Functional Improvements in Food Proteins in Multiple Aspects by Conjugation with Saccharides: Case Studies of .BETA.-Lactoglobulin-Acidic Polysaccharides Conjugates.

Abstract

Many studies on the conjugates of proteins and saccharides (neoglycoproteins) have been carried out over the past 20 years to improve the function of proteins. However, most have been carried out by attachment or elimination of low-molecular weight molecules for single purposes. The structure-function relationship of the conjugates has not been well understood, and little is known about the improvement of proteins by conjugation with polysaccharides. We sought to achieve functional improvements in food proteins in multiple aspects by conjugation with charged polysaccharides. We chose bovine ␤-lactoglobulin (␤-LG) as the target protein for improvement of the function and attached carboxymethyl dextrans (CMDs) of different molecular weight (10, 40, 70 and 162 kDa) covalently. After conjugation and purification, we explored the structure of the ␤-LG-CMD conjugates to prove that we could prepare conjugates while maintaining the native-like structure of protein molecule. By conjugation with CMDs, enhancement of thermal stability, improvement in the emulsifying properties and reduction of immunogenicity of ␤-LG could be achieved. Increases in the CMD content and net charge were viewed as the major factors in the improved emulsifying properties. Conjugation with high saccharide content using polysaccharides of higher molecular weight is believed to be effective in reduced immunogenicity of ␤-LG.

Monoliths for the purification of whey protein–dextran conjugates

“…In the food industry, protein-polysaccharide conjugates are useful because of improved functional properties over proteins [6][7][8][9][10][11]. Conjugates have improved heat and pH stability, solubility, emulsification, and gelation properties and may offer lower astringency and allergenicity compared to unmodified proteins [12][13][14].…”

Functional Improvements to β-Lactoglobulin by Preparing an Edible Conjugate with Cationic Saccharide Using Microbial Mransglutaminase (MTGase)

“…To achieve such multiple functional improvements, we have been studying on the neoglycoconjugates of BLG. Studies on the neoglycoconjugates of proteins have been widely investigated during the last 30 years, 6) and various improvements in the function of proteins have been achieved. We have shown that improved emulsifying properties [7][8][9] and reduced immunogenicity [10][11][12] of BLG could be achieved by conjugating with carboxymethyl dextran.…”

Functional improvements in β-lactoglobulin by conjugating with soybean soluble polysaccharide

“…We have been studying the neoglycoconjugates of BLG to achieve this. 7) Protein conjugation can simultaneously achieve reduced allergenicity and improved functional properties (such as thermal stability, solubility, and emulsifying ability) while maintaining the physiological functions of proteins. We focused our previous studies on the neoglycoconjugates of BLG.…”

“…We focused our previous studies on the neoglycoconjugates of BLG. BLG was conjugated with carboxymethyl dextran 7) or chitosan by means of a water-soluble carbodiimide 8) and with acidic oligosaccharides (alginic acid oligosaccharides or phosphoryl oligosaccharides) by the Maillard reaction. 9) We also prepared the conjugates by DNA recombinant technology 10) and by using microbial transglutaminase.…”