Structure and antioxidant activity of soy protein isolate-dextran conjugates obtained by TiO2 photocatalysis.
The aim of this study was to investigate the structural characteristics and antioxidant activities of soy protein isolate- (SPI-) dextran conjugates obtained by TiO2 photocatalysis treatment. Results revealed that the UV-vis absorption and the fluorescence intensity increased as the photocatalytic power increased (P < 0.05). Higher photocatalytic power could promote the extent of glycation and the formation of high molecular weight SPI-dextran conjugates, which were evidenced by free amino group content and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The Fourier transform infrared (FT-IR) spectra suggested that the amide I, II, and III bands of SPI were altered by the glycation induced by TiO2 photocatalysis. Moreover, significant changes of secondary structure occurred in SPI-dextran conjugates. The α-helix, β-sheet, β-turns, and random coil were changed from approximately 10.6%, 37.9%, 12.9%, and 38.6% to 3.8%, 10.4%, 17.7%, and 68.8%, respectively, after treatment at photocatalytic power of 1000 W. In addition, SPI-dextran conjugates obtained by TiO2 photocatalysis treatment exhibited high hydroxyl radical scavenging activity and possessed increased reducing power. All data indicated that TiO2 photocatalysis was an efficient method for promoting protein-polysaccharide copolymerisation.
School of Chemistry and Chemical Engineering and Institute of Food Science & Engineering, Lingnan Normal University, Zhanjiang 524048, China ; Engineering Research Center of Starch and Vegetable Protein Processing, South China University of Technology, Ministry of Education, Guangzhou 510640, China ; Development Center for New Materials Engineering and Technology, Lingnan Normal University, Zhanjiang 524048, China.
Bei
B
Jin
School of Chemistry and Chemical Engineering and Institute of Food Science & Engineering, Lingnan Normal University, Zhanjiang 524048, China ; Development Center for New Materials Engineering and Technology, Lingnan Normal University, Zhanjiang 524048, China.
Xiaosong
X
Zhou
Engineering Research Center of Starch and Vegetable Protein Processing, South China University of Technology, Ministry of Education, Guangzhou 510640, China.
Bing
B
Li
School of Chemistry and Chemical Engineering and Institute of Food Science & Engineering, Lingnan Normal University, Zhanjiang 524048, China.
Caiyan
C
Chen
School of Chemistry and Chemical Engineering and Institute of Food Science & Engineering, Lingnan Normal University, Zhanjiang 524048, China.
Xiaosa
X
Zhang
School of Chemistry and Chemical Engineering and Institute of Food Science & Engineering, Lingnan Normal University, Zhanjiang 524048, China.
Siqiao
S
Chen
D000975:Antioxidants / Q000032:analysis / Q000138:chemical synthesis*; D002384:Catalysis; D003911:Dextrans / Q000737:chemistry* / Q000528:radiation effects; D008027:Light; D058726:Nanoconjugates / Q000737:chemistry* / Q000528:radiation effects; D010777:Photochemistry / Q000379:methods; D030262:Soybean Proteins / Q000737:chemistry* / Q000528:radiation effects; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects
D000975:Antioxidants; D003911:Dextrans; D058726:Nanoconjugates; D030262:Soybean Proteins; C009495:titanium dioxide; D014025:Titanium