Physicochemical properties and emulsion stabilization of rice dreg glutelin conjugated with κ-carrageenan through Maillard reaction.
BACKGROUND
Rice dreg is an underutilized source of cereal protein with good potential for application in the food industry. Glutelin represents about 850 g kg(-1) of total storage protein in rice dreg. The objective of this study was to characterize the physicochemical properties and emulsion stabilization of the Maillard type conjugate formed with rice dreg glutelin (RDG) and κ-carrageenan (1:2 weight ratio) dry-heated at 60 °C and 79% relative humidity for 24 h.


RESULTS
Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Fourier transform-infrared analysis provided evidence on the formation of the Maillard type conjugation. Amino acid analysis suggested that the major locus during the Maillard reaction were lysine and arginine. Circular dichroism spectra showed decreasing amounts of α-helix and β-strand in the products with increment in the amount of turns and random coil. Conjugation with κ-carrageenan could significantly improve solubility of RDG (P < 0.05). Measurements of mean droplet size and creaming stability in oil-in-water emulsions showed that the conjugate was more effective at stabilizing emulsions at low pH or in the presence of high ionic strength.


CONCLUSIONS
The Maillard reaction can be successfully used as a coupling method for RDG and κ-carrageenan to form the conjugate with improved solubility and emulsion stabilization.
State Key Laboratory of Food Science and Technology, Nanchang University, Jiangxi 330047, People's Republic of China.
Yanxue
Y
Du
Suhua
S
Shi
Yan
Y
Jiang
Hua
H
Xiong
Meng Wai
MW
Woo
Qiang
Q
Zhao
Chunqing
C
Bai
Qiang
Q
Zhou
Wenjing
W
Sun
D000596:Amino Acids / Q000032:analysis; D002351:Carrageenan / Q000737:chemistry*; D045703:Emulsifying Agents / Q000737:chemistry*; D004655:Emulsions / Q000737:chemistry*; D005983:Glutens / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007477:Ions; D015416:Maillard Reaction; D012275:Oryza / Q000737:chemistry*; D010316:Particle Size; D011487:Protein Conformation; D012995:Solubility; D014867:Water
D000596:Amino Acids; D045703:Emulsifying Agents; D004655:Emulsions; D007477:Ions; D014867:Water; D005983:Glutens; D002351:Carrageenan