Modulating the textural characteristics of whey protein nanofibril gels with different concentrations of calcium chloride

Abstract

Protein nanofibrils with 10-20 nm diameters were formed by heating whey protein solution at pH 2.0. Nanofibrils solution was deacidified slowly through dialysis followed by adding different amounts of CaCl2 (0-80 mM) into the dialysis water resulting in formation of a soft viscoelastic gel over time. The gel fabricated from the nanofibrils solution dialyzed against distilled water with 0 mM CaCl2 had zero ash content. Fourier transform infra-red spectroscopy revealed a change in the pattern of hydrogen bond formation in gel network by calcium chloride. The higher the ash content of gels, the lower was the storage modulus and fracture stress of samples. Gels with higher ash contents had a more porous microstructure which was attributed to the diminished hydrophobic interactions and hydrogen bonding among nanofibrils by the action of chloride. Higher ash contents also led to higher water holding capacity of gels which was attributed to the influence of the strongly hydrated calcium ions that interacted with the non-charged regions of proteins via site-specific interactions.

Nanofibrils of food‐grade proteins: Formation mechanism, delivery systems, and application evaluation

“…Farjami et al (2016) showed novel ashless hydrogels as candidates to deliver BCs that are simply combined with ions to reduce the therapeutic effect. By slow dialysis, they adjusted the pH of WPI nanofibril solution to pH 2.0 to form hydrogels without adding divalent metal cations (Ca 2+ ), which they dubbed ashless hydrogels (Farjami et al, 2016). Aerogels are high porosity materials with a low density and large surface area (Liu et al, 2019).…”

“…Although customized gel systems for BCs are still a daunting challenge, researchers have exerted a series of well-designed schemes to fabricate two classes of novel gel systems to meet the specialty of BCs, including ashless hydrogels and aerogels. Farjami et al (2016) showed novel ashless hydrogels as candidates to deliver BCs that are simply combined with ions to reduce the therapeutic effect. By slow dialysis, they adjusted the pH of WPI nanofibril solution to pH 2.0 to form hydrogels without adding divalent metal cations (Ca 2+ ), which they dubbed ashless hydrogels (Farjami et al, 2016).…”

Protein nanofibrils: Preparation, properties, and possible applications in industrial nanomaterials

“…An alternative way of provoking gel formation without adding cations is through dialysis. An ash-free whey-PNF gel was created through a deacidification step by slow dialysis against water [112]. The ejection of hydronium ions increased pH toward the isoelectric point of the protein and diminished the repulsion between PNFs, which activated the formation of the gel.…”

Cold-set hydrogels made of whey protein nanofibrils with different divalent cations

“…− fibril) is a prerequisite [2]. Recently, Farjami et al [5] gelled whey protein nanofibrils solution through slow deacidification by extensive dialysis against water. The obtained ash-free gel had a higher storage modulus and fracture stress than the gels formed via dialysis with CaCl 2 -enriched waters.…”