Introduction
Materials and methods
Source of wild lettuce powder
Experimental sample preparations
Preparation of African wild lettuce leaf powder sample
Preparation of wild lettuce leaf ethanolic extracts and residue
Preparation of wild lettuce leaf protein isolate
Determination of chemical composition of wild lettuce leaf samples
Protein quality indices of African wild lettuce powder samples
Phytochemicals composition of African wild lettuce leaf samples
Antioxidant activity of African wild lettuce leaf powder samples
Ferric reducing antioxidant power (FRAP) assay
2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity assay
Ferrous ion-chelating activity
2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS)
Hydroxyl (OH) free radicals scavenging activity
Determination of angiotensin converting enzyme (ACE) inhibition activity of African wild lettuce leaf samples
Alpha-amylase inhibition assay of African wild lettuce leaf powder samples
Alpha-glucosidase inhibition assay of African wild lettuce leaf powder samples
Statistical analysis
Results
Nutrient composition of wild lettuce leaf powder samples
Component | WLF | WLE | WLR | WPI |
---|---|---|---|---|
Protein | 23.28 ± 0.04cb | 24.17 ± 0.02b | 7.89 ± 0.02d | 46.57 ± 0.08a |
Fiber | 17.31 ± 2.02b | 10.59 ± 0.96c | 37.37 ± 2.98a | 4.17 ± 0.02d |
Fat | 3.95 ± 0.08a | 3.64 ± 0.36a | 3.97 ± 0.04a | 1.95 ± 0.57b |
Ash | 14.05 ± 0.56b | 10.03 ± 0.47c | 15.26 ± 0.51a | 9.41 ± 0.52d |
Moisture | 4.44 ± 0.55b | 6.03 ± 0.55a | 7.05 ± 0.55a | 4.15 ± 0.52b |
Carbohydrate | 37.07 ± 3.15a | 45.94 ± 4.08a | 46.45 ± 2.19a | 34.07 ± 3.17a |
Element or ratio | WLF | WLE | WLR | WPI |
---|---|---|---|---|
Cu | 0.01 ± 0.00b | 0.01 ± 0.00a | 0.01 ± 0.00a | 0.01 ± 0.00a |
Fe | 0.47 ± 0.02d | 0.51 ± 0.02b | 0.63 ± 0.00a | 0.49 ± 0.03c |
Zn | 0.06 ± 0.00c | 0.08 ± 0.01a | 0.06 ± 0.01c | 0.07 ± 0.01b |
Mn | 1.35 ± 0.03d | 2.01 ± 0.02a | 1.92 ± 0.02b | 1.72 ± 0.02c |
K | 8.93 ± 0.22b | 11.99 ± 0.32c | 13.09 ± 2.02d | 6.61 ± 0.12a |
Na | 5.36 ± 0.11b | 7.56 ± 0.11a | 7.78 ± 0.02a | 4.04 ± 0.03b |
Mg | 0.74 ± 0.03d | 2.54 ± 0.12b | 3.10 ± 0.11a | 1.86 ± 0.11c |
Ca | 1.61 ± 0.04c | 6.15 ± 0.32b | 6.31 ± 0.03a | 1.22 ± 0.03d |
P | 13.91 ± 0.02b | 10.60 ± 1.02c | 15.43 ± 3.23a | 9.27 ± 0.33d |
Ca/P | 0.12 ± 0.11a | 0.58 ± 0.03a | 0.41 ± 0.02a | 0.13 ± 0.03a |
Na/K | 0.6 ± 0.01a | 0.63 ± 0.02a | 0.59 ± 0.03a | 0.61 ± 0.01a |
Zn/Cu | 6.0 ± 0.03c | 8.0 ± 1.16a | 6.0 ± 0.02c | 7.0 ± 0.02b |
Amino acid | WLF | WLR | WLE | WPI | Adult | Children |
---|---|---|---|---|---|---|
Methionine | 1.53 ± 0.01d | 1.89 ± 0.23b | 1.65 ± 0.01c | 12.88 ± 1.02a | 1.5 | 2.7 |
Valine | 6.96 ± 0.21a | 6.45 ± 0.22b | 6.93 ± 0.33a | 6.07 ± 0.21c | 2.6 | 3.8 |
Phenylalanine | 5.38 ± 0.13c | 5.57 ± 0.02b | 4.89 ± 0.14d | 5.79 ± 0.33a | 2.5 | 6.9 |
Isoleucine | 4.53 ± 0.01c | 4.87 ± 0.41b | 4.87 ± 0.11b | 5.29 ± 0.03a | 2.5 | 6.9 |
Leucine | 5.93 ± 0.02a | 7.68 ± 0.05a | 6.53 ± 0.02a | 7.85 ± 0.11a | – | 1.0 |
Threonine | 4.74 ± 0.22b | 3.94 ± 0.03d | 4.86 ± 0.05a | 4.17 ± 0.03c | 3.9 | 7.3 |
Histidine | 1.97 ± 0.00b | 1.6 ± 0.11c | 5.69 ± 0.13a | 1.46 ± 0.00d | – | 1.0 |
Tryptophan | 6.11 ± 1.11a | 6.09 ± 0.42a | 4.16 ± 0.01c | 5.60 ± 0.01b | 1.5 | 3.7 |
Lysine | 6.45 ± 0.31b | 3.34 ± 0.02c | 7.06 ± 0.00a | 3.0 ± 0.02d | 0.4 | 1.25 |
ƩEAAs | 41.63 ± 4.12b | 39.83 ± 2.02d | 40.95 ± 5.02c | 50.65 ± 3.22a | 3.4 | 6.4 |
Non-Essential amino Acids | ||||||
Glycine | 6.48 ± 0.22a | 6.14 ± 0.03b | 5.77 ± 0.11c | 4.25 ± 0.12d | – | – |
Alanine | 6.70 ± 0.00b | 4.71 ± 0.22d | 5.78 ± 0.02c | 6.74 ± 0.13a | – | – |
Serine | 4.48 ± 0.04c | 5.33 ± 0.00a | 4.29 ± 0.03d | 4.95 ± 0.02b | – | – |
Proline | 6.40 ± 0.01b | 6.09 ± 0.21c | 6.72 ± 0.33a | 5.22 ± 0.00d | – | – |
Arginine | 6.33 ± 0.032b | 5.27 ± 0.02d | 6.62 ± 0.04a | 5.86 ± 0.03c | – | – |
Tyrosine | 1.97 ± 0.04c | 4.88 ± 0.03b | 1.39 ± 0.01d | 5.29 ± 0.21a | – | – |
Cystine | 1.36 ± 0.00b | 1.39 ± 0.22b | 1.04 ± 0.01c | 1.67 ± 0.22a | – | – |
Aspartate | 9.09 ± 0.11b | 6.99 ± 0.42c | 9.54 ± 0.03a | 6.24 ± 0.04d | – | – |
Glutamate | 12.65 ± 0.32c | 13.08 ± 0.05a | 12.94 ± 1.02b | 2.15 ± 0.01d | – | – |
ƩNEAAs | 57.43 ± 4.42b | 58.76 ± 2.03a | 55.48 ± 4.02c | 47.66 ± 3.03d | – | – |
Protein Quality Indices | ||||||
TAA | 99.06 ± 6.02a | 98.59 ± 3.02b | 96.43 ± 4.02c | 98.31 ± 2.02b | ||
TEAA/TNEAA | 0.72 ± 0.00b | 0.68 ± 0.22c | 0.73 ± 0.12b | 1.06 ± 0.02a | – | |
ƩSAA (meth+cys) | 2.89 ± 0.01c | 3.28 ± 0.11b | 2.69 ± 0.02d | 14.55 ± 0.12a | – | |
ƩArAA (phy + tyr) | 7.35 ± 0.23c | 10.45 ± 2.11b | 6.28 ± 0.32d | 11.08 ± 0.52a | – | |
Arg/Lys | 0.98 ± 0.02c | 1.58 ± 0.03b | 0.94 ± 0.11d | 1.95 ± 0.02a | – | |
BCCAs | 17.42 ± 3.02c | 19.00 ± 1.22a | 18.33 ± 2.02b | 19.21 ± 2.02a | – | |
BV (%) | 77.04 | 72.26 | 85.75 | 88.97 | 70 | |
PER (g/100 g) | 3.00 | 2.79 | 3.21 | 3.51 | – | |
EAAI (%) | 81.41 | 77.03 | 89.40 | 92.36 | – |
Sample | WLF | WLE | WLR | WPI |
---|---|---|---|---|
Saponin | 199.09 ± 1.29a | 68.18 ± 1.29c | 150.00 ± 1.29b | 59.09 ± 1.29d |
Tannin | 57.37 ± 4.27a | 5.43 ± 0.85c | 27.17 ± 0.00b | 4.23 ± 0.85c |
Oxalate | 24.45 ± 0.19d | 11.03 ± 0.32b | 20.84 ± 0.91c | 7.20 ± 0.11a |
Flavonoid | 4.48 ± 0.19b | 0.42 ± 0.00d | 2.77 ± 0.32c | 13.43 ± 0.19a |
Phytate | 19.86 ± 0.19a | 14.914 ± 0.12b | 15.74 ± 0.12b | 11.95 ± 0.58c |
Terpenoids | 70.21 ± 1.13a | 58.38 ± 0.56b | 67.15 ± 0.94a | 51.86 ± 1.88c |
Phenol | 19.47 ± 0.04c | 27.08 ± 0.04b | 15.33 ± 0.08d | 28.89 ± 0.04a |
Phytate/mineral (Ca, Zn and Fe) molar ratios | ||||
Phytate/calcium | 0.75 | 0.15 | 0.15 | 0.59 |
Phytate/zinc | 34.93 | 17.49 | 27.68 | 16.35 |
Phytate/iron | 3.59 | 2.48 | 2.11 | 2.04 |
Phytate/Ca & Zn | 1.40 | 2.69 | 4.37 | 0.50 |
Antioxidant activities of African wild lettuce powder samples
Sample | WLF | WLE | WLR | WPI |
---|---|---|---|---|
Fe Chelation% | 8.26 ± 0.09c | 34.43 ± 0.09b | 5.84 ± 0.09c | 36.64 ± 0.19a |
DPPH% | 18.28 ± 0.04d | 70.85 ± 0.04b | 53.07 ± 0.04c | 91.88 ± 0.04a |
ABTS mg/g | 205.36 ± 12.63b | 339.29 ± 25.21a | 169.64 ± 12.62b | 383.92 ± 12.62a |
FRAPS mg/g | 47.46 ± 0.021c | 49.92 ± 0.04b | 44.17 ± 0.02d | 50.33 ± 0.02a |
OH % | 74.00 ± 7.68ab | 60.00 ± 6.46b | 74.57 ± 7.67ab | 80.29 ± 2.82a |