Formation of soy protein isolate-dextran conjugates by moderate Maillard reaction in macromolecular crowding conditions.
BACKGROUND
Several methods have been reported for the conjugation of proteins with polysaccharides. Protein-polysaccharide conjugates can be formed by traditional dry heating, but this process is not attractive from an industrial viewpoint, and no commercial conjugates have been manufactured in this way. In the present study, in order to develop a more practical reaction method, macromolecular crowding was used to attach polysaccharides to proteins.


RESULTS
Soy protein isolate-dextran conjugates (SDCs) were prepared via the initial stage of the Maillard reaction in macromolecular crowding conditions. The impact of various processing conditions on the formation of SDCs was investigated. The optimal conditions chosen from the experiments were a soy protein isolate/dextran ratio of 1:1 (w/w), a pH of 6.5, a reaction temperature of 60 °C and a reaction time of 30 h. Circular dichroism spectroscopy showed that the secondary and tertiary structures of the conjugates were changed significantly. Structural flexibility increased, allowing better display of their functional characteristics. The conjugates had a composition with various sizes, especially macromolecules, according to gel permeation chromatography. Thermal analysis showed that the thermal stability of the conjugates was improved.


CONCLUSIONS
The production of SDCs under macromolecular crowding conditions appears to be an effective and promising technique, representing an advance over classic protein glycosylation methods.
School of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, Guangdong, China.
Xiu-Ying
XY
Zhuo
Jun-Ru
JR
Qi
Shou-Wei
SW
Yin
Xiao-Quan
XQ
Yang
Jian-Hua
JH
Zhu
Li-Xin
LX
Huang
D002152:Calorimetry, Differential Scanning; D055598:Chemical Phenomena; D002942:Circular Dichroism; D003911:Dextrans / Q000737:chemistry*; D004040:Dietary Carbohydrates / Q000032:analysis; D004655:Emulsions; D005524:Food Technology; D005526:Food, Formulated / Q000032:analysis*; D006031:Glycosylation; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D015416:Maillard Reaction; D055595:Mechanical Phenomena; D014674:Plant Proteins, Dietary / Q000737:chemistry* / Q000302:isolation & purification; D018583:Pliability; D055550:Protein Stability; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D030262:Soybean Proteins / Q000737:chemistry* / Q000302:isolation & purification; D013997:Time Factors
D003911:Dextrans; D004040:Dietary Carbohydrates; D004655:Emulsions; D014674:Plant Proteins, Dietary; D030262:Soybean Proteins