Antioxidant activities of chicken bone peptide fractions and their Maillard reaction products: Effects of different molecular weight distributions

Figures & data

Table 1. Free amino group in CBPH and its peptide fractions before and after the Maillard reaction with galactose.

Sample	Free amino group content (mmol/L)		Loss of free amino group (%)	pH
	Control	MRP		Control	MRP
CBPH	142.79 ± 3.18^Aa	108.68 ± 2.13^Ba	23.85 ± 2.68	6.83 ± 0.00^Aa	6.20 ± 0.02^Ba
CBPH-I	148.90 ± 2.02^Aa	108.98 ± 2.22^Ba	26.81 ± 1.18	6.86 ± 0.01^Aa	6.19 ± 0.03^Ba
CBPH-II	96.34 ± 2.45^Ab	75.44 ± 2.13^Bb	21.70 ± 0.37	6.91 ± 0.00^Aa	6.33 ± 0.02^Ba

*Control: CBPH (or CBPH-I, CBPH-II)–galactose solution without heating.

MRP: CBPH (or CBPH-I, CBPH-II)–galactose solution after heating at 100°C for 90 min without pH control.

^A–BDifferent uppercase letters in the same line indicate significant differences between the control and the MRP solution (p < 0.05).

^a–bDifferent lowercase letters in the same column indicate significant differences (p < 0.05).

Table 2. Browning and UV absorbance in CBPH and its peptide fractions before and after the Maillard reaction with galactose.

	A420nm			A294nm
Sample	Control	MRP	∆A420nm	Control	MRP	∆A294nm
CBPH	0.43 ± 0.03^Bb	0.63 ± 0.03^Ab	0.2	11.01 ± 0.00^Bb	16.28 ± 0.02^Aa	5.27
CBPH-I	0.41 ± 0.02^Bb	0.66 ± 0.00^Aa,b	0.25	9.34 ± 0.01^Bc	14.87 ± 0.04^Ab	5.52
CBPH-II	0.57 ± 0.06^Ba	0.68 ± 0.00^Aa	0.11	12.21 ± 0.01^Ba	14.99 ± 0.01^Ab	2.78

* Control: CBPH (or CBPH-I, CBPH-II)–galactose solution without heating.

MRP: CBPH (or CBPH-I, CBPH-II)–galactose solution after heating at 100°C for 90

min without pH control.

^A–BDifferent uppercase letters in the same line indicate significant differences between the control and the MRP solution (p < 0.05).

^a–bDifferent lowercase letters in the same column indicate significant differences (p < 0.05).

Figure 1. Fluorescence emission spectra of CBPH and its fractions before and after the Maillard reaction with galactose. Excitation wavelength was 347 nm. CBPH (or CBPH-I, CBPH-II) is the CBPH (or CBPH-I, CBPH-II)–galactose system without heating (i.e. the control solution). MRP is the CBPH (or CBPH-I, CBPH-II)–galactose system after heating at 100°C for 90 min without pH control (i.e. MRP solution). The control and MRP solutions were diluted fivefold with distilled water.

Figure 2. DPPH radical scavenging activities of CBPH and its fractions before and after the Maillard reaction with galactose. CBPH (or CBPH-I, CBPH-II) is the lyophilized sample from CBPH (or CBPH-I, CBPH-II)–galactose system without heating. CBPH MRP (or CBPH-I MRP, CBPH-II MRP) is the lyophilized sample from CBPH (or CBPH-I, CBPH-II)–galactose system after heating at 100°C for 90 min without pH control.

Figure 3. Hydroxyl radical scavenging activity of CBPH and its fractions before and after the Maillard reaction with galactose. CBPH (or CBPH-I, CBPH-II) is the lyophilized sample from CBPH (or CBPH-I, CBPH-II)–galactose system without heating. CBPH MRP (or CBPH-I MRP, CBPH-II MRP) is the lyophilized sample from CBPH (or CBPH-I, CBPH-II)–galactose system after heating at 100°C for 90 min without pH control.

Figure 4. Reducing power of CBPH and its fractions before and after the Maillard reaction with galactose. CBPH/CBPH-I/CBPH-II is the lyophilized sample from the CBPH/CBPH-I/CBPH-II–galactose system without heating. CBPH (or CBPH-I, CBPH-II) is the lyophilized sample from the CBPH (or CBPH-I, CBPH-II)–galactose system without heating. CBPH MRP (or CBPH-I MRP, CBPH-II MRP) is the lyophilized sample from the CBPH (or CBPH-I, CBPH-II)–galactose system after heating at 100°C for 90 min without pH control.