TY - JOUR

T1 - Unaided efficient transglutaminase cross-linking of whey proteins strongly impacts the formation and structure of protein alginate particles

AU - Madsen, Mikkel

AU - Khan, Sanaullah

AU - Kunstmann, Sonja

AU - Aachmann, Finn L.

AU - Ipsen, Richard

AU - Westh, Peter

AU - Emanuelsson, Cecilia

AU - Svensson, Birte

N1 - Publisher Copyright: © 2022 The Authors

PY - 2022

Y1 - 2022

N2 - There is a dogma within whey protein modification, which dictates the necessity of pretreatment to enzymatic cross-linking of β-lactoglobulin (β-Lg). Here microbial transglutaminase (MTG) cross-linked whey proteins and β-Lg effectively in 50 mM NaHCO3, pH 8.5, without pretreatment. Cross-linked β-Lg spanned 18 to >240 kDa, where 6 of 9 glutamines reacted with 8 of 15 lysines. The initial isopeptide bond formation caused loss of β-Lg native structure with t1/2 = 3 h, while the polymerization occurred with t1/2 = 10 h. Further, cross-linking effects on protein carbohydrate interaction have been overlooked, leaving a gap in understanding of these complex food matrices. Complexation with alginate showed that β-Lg cross-linking decreased onset of particle formation, hydrodynamic diameter, stoichiometry (β-Lg/alginate) and dissociation constant. The complexation was favored at higher temperatures (40 °C), suggesting that hydrophobic interactions were important. Thus, β-Lg was cross-linked without pretreatment and the resulting polymers gave rise to altered complexation with alginate.

AB - There is a dogma within whey protein modification, which dictates the necessity of pretreatment to enzymatic cross-linking of β-lactoglobulin (β-Lg). Here microbial transglutaminase (MTG) cross-linked whey proteins and β-Lg effectively in 50 mM NaHCO3, pH 8.5, without pretreatment. Cross-linked β-Lg spanned 18 to >240 kDa, where 6 of 9 glutamines reacted with 8 of 15 lysines. The initial isopeptide bond formation caused loss of β-Lg native structure with t1/2 = 3 h, while the polymerization occurred with t1/2 = 10 h. Further, cross-linking effects on protein carbohydrate interaction have been overlooked, leaving a gap in understanding of these complex food matrices. Complexation with alginate showed that β-Lg cross-linking decreased onset of particle formation, hydrodynamic diameter, stoichiometry (β-Lg/alginate) and dissociation constant. The complexation was favored at higher temperatures (40 °C), suggesting that hydrophobic interactions were important. Thus, β-Lg was cross-linked without pretreatment and the resulting polymers gave rise to altered complexation with alginate.

KW - Dynamic light scattering

KW - Far- and near-UV CD

KW - Intrinsic and ANS fluorescence spectra

KW - LC-MS/MS cross-link identification

KW - Molecular dynamics inter-residue distance analysis

KW - Size exclusion chromatography

U2 - 10.1016/j.fochms.2022.100137

DO - 10.1016/j.fochms.2022.100137

M3 - Journal article

C2 - 36164490

AN - SCOPUS:85138554980

VL - 5

JO - Food Chemistry: Molecular Sciences

JF - Food Chemistry: Molecular Sciences

SN - 2666-5662

M1 - 100137

ER -