In avian egg anatomy, the clear, transparent, multi-layered semipermeable membrane that immediately envelops and maintains the spherical integrity of the egg yolk is biologically termed the vitelline membrane. As the egg ages, water migrates from albumen into the yolk via osmosis, weakening the vitelline membrane until it flattens or ruptures easily upon cracking.

Option analysis:

• Edwards membrane: Non-existent anatomical structure.
• Vitelline membrane: Correct, anatomical name for the egg yolk membrane.
• Edwin membrane: Non-existent term.
• Lawrence membrane: Non-existent term.

Ovalbumin is the predominant protein in avian egg white (albumen), constituting approximately $54\%$ of the total protein content. It is a monomeric phosphoglycoprotein responsible for the gelling and foaming properties of egg white.

Option analysis:

• Avidin: Minor protein ($0.05\%$) that binds biotin.
• Ovomucoid: Constitutes about $11\%$ of egg white protein, a trypsin inhibitor.
• Mucin: Minor structural glycoprotein in chalaziferous layer and thick albumen.
• Ovalbumin: Correct, comprises over half ($54\%$) of all egg white protein.

Standard meat curing formulations consist of sodium chloride ($NaCl$, for moisture extraction and microbial inhibition), sodium nitrite ($NaNO_2$, for cured pink color formation and Clostridium botulinum inhibition), and sodium nitrate ($NaNO_3$, slow reservoir for nitrite). Sodium sulphate ($Na_2SO_4$) plays no role in curing and is not an authorized curing salt.

Option analysis:

• Sodium nitrate: Standard curing salt converted to nitrite by bacterial reduction.
• Sodium sulphate: Correct, not a meat curing agent.
• Sodium nitrite: Primary curing salt forming nitrosylmyoglobin.
• Sodium chloride: Fundamental base salt in all curing mixtures.