table salt
V2, V4, V7, V9	S.C. Orkla S.R.L.	Mineral-vitamin Premix 1
V3, V5, V8, V10	S.C. Orkla S.R.L.	Mineral-vitamin Premix 2
V4, V5, V9, V10, V11, V12	S.C. Orkla S.R.L.	Dried sourdough (Spring Pane)

According to the manufacturer’s technical specifications [22], Premix 1 contained, per 100 g, 6.50 mg Dry Vitamin D3 100 CWS, 4.68 g Dry Vitamin E 50 CWS, 22 mg sodium selenite and 3.90 g zinc sulphate monohydrate. Premix 2 contained 13.00 mg, 3.25 g, 16.25 mg and 4.55 g of the respective preparations and salts per 100 g. Wheat flour was listed as carrier. These are ingredient target amounts in the specification, not measured elemental zinc and selenium or assayed active-vitamin contents.

2.2. Experimental Design and Breadmaking

Two flour types, three premix conditions (none, Premix 1 and Premix 2) and two dried-sourdough conditions (absent or present) gave 12 formulations (Table 2). Table 3 provides the recorded ingredient percentages by dough mass. One summary value is presented per formulation; separate observations from individual production batches are not tabulated.

Bread was made by a direct process with or without dried sourdough. The formulation record specifies dried sourdough at 1.44–1.63% of dough mass (approximately 2.6–2.8% relative to flour) and premix at 0.06% of dough mass (approximately 0.10% relative to flour). Mixing lasted 5 min in a Diosna mixer, followed by 60 min bulk fermentation at 30 °C and 80% relative humidity, 20 min final proofing and 20 min baking in a fixed-hearth oven set to 235 °C.

2.3. Dough and Bread Analyses

Dough water absorption, development time, stability, degree of softening and FQN were determined with a Brabender Farinograph-E at 500 BU using the stated ICC 115/1 and SR EN ISO 5530-1:2015 methods. Triplicate determinations were reported. The displayed summary values cover control and Premix 2 doughs for both flour types; individual farinograph readings are not tabulated.

Bread moisture, protein, ash, crude fibre, porosity, crumb elasticity, volume per 100 g and titratable acidity were determined by the stated laboratory procedures. Protein was measured by Kjeldahl analysis. Zinc and selenium were measured by ICP-MS after calcination and sample preparation. Vitamin D was analysed by the PN-EN 12821:2009 method and vitamin E by the PB-40/HPLC method. Some determinations were repeated on the same sample; technical repeats are not treated as independent production batches. The tables present the available summary concentrations without analytical uncertainty estimates or individual readings.

2.4. Sensory Assessment and Data Handling

Nine trained assessors evaluated white- and wholemeal-flour samples in separate sessions using a 0–5 intensity scale for visual, structural, aroma and taste attributes. Preference ranking was also recorded. The available results consist of attribute summaries; they represent sensory profiling by the panel rather than consumer acceptance.

Tables present the recorded summary values. Differences are interpreted descriptively; no p values, confidence intervals or between-batch standard deviations are assigned. Percentage changes calculated from table entries are arithmetic comparisons only.

3. Results and Discussion

3.1. Farinograph Results

Premix 2 was associated with higher dough stability for both flours: 5:55 to 15:00 min for white flour and 1:56 to 9:42 min for wholemeal flour. FQN increased from 88 to 156 (+77.3%) and from 30 to 120 (+300%), respectively. Water absorption moved in opposite directions, declining by 4.9 percentage points for white flour and increasing by 8.0 points for wholemeal flour. Development time fell from 5:08 to 3:45 min in white flour and increased from 1:50 to 5:35 min in wholemeal flour. Softening declined from 61 to 30 BU in white flour but rose from 70 to 78 BU in wholemeal flour.

Table 4. Farinograph values reported for controls and Premix 2 formulations.

Wholemeal + Premix 2	Wholemeal (control)	White 650 + Premix 2	White 650 (control)	Parameter
66.50	58.50	59.40	64.30	Water absorption (WA, %)
5:35	1:50	3:45	5:08	Development time (DDT, min:ss)
9:42	1:56	15:00	5:55	Stability (S, min:ss)
78	70	30	61	Softening (DS, BU)
120	30	156	88	Farinograph Quality Number (FQN, mm)

Table 4. Farinograph values reported for controls and Premix 2 formulations.

Wholemeal + Premix 2	Wholemeal (control)	White 650 + Premix 2	White 650 (control)	Parameter
66.50	58.50	59.40	64.30	Water absorption (WA, %)
5:35	1:50	3:45	5:08	Development time (DDT, min:ss)
9:42	1:56	15:00	5:55	Stability (S, min:ss)
78	70	30	61	Softening (DS, BU)
120	30	156	88	Farinograph Quality Number (FQN, mm)

The two flours showed different patterns in water absorption, development time and softening. The available measurements describe the combined effect of Premix 2 in each flour matrix. They do not isolate the effects of zinc sulphate, sodium selenite, vitamin preparations or carrier material. Premix 1 and dried-sourdough formulations were not included in the farinograph comparison.

The opposing water-absorption responses of the two flours are consistent with the dependence of mixing behaviour on flour composition and water distribution, rather than a uniform effect of the premix. Published studies on bran fractions and their processing provide mechanistic context [2,3,23], while experiments with low-sodium salts show that mineral-containing formulations can change mixing parameters [16]. The present data do not identify which of these mechanisms operated.

The white-flour formulation displayed both a longer stability interval and lower softening after Premix 2 addition, whereas the wholemeal formulation displayed longer stability but slightly greater softening. Stability and softening therefore should not be treated as interchangeable indicators of a single strengthening effect. Their contrasting responses may reflect differences in hydration and mixing development under the 500 BU farinograph protocol. Bran fractions can bind water and change the way gluten develops, and processing of bran can alter these interactions [2,3,5]. No measurement of free water, gluten microstructure or component-specific binding was made in the present study, so those mechanisms remain contextual explanations rather than findings.

The FQN increase from 88 to 156 for white flour and from 30 to 120 for wholemeal flour is large in relative terms, but the wholemeal value starts from a much lower control. Reporting both the absolute values and their changes avoids implying that the final doughs reached the same technological state. Because only Premix 2 farinograph values are shown, the mixing results cannot rank Premix 1 against Premix 2. Similarly, the later bread comparison cannot be used as a substitute for missing farinograph measurements for the sourdough-containing doughs. Studies of whole wheat cultivar, bran level and particle size show that process and material characteristics can strongly affect dough response [4,10].

3.2. Physical and Proximate Properties of Bread

White-flour bread volumes ranged from 340 to 370 cm³/100 g, compared with 295 to 310 cm³/100 g for wholemeal bread. Relative to the plain controls, premix-only formulations had lower displayed volumes: 370 versus 355 and 360 cm³/100 g for white flour and 310 versus 305 and 308 cm³/100 g for wholemeal flour. Porosity was 82–87% in white bread and 77–79% in wholemeal bread. The magnitude and reproducibility of these differences cannot be assessed from the summary values alone.

Table 5. Reported physical and proximate bread properties for the twelve formulations.

Acidity (°)	Volume (cm³/100g)	Elasticity (%)	Porosity (%)	Fibre (%, d.b.)	Ash (%, d.b.)	Protein (%, d.b.)	Moisture (%)	Variant
1.8	370	98	87	2.5	0.81	13.86	44.1	V1 (WF ctrl)
1.8	355	97	85	2.6	0.80	13.86	43.7	V2 (WF+P1)
1.9	360	97	86	2.73	0.78	13.86	44.0	V3 (WF+P2)
2.0	345	95	83	2.6	0.82	13.86	44.48	V4 (WF+P1+SD)
2.0	340	94	82	2.5	0.83	13.86	44.2	V5 (WF+P2+SD)
2.1	310	82	79	11.62	2.03	14.25	43.5	V6 (WM ctrl)
2.1	305	85	77	11.52	2.05	14.25	43.31	V7 (WM+P1)
2.0	308	83	78	11.47	2.04	14.25	43.6	V8 (WM+P2)
2.2	300	80	77	11.40	2.08	14.82	43.8	V9 (WM+P1+SD)
2.2	295	80	77	11.33	2.10	15.82	44.1	V10 (WM+P2+SD)
1.9	360	97	86	2.5	0.83	13.86	43.9	V11 (WF+SD)
2.1	308	81	79	11.41	2.06	14.25	43.7	V12 (WM+SD)

Table 5. Reported physical and proximate bread properties for the twelve formulations.

Acidity (°)	Volume (cm³/100g)	Elasticity (%)	Porosity (%)	Fibre (%, d.b.)	Ash (%, d.b.)	Protein (%, d.b.)	Moisture (%)	Variant
1.8	370	98	87	2.5	0.81	13.86	44.1	V1 (WF ctrl)
1.8	355	97	85	2.6	0.80	13.86	43.7	V2 (WF+P1)
1.9	360	97	86	2.73	0.78	13.86	44.0	V3 (WF+P2)
2.0	345	95	83	2.6	0.82	13.86	44.48	V4 (WF+P1+SD)
2.0	340	94	82	2.5	0.83	13.86	44.2	V5 (WF+P2+SD)
2.1	310	82	79	11.62	2.03	14.25	43.5	V6 (WM ctrl)
2.1	305	85	77	11.52	2.05	14.25	43.31	V7 (WM+P1)
2.0	308	83	78	11.47	2.04	14.25	43.6	V8 (WM+P2)
2.2	300	80	77	11.40	2.08	14.82	43.8	V9 (WM+P1+SD)
2.2	295	80	77	11.33	2.10	15.82	44.1	V10 (WM+P2+SD)
1.9	360	97	86	2.5	0.83	13.86	43.9	V11 (WF+SD)
2.1	308	81	79	11.41	2.06	14.25	43.7	V12 (WM+SD)

Figure 1. External appearance and crumb sections of the 12 bread formulations. Original sample photographs were assembled with minor tonal and sharpness adjustments. Samples are ordered left to right as labelled. Photographs document appearance and are not measurements of volume or porosity.

Figure 1. External appearance and crumb sections of the 12 bread formulations. Original sample photographs were assembled with minor tonal and sharpness adjustments. Samples are ordered left to right as labelled. Photographs document appearance and are not measurements of volume or porosity.

Titratable acidity ranged from 1.8 to 2.2 in the units used by the source method. The dried-sourdough formulations generally yielded values between 1.9 and 2.2. Dry-basis protein was reported as 13.86% for all white-flour breads and 14.25–15.82% for wholemeal breads; ash was 0.78–0.83% and 2.03–2.10%, respectively. The difference between V9 and V10 protein values is presented as recorded, without assigning it to proteolysis or premix action.

Changes in bread volume associated with wholegrain fractions have also been observed in studies that manipulate bran particle size, gluten interactions and ingredient processing [5,7,10]. Thus, a higher farinograph stability in the present Premix 2 doughs should not be interpreted as proof of increased loaf volume. Studies of dried sourdough and wholemeal bread likewise indicate that mixing and product characteristics must be evaluated separately [18,19].

The volume comparison also illustrates why a stronger farinograph response should be interpreted alongside the finished loaf. In white flour, the premix-only formulations V2 and V3 gave 355 and 360 cm³/100 g against 370 cm³/100 g for V1, differences of approximately 4.1% and 2.7%. In wholemeal flour, V7 and V8 gave 305 and 308 cm³/100 g against 310 cm³/100 g for V6, differences of approximately 1.6% and 0.6%. These calculations use the displayed values and have no associated uncertainty interval. Mixing resistance, gas production, gas retention, proofing behaviour and oven expansion can each affect final volume. The reported measurements do not identify which stage accounts for the observed differences.

The sourdough-containing variants offer a further descriptive comparison. For white flour, volumes of V4 and V5 were 345 and 340 cm³/100 g, while the sourdough-only V11 was 360 cm³/100 g. For wholemeal flour, V9 and V10 were 300 and 295 cm³/100 g, compared with 308 cm³/100 g for sourdough-only V12. The ingredient percentages and water levels also differ modestly across these formulations (Table 3), so differences should be attributed to the complete recipes and process, not to a presumed biochemical interaction between sourdough and premix. Research comparing dried and liquid sourdough preparations similarly shows that their effects depend on the material and processing method [18].

3.3. Sensory Observations

The nine-person trained panel described crust colour intensity of 2.39–2.73 in white-flour breads and approximately 3.50–3.89 in wholemeal breads. Average intensities for metallic and astringent attributes were low in the available summary, while several sourdough formulations received higher baked-aroma scores. These descriptive measurements do not constitute a consumer preference test.

3.4. Micronutrient Concentrations in Finished Bread

Table 6 reports zinc, selenium and vitamins D and E in finished bread on a common 100 g product-mass basis. In white bread without sourdough, V2 and V3 contained 0.463 and 0.503 mg Zn/100 g compared with 0.155 mg/100 g for V1; the corresponding selenium values were 4.962 and 4.870 versus 0.369 µg/100 g. In wholemeal bread without sourdough, V7 and V8 contained 0.562 and 0.611 mg Zn/100 g compared with 0.184 mg/100 g for V6. Vitamin D was 4.10 µg/100 g in V2 and 8.30 µg/100 g in V3, whereas vitamin E was 3.39 and 2.01 mg/100 g, respectively. These comparisons refer to measured concentrations in the finished products and do not estimate baking retention.

Zinc and selenium are expressed per 100 g of bread for comparison with the vitamin results and other food composition measures. The four analytes are reported in their respective mass units. The product specifications describe masses of premix ingredients, including mineral salts and vitamin preparations; these preparation masses should not be interpreted as amounts of elemental minerals or active vitamins in the bread. Accordingly, no theoretical micronutrient recovery or nutrient loss during baking is inferred from the specification.

Figure 2. Zinc and selenium concentrations per 100 g of bread across the 12 formulations. Bars show reported summary values without error bars. Hatched bars indicate formulations containing dried sourdough.

Figure 2. Zinc and selenium concentrations per 100 g of bread across the 12 formulations. Bars show reported summary values without error bars. Hatched bars indicate formulations containing dried sourdough.

The results describe finished-bread concentrations and formulation-level differences. These comparisons cannot isolate the effects of individual premix components. The complete micronutrient contents of ingredient lots, active-vitamin potency of the premixes and analyte concentrations before baking are not available for a retention calculation. Consequently, no conclusions are drawn about nutritional bioavailability or dietary efficacy.

4. Conclusions

Premix 2 was associated with higher farinograph stability and FQN in both flours, while water absorption changed in different directions. Premix-only loaves had slightly lower tabulated volume than their flour-specific controls. The premix breads had higher reported concentrations of zinc, selenium and vitamins D and E than the respective plain controls. These results describe complete formulations, without isolating the effects of individual ingredients.

The summary measurements of 12 formulations support descriptive comparisons of dough mixing, bread quality and final-product micronutrient concentrations. The available data do not support claims of statistical significance, baking retention, nutrient bioavailability or prevention of deficiency.