Effect of β-Lactoglobulin A and B Whey Protein Variants on the Rennet-Induced Gelation of Skim Milk Gels in a Model Reconstituted Skim Milk System

Variation in the measured concentration of β-LG after CN precipitation as a function of the amount of β-LG added prior to (○) and after (■) heat treatment (65°C for 30min). (A) β-Lactoglobulin A-A and (B) β-LG B-B. Dotted (unheated samples) and solid (heated samples) lines correspond to best-fit linear regression curves.

Variation in the concentration of β-LG after CN precipitation as a function of the amount of β-LG added prior to (○) and after (■) heat treatment (65°C for 30min). (A) β-Lactoglobulin A in phenotype A-B and (B) β-LG B in phenotype A-B. Dotted (unheated samples) and solid (heated samples) lines correspond to best-fit linear regression curves.

Evolution of the storage modulus (ω=6 rad/s; γ=7%; 32°C), G′, as a function of time for rennet-induced heated skim milk (HSM) gels with added (A) β-LG A, (B) β-LG B, and (C) β-LG A-B. Symbol key: (□) HSM; (○) HSM + 0.225% whey protein; (■) HSM + 0.45% whey protein; (▾;) HSM + 0.675% whey protein; (♢) HSM + 0.90% whey protein; (●) HSM + 1.35% whey protein.

Variation in the final storage, G′, and loss, G″, moduli as a function of whey protein concentration for rennet-induced heated skim milk (HSM) gels with added whey protein variants (ω=6 rad/s; γ=7%). Final storage modulus, G′, at (A) 32°C and (B) 10°C; final loss modulus, G″, at (C) 32°C and (D) 10°C. Symbol key: (•) HSM with added β-LG B; (■) HSM with added β-LG A; (▾;) HSM with added β-LG A-B.

Variation in the final loss tangent, tan δ, as a function of whey protein concentration for rennet-induced heated skim milk (HSM) gels added with whey protein variants (ω=6 rad/s; γ=7%; 32°C) at (A) 32°C and (B) 10°C. Symbol key: (■) HSM with added β-LG A; (●) HSM with added β-LG B; (▾;) HSM with added β-LG A-B.

Critical gel time (t_gel) of rennet-induced heated skim milk (HSM) gels as a function of whey protein concentration (ω=6 rad/s; γ=7%; 32°C). Symbol key: (■) HSM with added β-LG A; (●) HSM with added β-LG B; (▾;) HSM with added β-LG A-B.