Improvement of Functional Properties of Whey Protein Isolate Through Glycation and Phosphorylation by Dry Heating

Abstract

Whey protein isolate (WPI) was glycated with maltopentaose (MP) through the Maillard reaction, and the MP-conjugated WPI (MP-WPI) was then phosphorylated by dry heating in the presence of pyrophosphate. Glycation occurred efficiently, and the sugar content of WPI increased approximately 19.9% through the Maillard reaction. The phosphorylation of MP-WPI was enhanced with an increase in the dry-heating time from 1 to 5 d, and the phosphorus content of WPI increased approximately 1.05% by dry heating at pH 4.0 and 85 degrees C for 5 d in the presence of pyrophosphate. The electrophoretic mobility of WPI increased with an increase in the phosphorylation level. The stability of WPI against heat-induced insolubility at pH 7.0 was improved by conjugation with MP alone, and further improved by phosphorylation. Although the emulsifying activity of WPI was barely affected by glycation and phosphorylation, the emulsifying stability of phosphorylated MP-WPI (5 d), was 2.2 times higher than that of MP-WPI. Gelling properties such as hardness, resiliency, and water-holding capacity of heat-induced WPI gel were markedly improved, and the gel was rendered transparent by phosphorylation. The calcium phosphate-solubilizing ability of WPI was enhanced by phosphorylation. These results suggested that phosphorylation by dry heating in the presence of pyrophosphate after conjugation with MP is a useful method for improving the functional properties of WPI.

Functional properties of milk proteins as affected by Maillard reaction induced oligomerisation

“…Increased viscosity of solutions containing Maillard products (Oliver et al, 2006b) may also support these effects. Promoted emulsion stability was confirmed for casein/dextran (Aminlari et al, 2005;Dickinson & Izgi, 1996;Fechner et al, 2007), casein/maltodextrin (Morris et al, 2004), casein/pectin (Al-Hakkak & Kavale, 2002), whey protein/glucose (Nacka et al, 1998), whey protein/lactose (Nacka et al, 1998), whey protein/pectin (Einhorn-Stoll et al, 2005;Mishra et al, 2001), whey protein/carboxymethylcellulose (Kika et al, 2007), whey protein/maltopentaose (Li et al, 2005), b-lactoglobulin/dextran (Dunlap & Côté, 2005) and serum albumin/dextran Maillard products (Dickinson & Izgi, 1996;Dickinson & Semenova, 1992).…”

Transglutaminase-induced cross-linking and glucosamine conjugation of casein and some functional properties of the modified product

“…The available literature shows that food proteins modified by the Maillard reaction include soybean proteins (Diftis, Biliaderis, & Kiosseoglou, 2005), whey proteins (Chevalier, Chobert, Popineau, Nicolas, & Haertlé, 2001;Mishra, Mann, & Joshi, 2001;Li, Enomoto, Ohki, Ohtomo, & Aoki, 2005) and casein (Fechner, Knoth, Scherze, & Muschiolik, 2007;Gu, Abbas, & Zhang, 2009a). However, the Maillard reaction can form undesired browning (Guerra-Hernandez, Gomez, Garcia-Villanova, Sanchez, & Gomez, 2002;Saio et al, 1980) and some mutagenic compounds (Brands, Alink, Van Boekel, & Jongen, 2000), consequently affecting the sensory attributes of final products negatively or giving rise to safety issues.…”

Functional egg white–pectin conjugates prepared by controlled Maillard reaction

“…Gum arabic is a naturally occurring glyco-conjugate and has been studied and characterised as an emulsifier by many researchers (Al-Assaf et al, 2006;Kim et al, 1996;Randall et al, 1988a,b). Researchers have attempted to synthesise high performance glyco-conjugates using different proteins, such as whey protein isolate, casein, sodium caseinate, egg proteins and others, and a wide range of polysaccharides Dickinson, 2003, 2007;Al-Hakkak and Kavale, 2002;Einhorn-Stoll et al, 2005;Fechner et al, 2007;Ibanoglu and Ercelebi, 2007;Li et al, 2005;Oliver et al, 2006). Dairy proteins have been the focus of such activity for a number of years, and there are many papers dealing with the modification, improvement and enhancement of emulsification and stabilising properties of these proteins.…”