Structural and functional properties of rice bran protein oxidized by peroxyl radicals

Figures & data

Table 1. Protein carbonyl, free sulfhydryl, total sulfhydryl, disulfide bond, and surface hydrophobicity of RBP incubated with increasing concentrations of AAPH.

AAPH (mM)	Protein carbonyl(nmol/mg)	Free sulfhydryl(nmol/mg)	Total sulfhydryl(nmol/mg)	Disulfide bonds (nmol/mg)	Surfacehydrophobicity
0	3.30 ± 0.13^a*	5.10 ± 0.18^f	8.61 ± 0.21^f	3.51 ± 0.04^e	10.58 ± 0.32^b
0.04	4.09 ± 0.13^b	4.57 ± 0.17^e	5.99 ± 0.19^e	1.42 ± 0.05^c	12.90 ± 0.31^c
0.2	4.97 ± 0.15^c	4.21 ± 0.17^d	5.56 ± 0.17^d	1.35 ± 0.04^b	16.06 ± 0.33^f
1	5.74 ± 0.12^d	3.60 ± 0.15^c	4.81 ± 0.18^c	1.21 ± 0.03^a	14.97 ± 0.43^e
5	6.60 ± 0.13^e	2.85 ± 0.16^b	4.66 ± 0.19^b	1.81 ± 0.04^d	13.84 ± 0.31^d
25	7.21 ± 0.11^f	2.07 ± 0.18^a	3.90 ± 0.18^a	1.83 ± 0.02^d	8.61 ± 0.18 ^a

*Columns with different letters are significantly different (p < 0.05).

Figure 1. Intrinsic fluorescence of native and modified RBP.

Figure 2. Effect of oxidization on the FT-IR spectra of RBP (a) and deconvolution of the amide I spectra (continuous curve), the GCF bands thereof (point line), and the second-derivative spectra of RBP (b).

Table 2. Effects of the oxidization treatment on the secondary structures of RBP.

AAPH (mM)	α-helix	Parallelβ-sheet	Antiparallelβ- sheet	β- sheet	Unorderedstructure	β-turn
0	17.42 ± 0.02^d*	27.44 ± 0.03^a	21.80 ± 0.02^e	49.24 ± 0.03^a	16.76 ± 0.01^d	16.57 ± 0.03^c
0.04	17.03 ± 0.03^a	28.18 ± 0.05^d	21.23 ± 0.01^b	49.41 ± 0.02^c	17.15 ± 0.03^e	16.41 ± 0.02^b
0.2	17.18 ± 0.01^b	28.59 ± 0.02^f	20.76 ± 0.02^a	49.35 ± 0.01^b	17.95 ± 0.02^f	15.53 ± 0.03^a
1	17.35 ± 0.04^c	28.01 ± 0.04^c	21.57 ± 0.03^d	49.58 ± 0.03^d	16.40 ± 0.05^c	16.66 ± 0.05^d
5	17.42 ± 0.03^d	28.32 ± 0.03^e	21.40 ± 0.04^c	49.72 ± 0.04^e	15.96 ± 0.03^b	16.91 ± 0.04^e
25	17.57 ± 0.02^e	27.90 ± 0.01^b	22.14 ± 0.03^f	50.04 ± 0.05^f	15.37 ± 0.04^a	17.02 ± 0.03^f

*Columns with different letters are significantly different (p < 0.05).

Figure 3. SDS-PAGE profiles of native and oxidized RBP.

Figure 4. Solubility, EAI, and ESI of native and oxidized RBP.