Comparative study of the structural and functional properties of protein isolates prepared from edible vegetable leaves

Figures & data

Table 1. Amino acid composition (%) of vegetable leaf protein isolates

Amino acid	Amaranth	Eggplant	Fluted pumpkin	WHO/Child	FAO Adult
Asp + Asn	10.73	11.01	10.28
Ala	6.27	6.13	6.75
Arg	6.32	5.94	6.88
Cys	1.66	2.63	1.66
Glu + Gln	12.16	12.42	11.08
Gly	5.11	5.15	5.22
Hist	3.05	3.35	3.53	1.90	1.60
Ile	4.69	4.32	4.72	2.80	1.30
Leu	8.64	7.78	9.04	6.60	1.90
Lys	7.09	6.63	6.92	5.80	1.60
Met	2.29	1.86	2.22	2.70	1.70
Phe	5.30	5.63	5.66	6.30	1.90
Pro	5.11	5.20	4.30
Ser	5.45	5.56	5.22
Thr	4.75	4.55	4.22	3.40	0.90
Trp	1.46	1.74	2.21
Tyr	4.26	4.68	4.35
Val	5.65	5.41	5.73	3.50	1.50
AAA	11.02	12.05	12.22
BCAA	18.98	17.51	19.49
HAA	45.33	45.38	46.64
PCAA	10.14	9.98	10.48
NCAA	22.89	23.43	21.36
SCAA	3.95	4.49	3.88
EAA	42.92	41.27	44.25
Arginine/Lysine	0.89	0.89	0.99

Hydrophobic amino acids (HAA) = alanine, valine, isoleucine, leucine, tyrosine, phenylalanine, tryptophan, proline, methionine and cysteine; aromatic amino acids (AAA) = phenylalanine, tryptophan and tyrosine; positively charged amino acids (PCAA) = arginine, histidine, lysine; negatively charged amino acids (NCAA) = aspartic + asparagine, glutamic + glutamine, threonine, serine; essential amino acids (EAA) = histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine; sulphur containing amino acids (SCAA) = methionine, cysteine; branched chain amino acids (BCAA) = leucine, isoleucine, valine

Figure 1. Non-reduced (a) and reduced (b) SDS-PAGE of amaranth (ALI), eggplant (ELI) and fluted pumpkin (FLI) leaf protein isolates.

Figure 2. Fluorescence intensity of amaranth (ALI), eggplant (ELI) and fluted pumpkin (FLI) leaf protein isolates.

Figure 3. Far-UV circular dichroism spectra of amaranth (ALI), eggplant (ELI) and fluted pumpkin (FLI) leaf protein isolates.

Figure 4. Near-UV circular dichroism spectra of amaranth (ALI), eggplant (ELI) and fluted pumpkin (FLI) leaf protein isolates pH-dependent solubility profiles of amaranth leaf protein isolate (ALI), eggplant leaf protein isolate (ELI) and fluted pumpkin leaf isolate (FLI).

Figure 5. Surface hydrophobicity of amaranth (ALI), eggplant (ELI) and fluted pumpkin (FLI) leaf protein isolates.

Figure 6. pH-dependent solubility profile of amaranth (ALI), eggplant (ELI) and fluted pumpkin (FLI) leaf protein isolates.

Figure 7. Effect of pH and protein concentration on oil droplet size (d_3,2) and emulsion stability (%) of amaranth (ALI), eggplant (ELI) and fluted pumpkin (FLI) leaf protein isolates.

Figure 8. Oil droplet size distributions of emulsions formed with amaranth (ALI), eggplant (ELI) and fluted pumpkin (FLI) leaf protein isolates.

Figure 9. Effect of pH and protein concentration on the foaming capacity and foam stability of amaranth (ALI), eggplant (ELI) and fluted pumpkin (FLI) leaf protein isolates.