Structure and functional properties of protein from defatted Camellia oleifera seed cake: Effect of hydrogen peroxide decolorization

Figures & data

Table 1. Comparison of structural properties of decolorized and nondecolorized protein

Structural properties	SCP	DSCP
Surface hydrophobicity	33.99 ± 0.76	34.68 ± 0.21*
Free sulfhydryl group	6.48 ± 0.14	4.91 ± 0.59*
Total sulfhydryl group	10.85 ± 0.03	9.25 ± 0.84*

Note: decolorized protein versus nondecolorized protein; *represents significant difference

(p < 0.05).

Figure 1. DSC analysis of DSCP and SCP

Figure 2. SDS-PAGE of SCP and DSCP (M: Marker; 1: SCP; 2: DSCP)

Table 2. Amino acid comosition of SCP (g/100g protein)

Sequence number	Name	Non-decolorized protein	Decolorized protein	WHO
				Adult
1	Aspartic acid^c	4.37	4.93
2	Threonine^a	0.44	0.91	0.9
3	Serine	1.16	1.48
4	Glutamic acid^c	23.63	22.14
5	Glycine^d	1.51	1.90
6	Alanine^d	2.17	2.62
7	Cystine^f	0.61	1.18
8	Valine^ad	2.80	2.59	1.3
9	Methionine^adf	0.78	0.88
10	Isoleucine^ad	1.12	1.65	1.3
11	Leucine^d	4.06	4.57	1.9
12	Tyrosine^e	0.13	0.26
13	Phenylalanine^ade	1.26	1.60
14	Histidine^ab	0.92	1.03	1.60
15	Lysine^ab	1.93	2.05	1.60
16	Arginine^b	8.18	8.25
17	Proline^d	1.03	1.39

Note: a: essential amino-acid; b: basic amino acid; c: acidic amino acid; d: hydrophobic amino acid, e:contains benzene ring amino acids; f: sulfur-containing amino acid.

Figure 3. IR spectra of SCP and DSCP

Figure 4. X-ray diffraction patterns of DSCP and SCP

Figure 5. Scanning results of decolorized and nondecolorized proteins detected on electron microscope (1 and2, ×100; 3 and 4, ×5000)

Figure 6. Difference in pH–solubility curve between DSCP and SCP

Table 3. Comparison of functional properties between decolorized and nondecolorized proteins

Functional properties	Nondecolorized protein	Decolorized protein
Emulsifying activity	14.48 ± 0.35	14.01 ± 0.65*
Emulsification stability	29.64 ± 1.24	29.14 ± 0.79*
Foaming capacity	38.33 ± 1.28	33.33 ± 2.43*
Foaming stability	66.67 ± 2.18	48.33 ± 1.54**
Oil holding capacity	2.26 ± 0.01	2.71 ± 0.15*
Water holding capacity	1.83 ± 0.02	2.05 ± 0.03*

Note: decolorized protein versus nondecolorized protein *represents significant difference (p< 0.05); **represents extreme significant difference (p < 0.01).