Separation Technologies for Whey Protein Fractionation

Abstract

Whey is a by-product of cheese, casein, and yogurt manufacture. It contains a mixture of proteins that need to be isolated and purified to fully exploit their nutritional and functional characteristics. Protein-enriched fractions and highly purified proteins derived from whey have led to the production of valuable ingredients for many important food and pharmaceutical applications. This article provides a review on the separation principles behind both the commercial and emerging techniques used for whey protein fractionation, as well as the efficacy and limitations of these techniques in isolating and purifying individual whey proteins. The fractionation of whey proteins has mainly been achieved at commercial scale using membrane filtration, resin-based chromatography, and the integration of multiple technologies (e.g., precipitation, membrane filtration, and chromatography). Electromembrane separation and membrane chromatography are two main emerging techniques that have been developed substantially in recent years. Other new techniques such as aqueous two-phase separation and magnetic fishing are also discussed, but only a limited number of studies have reported their application in whey protein fractionation. This review offers useful insights into research directions and technology screening for academic researchers and dairy processors for the production of whey protein fractions with desired nutritional and functional properties.

Investigating and Optimizing Insulin Partitioning with Conjugated Au Nanoparticles in Aqueous Two-Phase Systems Using Response Surface Methodology

“…The decrease in the partitioning coefficient between pH 8 and 9 may be attributed to changes in the insulin molecular structure and its interaction with the aqueous environment, e.g., hydrophobic interactions. 38,39 The conjugation to AuNPs changed the surface properties, and the high surface charge of the AuNPs contributes to their excellent partitioning. 20,40 Also, as the molecular weight of dextran increases, the gap between polymer networks decreases, reducing the space available for molecules in the dextran phase.…”

“…When the pH of a biomolecule rises above its isoelectric point (pI), it becomes more negative, resulting in an increase in the partition coefficient. , Changes in pH causes a shift in the phase preference due to variations in insulin surface charge (pI = 5.4), and the magnitude of partitioning depends on surface charges. The decrease in the partitioning coefficient between pH 8 and 9 may be attributed to changes in the insulin molecular structure and its interaction with the aqueous environment, e.g., hydrophobic interactions. , The conjugation to AuNPs changed the surface properties, and the high surface charge of the AuNPs contributes to their excellent partitioning. , Also, as the molecular weight of dextran increases, the gap between polymer networks decreases, reducing the space available for molecules in the dextran phase. This leads to the volume exclusion effect, which causes the biomolecules to partition into the PEG phase, resulting in an increase in the AuNPs/insulin partition coefficient …”

Whey filtration: a review of products, application, and pretreatment with transglutaminase enzyme

“…3,18 The fractionation of whey components into high-value-added products is based on the intrinsic value of constituents such as lactose, proteins, and minerals. 9 Various membrane filtration methods are employed, each with its own operational conditions, composition, and pore size, enabling the separation of characteristic whey components. 19 The choice of filtration method depends on the desired components for separation and the desired properties of the final product.…”

“…The removal of salts from whey through techniques like nanofiltration (up to 40% mineral removal-D40), electrodialysis (up to 70% mineral removal-D90), and ion exchange (up to 90% mineral removal-D90) can add more value, resulting in the production of demineralized whey powders (such as D40, D70, and D90). 9 As lactose permeates through membrane separation processes, whey proteins retained by ultrafiltration membranes are typically recovered and simultaneously concentrated to obtain whey protein concentrate (WPC), which can contain up to 80% protein, and whey protein isolate (WPI), which can contain up to 90% protein relative to the total product weight. 9,10 Nonetheless, the membrane filtration system for whey faces a challenge related to fouling, which is directly linked to the economic sustainability of these systems.…”

“…9 As lactose permeates through membrane separation processes, whey proteins retained by ultrafiltration membranes are typically recovered and simultaneously concentrated to obtain whey protein concentrate (WPC), which can contain up to 80% protein, and whey protein isolate (WPI), which can contain up to 90% protein relative to the total product weight. 9,10 Nonetheless, the membrane filtration system for whey faces a challenge related to fouling, which is directly linked to the economic sustainability of these systems. 11 Fouling occurs when whey molecules or aggregates deposit on the membrane surface or within its pores, gradually obstructing them and impeding filtration.…”