Properties of partially denatured whey protein products: Formation and characterisation of structure

Abstract

a b s t r a c tPartially denatured whey protein (PDWPC) products have been manufactured using a controlled heating process that allows control of the degree of denaturation of the whey proteins. This is assessed by following the change in free sulphydryl content of the protein as heating progresses. This allows the formation of soluble whey protein aggregates of diverse particle size and morphology. The PDWPC's have been made using different manufacturing conditions (temperature, pH, degree of denaturation) to give aggregated PDWPC powders with a degree of denaturation in the range 45e98% and particle size 3 e17 mm. Particle size analysis, scanning electron microscopy and density analysis show that the particles have aggregated structures that range from compact, particulate gel-like to fibrillar phase-separated structures, with intermediate structures formed under some conditions. These structures are consistent with the known gel structures formed in whey protein concentrate gels. The structure of the PDWPC particles differs from that of microparticulated whey proteins. The possibility of using PDWPC's as ingredients tailored to the needs of food manufacturers is discussed.

Extrusion modifies some physicochemical properties of milk protein concentrate for improved performance in high‐protein nutrition bars

“…Extruded MPC80s had lower free sulfhydryl content than the control ( P < 0.05); melt temperature did not have a significant effect ( P > 0.05) (Table ). The free sulfhydryl concentration of E116 was numerically lower than E95 and E105, which suggested more protein denaturation and disulfide bond formation and/or free sulfhydryl oxidations at higher processing temperatures . SDS inclusion in the free sulfhydryl assay buffer did not affect ( P > 0.05) measureable free sulfhydryl concentration of the powders (Table ).…”

Electrostatic complexes of whey protein and pectin as foaming and emulsifying agents

“…It is also possible that similar effects will be observed with thickening and gelation properties and work continues in this area. Our own work on controlling structure in WPC aggregates [6,7] has shown that control over solution viscosity can be achieved through controlled thermal aggregation so we are hopeful that similar effects can be achieved in the more complex binary aggregates of WPC and pectin. If this is achieved, it will open up the possibility of functional ingredients that can be more closely tailored to the functional requirements of a particular product or manufacturer.…”

“…[1][2][3] They have also been used to replace fats in foods due to their ability to mimic the sensory, optical, and rheaological properties of lipid droplets. [4,5] In view of this, there has been a growing interest in the fabrication of biopolymer microparticles made from proteins alone [6,7] or mixed protein and polysaccharide complexes. [3,[8][9][10][11][12][13] Molecular complexes form via interaction (commonly electrostatic) between two biopolymer molecules.…”

Liquid Whey Protein Concentrates Produced by Ultrafiltration as Primary Raw Materials for Thermal Dairy Gels

“…These include the protein type (molecular mass and amino acid composition) (6), protein hydrophobicity and free sulphydryl groups (7), protein concentration (8), the proportions of individual whey proteins in the mixture (9), the type and amount of salts (8,10,11), lipids (12), lactose (6), sucrose (13) present in the formula-tion, process conditions (pH, temperature, heating and cooling rate) (14,15), and/or specific treatments such as microparticulation of whey proteins (16)(17)(18). Among these factors, attention has been focused on protein concentration and pH.…”