Figures & data
Figure 1. Effect of ferrous ion concentration and oxidation duration on the formation of malondialdehyde in Fe2+-vitamin C-induced linoleic acid oxidation model. (a) Ferrous ion concentration and (b) oxidation duration. Data are the mean ± standard deviation of triplicate tests. Different letters represent significant difference in the means at a significant level of 0.05
![Figure 1. Effect of ferrous ion concentration and oxidation duration on the formation of malondialdehyde in Fe2+-vitamin C-induced linoleic acid oxidation model. (a) Ferrous ion concentration and (b) oxidation duration. Data are the mean ± standard deviation of triplicate tests. Different letters represent significant difference in the means at a significant level of 0.05](/cms/asset/b7d055dd-55e0-40e8-bd19-a9b4e260c447/ljfp_a_1657888_f0001_b.gif)
Figure 2. Effect of (α)-tocopherol on inhibition of linoleic acid oxidation in Fe2+-vitamin C induced linoleic acid oxidation model. Data are the mean ± standard deviation of triplicate tests
![Figure 2. Effect of (α)-tocopherol on inhibition of linoleic acid oxidation in Fe2+-vitamin C induced linoleic acid oxidation model. Data are the mean ± standard deviation of triplicate tests](/cms/asset/12cf7832-013d-440f-90c7-34662087d7c0/ljfp_a_1657888_f0002_b.gif)
Figure 3. Effect of milk oligopeptides and milk oligopeptides with optimal (α)-tocopherol concentration on inhibition of linoleic acid oxidation in Fe2+-vitamin C-induced linoleic acid oxidation model. (a) Malondialdehyde, (b) Peroxide value and (c) Conjugated diene and triene. Data are the mean ± standard deviation of triplicate tests. # represents significant difference between milk oligopeptides, (α)-tocopherol, milk oligopeptide-(α)-tocopherol and the control on the means at a significant level of 0.05. * means significant difference between milk oligopeptides, milk oligopeptide-(α)-tocopherol and (α)-tocopherol on the means at a significant level of 0.05
![Figure 3. Effect of milk oligopeptides and milk oligopeptides with optimal (α)-tocopherol concentration on inhibition of linoleic acid oxidation in Fe2+-vitamin C-induced linoleic acid oxidation model. (a) Malondialdehyde, (b) Peroxide value and (c) Conjugated diene and triene. Data are the mean ± standard deviation of triplicate tests. # represents significant difference between milk oligopeptides, (α)-tocopherol, milk oligopeptide-(α)-tocopherol and the control on the means at a significant level of 0.05. * means significant difference between milk oligopeptides, milk oligopeptide-(α)-tocopherol and (α)-tocopherol on the means at a significant level of 0.05](/cms/asset/a91756ff-ddf6-4636-b2da-a016b3ea0a5f/ljfp_a_1657888_f0003_b.gif)
Figure 4. Effect of (α)-tocopherol on alteration of maximal absorption wavelength of milk oligopeptides in UV-Vis spectra. a→ e represents the concentration of (α)-tocopherol. The concentrations are: a = 0.0 mmol/L, b = 0.05 mmol/L, c = 0.10 mmol/L, d = 0.20 mmol/L, and e = 0.30 mmol/L
![Figure 4. Effect of (α)-tocopherol on alteration of maximal absorption wavelength of milk oligopeptides in UV-Vis spectra. a→ e represents the concentration of (α)-tocopherol. The concentrations are: a = 0.0 mmol/L, b = 0.05 mmol/L, c = 0.10 mmol/L, d = 0.20 mmol/L, and e = 0.30 mmol/L](/cms/asset/b2a62657-fa3c-46b3-b60b-1e2e4a5fed31/ljfp_a_1657888_f0004_oc.jpg)
Table 1. Fluorescent quenching constant (Ksv) and quenching rate constant (Kq) of milk oligopeptide-(α)-tocopherol complexes
Figure 5. Effect of (α)-tocopherol on reduction of fluorescent intensity of milk oligopeptides. a→ f represents the concentration of (α)-tocopherol. The concentrations are: a = 0.0 × 10−10 mol/L, b = 0.05 × 10−10 mol/L, c = 0.10 × 10−10 mol/L, d = 0.15 × 10−10 mol/L, e = 0,20 × 10−10 mol/L and f = 0.25 × 10−10 mol/L
![Figure 5. Effect of (α)-tocopherol on reduction of fluorescent intensity of milk oligopeptides. a→ f represents the concentration of (α)-tocopherol. The concentrations are: a = 0.0 × 10−10 mol/L, b = 0.05 × 10−10 mol/L, c = 0.10 × 10−10 mol/L, d = 0.15 × 10−10 mol/L, e = 0,20 × 10−10 mol/L and f = 0.25 × 10−10 mol/L](/cms/asset/02ee0e57-0995-4f5b-9ddd-76d98b42f4a6/ljfp_a_1657888_f0005_oc.jpg)
Figure 6. Stern-Volmer fitting curve using milk oligopeptides and (α)-tocopherol. Stern-Volmer formula:
, where F0 and F represent fluorescent intensity of milk oligopeptide before and after the addition of (α)-tocopherol. Kq and Ksv are quenching rate constant and quenching, respectively.
represents the average life span of fluorescent molecule without addition of (α)-tocopherol
![Figure 6. Stern-Volmer fitting curve using milk oligopeptides and (α)-tocopherol. Stern-Volmer formula: F0/F=1+Kqτ0Q= 1+KSVQ, where F0 and F represent fluorescent intensity of milk oligopeptide before and after the addition of (α)-tocopherol. Kq and Ksv are quenching rate constant and quenching, respectively. τ0represents the average life span of fluorescent molecule without addition of (α)-tocopherol](/cms/asset/f0b56fd2-d840-4c9f-9f50-99fb5492b599/ljfp_a_1657888_f0006_b.gif)
Figure 7. Fourier transform infrared spectrum of milk oligopeptides and milk oligopeptide-(α)-tocopherol complexes
![Figure 7. Fourier transform infrared spectrum of milk oligopeptides and milk oligopeptide-(α)-tocopherol complexes](/cms/asset/e83bfcd7-40ad-4aed-8a9d-6db781155fb3/ljfp_a_1657888_f0007_b.gif)
Figure 8. Second derivative and curve-fitting analysis of secondary structure of milk oligopeptide and milk oligopeptide-(α)-tocopherol complex using PeakFit 4.12 software
![Figure 8. Second derivative and curve-fitting analysis of secondary structure of milk oligopeptide and milk oligopeptide-(α)-tocopherol complex using PeakFit 4.12 software](/cms/asset/029947fc-2605-4b53-b1b3-42589725e99e/ljfp_a_1657888_f0008_b.gif)
Table 2. Secondary structure percentage in milk oligopeptides and milk oligopeptide-(α)-tocopherol complexes