Effect of temperature and pH on the gelation, rheology, texture, and structural properties of whey protein and sugar gels based on Maillard reaction

Abstract

This study aimed to determine the effect of initial pH and temperature on whey protein gel formation via the Maillard reaction, including changes in gel structure, rheological and texture properties. The color changes in the whey protein and glucose gels were not significant with increasing heat temperature. High temperature and alkaline conditions promoted exposure to hydrophobic groups such as -SH, which accelerated protein aggregation and gel formation. Moreover, the increased particle size and additional hydrophobic groups contributed to higher elastic modulus (G′) in the whey protein gel. Fluorescence measurements revealed that more tryptophan on the protein surface decreased with increasing temperature, which indicated that exposure to tryptophan could increase the hydrophobicity of the protein gels. Whey proteins formed stronger, gummier, more elastic, and more cohesive gels at 70°C under initial pH 9 conditions, which also increased with the addition of fructose.

Effect of heating temperature on physical, functional, and digestibility properties of Whey Protein Concentrate (WPC)

“…[45]. These results are directly proportional to previous research conducted by [46], where hardness of the whey protein gel has a higher value at 70 o C than 60 and 65 o C. According to [47], the pH of the solution is a crucial factor affecting the appearance and strength of the WPC gel.…”

Effect of ultrasonic power on the stability of low-molecular-weight oyster peptides functional-nutrition W1/O/W2 double emulsion

“…The double emulsion particle size and PDI increased significantly at 70 °C and formed a gel at 90 °C. This may allow the whey proteins to form a stable gel network through aggregation and exchange under thermal induction, which disrupts the interfacial layer, thus allowing gradual gelling of the emulsion [48] . With the increase in temperature, the absolute zeta potential value of the double emulsion decreased significantly from 23.30 ± 0.35 mV to 22.33 ± 0.46 mV, indicating that the heat treatment had a similar effect on the zeta potential of the double emulsion.…”

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

“…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. 12 It is characterized by a progressive decline in permeate flow over time during constant-pressure operation or an increase in transmembrane pressure during constant filtration flow operation.…”

“…13,14 Mitigation methods include the application of external forces such as sonication, heating, electric and magnetic fields, pretreatment of the protein solution through ozonation, chlorination, and aeration, addition of chemicals, dynamic membrane formation via particle deposition, which acts as a secondary membrane reducing protein-membrane interaction, alteration of hydrodynamics using spacers, pulsatile flow, or periodic flow reversal, and finally, enzymatic pretreatment of the feed by adding the transglutaminase (TGase) enzyme. 11,14 Enzymatic cross-linking is sparsely documented in the scientific literature, yet studies have revealed promising results related to increased permeate flux and protein concentration. [11][12][13]15,16 This technique promotes cross-links between lysine and glutamine residues, increasing the molecule's size and facilitating its retention in the filtration membrane.…”

“…11,14 Enzymatic cross-linking is sparsely documented in the scientific literature, yet studies have revealed promising results related to increased permeate flux and protein concentration. [11][12][13]15,16 This technique promotes cross-links between lysine and glutamine residues, increasing the molecule's size and facilitating its retention in the filtration membrane. Enzymatic cross-linking brings additional benefits, such as reducing membrane fouling, preventing scaling, and improving process efficiency.…”