The study investigated the effect of supplementation of the leaf powders of
In Nigeria, one of the notably consumed staple foods with no need of introduction is bread. It is consumed widely across all age groups [
With the increasing menace of degenerative diseases [
Wheat flour, sugar, salt, yeast, and margarine were procured from Obafemi Awolowo University Central Market. Fresh fluted pumpkin, amaranth, and African eggplant were obtained from the Teaching and Research Farm of Obafemi Awolowo University, Nigeria.
Fresh vegetables (fluted pumpkin, amaranths, and African eggplant) were individually sorted, washed, destalked, and cut thinly. Each of the varietal vegetables was sliced and dried using a cabinet dryer at 55°C for 8 hrs. The dried leaves were milled to fine powder using a clean Marlex Excella (Marlex Appliances PVT, Daman, India) blender. The powders were packaged, labelled, and stored in different Ziploc® pouches for further usage.
Wheat flour was individually mixed with each of the vegetables (
Formulation of wheat-vegetable dough.
Mixture | Wheat flour (g) | Vegetable powder (g) | Yeast (g) | Margarine (g) | Sugar (g) | Salt (g) | Water (mL) |
---|---|---|---|---|---|---|---|
|
100 | 0 | 1.5 | 5 | 10 | 1 | 60 |
|
99 | 1 | 1.5 | 5 | 10 | 1 | 60 |
|
98 | 2 | 1.5 | 5 | 10 | 1 | 60 |
|
97 | 3 | 1.5 | 5 | 10 | 1 | 60 |
Wheat-vegetable dough was kneaded, scaled, cut, moulded, and placed in properly greased baking pans following the modified conditions for bread baking by Famuwagun et al. [
The protein, moisture, fibre, fat, ash, and carbohydrate of the vegetable enriched bread samples and 100% wheat bread were determined using AOAC methods [
Bread sample (5 g) was ashed, and the mineral contents (magnesium, iron, sodium, zinc, and calcium) were determined using Atomic Absorption Spectrophotometer.
A suspension of 1 g of the bread sample was made in 10 ml of distilled water. The suspension was stirred for 1 h on a magnetic stirrer. The mixture was then filtered with Whatman number 1 filter paper. The residue was discarded while the supernatant was used for antioxidant assays [
The ability to scavenge DPPH radical was determined using the method described by Pownall et al. [
This was determined using the method described by Singh and Rajini [
This was evaluated using the method of Benzie and Strain [
The total antioxidant capacity (TAC) of the bread samples was evaluated using the method of Prieto et al. [
The physical properties (volume, weight, and specific volume) of bread loaves produced were determined using the method of Khalil et al. [
The vegetable bread samples were differently coded and presented to twenty randomly selected judges for evaluation of taste, colour, flavour, texture, appearance, and overall acceptance using a nine-point hedonic scale, where 1 to 9 represented dislike extremely and like extremely, respectively. Bread produced from 100% wheat flour served as the control sample.
Data obtained from the chemical analyses and sensory evaluation were subjected to analysis of variance and means were separated using Duncan’s Multiple Range Test at 95% confidence level [
The proximate composition of the vegetable (fluted pumpkin, African eggplant, and amaranth) enriched breads is presented in Table
Proximate composition (%) of wheat bread enriched with green leafy vegetable powders.
Bread sample | Moisture | Fat | Fibre | Ash | Protein | Carbohydrate |
---|---|---|---|---|---|---|
99% WF: 1% TOL | 24.5 ± 0.02 |
1.3 ± 0.03 |
2.0 ± 0.02 |
1.1 ± 0.02 |
10.9 ± 0.10 |
60.2 ± 0.01 |
98% WF: 2% TOL | 23.4 ± 0.05 |
1.4 ± 0.02 |
2.8 ± 0.02 |
1.7 ± 0.01 |
11.2 ± 0.02 |
59.6 ± 0.02 |
97% WF: 3% TOL | 22.6 ± 0.02 |
1.4 ± 0.04 |
4.0 ± 0.03 |
2.2 ± 0.02 |
13.9 ± 0.02 |
55.9 ± 0.02 |
99% WF: 1% AVL | 25.1 ± 0.01 |
1.3 ± 0.01 |
1.9 ± 0.02 |
1.1 ± 0.01 |
10.5 ± 0.02 |
60.1 ± 0.01 |
98% WF: 2% AVL | 23.8 ± 0.02 |
1.3 ± 0.02 |
2.2 ± 0.01 |
1.9 ± 0.02 |
11.0 ± 0.02 |
59.9 ± 0.01 |
97% WF: 3% AVL | 21.9 ± 0.01 |
1.4 ± 0.02 |
3.1 ± 0.01 |
2.4 ± 0.01 |
12.4 ± 0.01 |
58.8 ± 0.02 |
99% WF: 1% SML | 25.9 ± 0.02 |
1.4 ± 0.01 |
1.9 ± 0.02 |
1.1 ± 0.02 |
9.8 ± 0.02 |
59.9 ± 0.01 |
98% WF: 2% SML | 24.9 ± 0.03 |
1.7 ± 0.05 |
2.4 ± 0.02 |
1.5 ± 0.01 |
10.1 ± 0.02 |
59.3 ± 0.01 |
97% WF: 3% SML | 22.5 ± 0.02 |
2.0 ± 0.03 |
3.5 ± 0.01 |
2.0 ± 0.02 |
10.8 ± 0.01 |
59.2 ± 0.01 |
100% WF | 26.9 ± 0.03 |
1.3 ± 0.01 |
1.8 ± 0.02 |
1.1 ± 0.02 |
9.5 ± 0.02 |
59.9 ± 0.01 |
Mean values along the same column with different superscripts are significantly different
The moisture content of the enriched bread significantly
The bread samples enriched with African eggplant were observed to have the highest moisture content across all the entire vegetable group. Thus, the enriched bread group that was closest to the 100% wheat bread in terms of moisture was the bread enriched with the African eggplant
The moisture contents of the vegetable enriched bread (21.9 to 25.9%) were close to the moisture content of 29.6% reported for green tea fortified bread [
As presented in Table
The observed protein contents (9.8 to 13.9%) of the vegetable enriched breads at 1 to 3% enrichment level in this study were within the reported range of the protein content (10.6 to 18.0%) of bread enriched with 5 to 20% tilapia fish flour by Adeleke and Odedeji [
Significant (
Increase was obtained (1.3 to 2.0%) for the fat content of the vegetable enriched bread samples as presented in Table
The crude fibre content (1.8 to 4.0%) of the bread samples also increased significantly (
As presented in Table
The mineral composition for the bread samples is presented in Table
Mineral nutrients (mg/100 g) of wheat bread fortified with green leafy vegetable powders.
Bread sample | Magnesium | Iron | Sodium | Zinc | Calcium |
---|---|---|---|---|---|
99% WF: 1% TOL | 172.5 ± 0.05 |
48.6 ± 0.01 |
18.2 ± 0.02 |
10.0 ± 0.22 |
259.0 ± 0.30 |
98% WF: 2% TOL | 176.0 ± 0.02 |
49.1 ± 0.02 |
21.8 ± 0.05 |
11.5 ± 1.50 |
280.0 ± 0.25 |
97% WF: 3% TOL | 179.0 ± 0.02 |
53.7 ± 0.02 |
22.7 ± 0.07 |
13.4 ± 0.15 |
306.0 ± 0.30 |
99% WF: 1% AVL | 167.2 ± 0.01 |
35.1 ± 0.03 |
22.3 ± 0.09 |
7.8 ± 0.02 |
250.0 ± 0.30 |
98% WF: 2% AVL | 170.5 ± 0.03 |
38.5 ± 0.02 |
25.5 ± 0.08 |
9.6 ± 0.55 |
262.0 ± 0.05 |
97% WF: 3% AVL | 174.5 ± 0.03 |
39.6 ± 0.01 |
27.1 ± 0.03 |
10.2 ± 0.81 |
307.5 ± 0.45 |
99% WF: 1% SML | 157.5 ± 0.04 |
42.6 ± 0.04 |
19.9 ± 0.21 |
9.8 ± 0.11 |
261.0 ± 0.15 |
98% WF: 2% SML | 161.0 ± 0.02 |
48.2 ± 0.02 |
21.0 ± 0.03 |
10.7 ± 0.45 |
310.3 ± 0.15 |
97% WF: 3% SML | 162.0 ± 0.01 |
54.2 ± 0.02 |
23.3 ± 0.01 |
14.0 ± 0.15 |
330.5 ± 0.25 |
100% WF | 155.5 ± 0.02 |
33.5 ± 0.02 |
15.9 ± 0.02 |
6.7 ± 0.02 |
248.5 ± 0.40 |
Mean values along the same column with different superscripts are significantly different
The antioxidant properties of the bread samples are presented in Table
Antioxidant properties of wheat bread fortified with green leafy vegetable powders.
Bread sample | TPC |
DPPH |
MCA |
FRAP |
TAC |
---|---|---|---|---|---|
99% WF: 1% TOL | 92.1 ± 0.03 |
38.8 ± 0.01 |
44.0 ± 0.01 |
128.8 ± 0.05 |
14.1 ± 0.01 |
98% WF: 2% TOL | 93.8 ± 0.02 |
40.9 ± 0.02 |
50.7 ± 0.01 |
129.6 ± 0.01 |
14.1 ± 0.01 |
97% WF: 3% TOL | 106.0 ± 0.01 |
45.3 ± 0.01 |
52.8 ± 0.02 |
134.0 ± 0.02 |
28.1 ± 0.02 |
99% WF: 1% AVL | 87.1 ± 0.02 |
35.0 ± 0.02 |
42.6 ± 0.04 |
127.8 ± 0.01 |
12.1 ± 0.06 |
98% WF: 2% AVL | 90.3 ± 0.04 |
40.1 ± 0.01 |
46.8 ± 0.01 |
129.6 ± 0.01 |
14.1 ± 0.08 |
97% WF: 3% AVL | 105.9 ± 0.01 |
38.7 ± 0.01 |
48.9 ± 0.01 |
131.2 ± 0.01 |
14.9 ± 0.04 |
99% WF: 1% SML | 87.1 ± 0.02 |
43.0 ± 0.01 |
42.4 ± 0.02 |
128.0 ± 0.01 |
14.2 ± 0.06 |
98% WF: 2% SML | 92.5 ± 0.02 |
44.7 ± 0.01 |
42.8 ± 0.04 |
129.9 ± 0.02 |
14.9 ± 0.02 |
97% WF: 3% SML | 105.0 ± 0.01 |
52.0 ± 0.01 |
47.3 ± 0.01 |
133.0 ± 0.01 |
19.2 ± 0.03 |
100% WF | 85.5 ± 0.02 |
38.5 ± 0.02 |
41.5 ± 0.01 |
126.7 ± 0.01 |
12.4 ± 0.01 |
Mean values along the same column with different superscripts are significantly different
The physical properties of the bread samples are presented on Table
Physical properties of wheat bread fortified with green leafy vegetable powders.
Bread sample | Weight (g) | Volume (cm3) | Specific volume (cm3/g) |
---|---|---|---|
99% WF: 1% TOL | 138.3 ± 0.03 |
572.2 ± 0.01 |
4.1 ± 0.02 |
98% WF: 2% TOL | 146.4 ± 0.02 |
567.9 ± 0.02 |
3.9 ± 0.04 |
97% WF: 3% TOL | 154.2 ± 0.02 |
552.1 ± 0.01 |
3.6 ± 0.02 |
99% WF: 1% AVL | 136.8 ± 0.04 |
573.6 ± 0.05 |
4.2 ± 0.02 |
98% WF: 2% AVL | 142.5 ± 0.02 |
569.4 ± 0.02 |
4.0 ± 0.03 |
97% WF: 3% AVL | 147.0 ± 0.03 |
555.7 ± 0.01 |
3.8 ± 0.02 |
99% WF: 1% SML | 136.4 ± 0.01 |
573.1 ± 0.03 |
4.2 ± 0.02 |
98% WF: 2% SML | 138.2 ± 0.01 |
563.0 ± 0.02 |
4.1 ± 0.02 |
97% WF: 3% SML | 146.6 ± 0.02 |
553.0 ± 0.01 |
3.8 ± 0.02 |
100% WF | 134.4 ± 0.01 |
579.5 ± 0.02 |
4.3 ± 0.02 |
Mean values along the same column with different superscripts are significantly different
Results of the sensory evaluation (Table
Sensory properties of wheat bread fortified with green leafy vegetable powders.
Sample | Taste | Colour | Flavour | Texture | Appearance | Overall acceptability |
---|---|---|---|---|---|---|
99% WF: 1% TOL | 7.5 ± 0.45 |
8.0 ± 0.12 |
6.0 ± 0.14 |
7.3 ± 0.04 |
7.2 ± 0.16 |
7.9 ± 0.05 |
98% WF: 2% TOL | 6.4 ± 0.05 |
7.7 ± 0.14 |
5.5 ± 0.07 |
6.9 ± 0.04 |
6.7 ± 0.05 |
7.2 ± 0.06 |
97% WF: 3% TOL | 6.2 ± 0.11 |
5.0 ± 0.10 |
5.0 ± 0.08 |
6.1 ± 0.05 |
5.0 ± 0.08 |
4.0 ± 0.04 |
99% WF: 1% AVL | 7.7 ± 0.08 |
6.2 ± 0.19 |
5.9 ± 0.02 |
7.0 ± 0.13 |
7.0 ± 0.03 |
6.5 ± 0.06 |
98% WF: 2% AVL | 6.9 ± 0.09 |
5.5 ± 0.12 |
5.4 ± 0.04 |
6.3 ± 0.10 |
6.2 ± 0.06 |
5.9 ± 0.06 |
97% WF: 3% AVL | 5.9 ± 0.31 |
4.9 ± 0.45 |
5.2 ± 0.09 |
6.0 ± 0.04 |
4.8 ± 0.05 |
4.4 ± 0.05 |
99% WF: 1% SML | 7.2 ± 0.21 |
6.2 ± 0.37 |
6.2 ± 0.03 |
7.0 ± 0.04 |
6.6 ± 0.03 |
6.1 ± 0.06 |
98% WF: 2% SML | 6.9 ± 0.12 |
5.4 ± 0.12 |
5.4 ± 0.05 |
6.7 ± 0.10 |
5.3 ± 0.05 |
6.0 ± 0.05 |
97% WF: 3% SML | 5.1 ± 0.22 |
4.8 ± 0.25 |
4.9 ± 0.14 |
6.1 ± 0.04 |
4.9 ± 0.04 |
5.0 ± 0.07 |
100% WF | 8.2 ± 0.12 |
8.5 ± 0.21 |
7.0 ± 0.31 |
7.5 ± 0.07 |
8.5 ± 0.07 |
8.7 ± 0.04 |
Mean values along the same column with different superscripts are significantly different
The enrichment of bread with either fluted pumpkin, African eggplant, or amaranth resulted in increase in proximate, mineral, and antioxidant contents of the enriched bread. Bread enriched with vegetables was acceptable at low inclusion levels (1-2%) by consumers that are fit to eat bread no matter the age group. The acceptability of bread samples with higher inclusion level(s) would only be possible with a lot of awareness creation about the health potentials. This work emphasized the possibility of enriching bread with green leafy vegetables highlighted.
The authors declare that there are no conflicts of interest regarding the publication of this research work.
This research was supported by International Development Research Centre and the Department of Foreign Affairs, Trade and Development/Canadian International Food Security Research Fund through Project 107983 on synergizing indigenous vegetables and fertilizer micro-dosing innovations among West African farmers.