Unit 3

• Thermal Conditioning of Milk ($90^\circ\text{C}$ for 10 min):
• Heat-Induced Whey Protein-Casein Complexation:
• High-temperature preheating ($90^\circ\text{C} / 10\text{ min}$) denatures globular whey proteins, primarily $\beta$-lactoglobulin, exposing free sulfhydryl groups.
• Denatured $\beta$-lactoglobulin forms disulfide-linked covalent complexes with $\kappa$-casein on the micelle surface, preventing micellar heat coagulation and substantially increasing heat stability during subsequent sterilization.
• Conclusion: Increase in heat stability (Option 3).

Correct option: (3) Increase in heat stability

• Free Radical Polymerization in SDS-PAGE Gel Casting:
• Initiator Chemistry:
• Polyacrylamide gel casting uses acrylamide monomer and N,N'-methylenebisacrylamide crosslinker.
• Polymerization is initiated by free sulfate radicals produced by Ammonium persulfate (APS), catalyzed by TEMED (tetramethylethylenediamine).
• Conclusion: Ammonium persulfate (Option 1).

Correct option: (1) Ammonium persulfate