Structure, physicochemical, and functional properties of protein isolates and major fractions from cumin (Cuminum cyminum) seeds

Figures & data

Figure 1. SDS-PAGE patterns of CPI and cumin protein fractions. M, marker standard; A, under non-reducing condition (without β-mercaptoethanol) for CPI (lane 1), albumin (lane 2), globulin (lane 3), and glutelin (lane 4); B, under reducing condition (with β-mercaptoethanol) for CPI (lane 5), albumin (lane 6), globulin (lane 7), and glutelin (lane 8).

Table 1. Amino acid compositions of cumin protein isolate (CPI) and cumin protein fractions (g/100g protein).

Amino acid	CPI	Albumin	Globulin	Glutelin	FAO/WHO^g
					Child	Adult
Aspartic acid/Asp	10.74	10.99	10.65	8.86
Threonine/Thr	3.52	3.30	3.87	3.02	3.40	0.90
Serine/Ser	3.97	3.66	4.17	3.56
Glutamic acid/Glu	18.98	20.51	17.67	15.99
Glycine/Gly	4.90	4.37	4.77	5.37
Alanine/Ala	4.20	3.86	4.60	3.61
Cystine/Cys	0.99	0.74	0.55	0.56
Valine/Val	4.92	4.55	5.60	4.66	3.50	1.30
Methionine/Met	1.90	1.08	1.97	1.19
Isoleucine/Ile	5.05	4.73	4.91	3.61	2.80	1.30
Leucine/Leu	6.80	6.06	6.90	4.95	6.60	1.90
Tyrosine/Tyr	2.24	1.33	2.63	2.99
Phenylalanine/Phe	6.09	6.82	6.06	4.00
Lysine/Lys	4.26	4.13	3.90	3.30	5.80	1.60
Histidine/His	2.63	2.25	2.43	2.26	1.90	1.60
Arginine/Arg	8.35	8.22	7.91	4.71
Proline/Pro	4.00	3.92	3.74	3.20
Tryptophan/Trp	-	-	-	-	1.10	0.50
Essential amino acid	35.16	32.91	35.65	26.98
Non-essential amino acid	58.36	57.60	56.67	48.84
Acidic amino acid^b	29.71	31.50	28.31	24.85
Basic amino acid^c	15.24	14.60	14.24	10.27
Aromatic amino acid^f	8.33	8.15	8.69	6.99	6.30	1.90
Sulphur amino acid^e	2.88	1.82	2.52	1.75	2.50	1.70
Hydrophobic amino acid	32.95	31.01	33.78	25.20
EAA/TAA	37.60	36.36	38.61	35.58
EAA/NEAA	60.25	57.14	62.90	55.24

a, Essential amino acids.

b, Acidic amino acid: Asp, Glu;

c, Basic amino acid: Lys, Arg, His;

d, Hydrophobic amino acid: Ala, Ile, Leu, Met, Phe, Pro, Val;

e, Sulphur amino acid: Met, Cys;

f, Aromatic amino acid: Tyr, Phe;

g, Essential amino acid requirement by FAO/WHO for a 2–5-year-old child or adult.

Figure 2. Far-UV CD (190–240 nm) spectra (A) and intrinsic fluorescence spectra (B) of CPI, albumin, and glutelin in 10 mM phosphate buffer (pH 7.0) at a concentration of 0.1 mg/mL.

Figure 3. 3D-view and typical top-view AFM images of CPI (A and B), albumin (C and D), and glutelin (E and F). Scan area was 5 μm×5 μm.

Table 2. H_o, ζ, D_h, EAI, and ESI of CPI, albumin, and glutelin and d_4,3 of their emulsions at a protein concentration of 0.1% (w/v).

	Ho	ζ (mV)	Dh (nm)	EAI (m^2/g)	ESI (min)	d4,3 (μm)
CPI	343.35 ± 22.74 ^b	−20.33 ± 0.40 ^a	122.12 ± 1.16 ^b	69.43 ± 2.29 ^b	21.51 ± 0.86 ^b	26.51 ± 0.14 ^a
Albumin	327.42 ± 3.47 ^bc	−14.50 ± 0.01 ^b	107.80 ± 1.62 ^c	103.67 ± 4.49 ^a	42.84 ± 4.16 ^a	4.29 ± 0.26 ^c
Glutelin	924.56 ± 12.83 ^a	−21.18 ± 1.44 ^a	131.25 ± 1.43 ^a	69.37 ± 1.7 ^b	14.12 ± 0.70 ^c	18.93 ± 0.91 ^b

H_o, surface hydrophobicity; ζ, Zeta-potential; D_h, hydrodynamic diameter; d_4,3, volume-weighted mean diameter. Means with rows with different letters are significantly different (p < 0.05), according to Duncan’s multiple range test.

Figure 4. Protein solubility curves of CPI, albumin, and glutelin at different pH values.

Figure 5. Particle distribution (A), optical microscopy images (B) of emulsions stabilized by CPI, albumin, and glutelin at a concentration of 0.1% (w/v), and changes in storage modulus (G′) and loss modulus (G″) of 10% (w/v) CPI, albumin, and glutelin dispersion with time and temperature (C). The bar accounts for 100 μm.