Livestock Products Technology- ICAR JRF/SRF 2024

• Scientific Basis of Pasteurization Standards:
• Complete Destruction of Pathogens: Thermal regimes ($63^\circ\text{C}$ for $30\text{ min}$ LTLT, or $72^\circ\text{C}$ for $15\text{ sec}$ HTST) are designed to destroy the most heat-resistant non-spore-forming vegetative pathogen (Coxiella burnetii and Mycobacterium tuberculosis) (True).
• Inactivation of Alkaline Phosphatase: Alkaline phosphatase is an endogenous milk enzyme whose thermal inactivation curve slightly exceeds that of M. tuberculosis. Absence of residual alkaline phosphatase serves as the statutory test for pasteurization efficiency (True).
• Preservation of Cream Line: Thermal exposure must not excessively denature cryoglobulins, preserving natural gravity creaming (True).
• Fat Globule Size Reduction (B): Achieved by homogenization, not pasteurization.
• nalysis:
• ((A), (C) and (D) only): Correct.

Correct option: (3) (A), (C) and (D) only

• Actin Polypeptide Composition:
• Actin is an abundant, highly conserved eukaryotic myofibrillar contractile protein (molecular weight $\approx 42\text{ kDa}$, 375 amino acid residues).
• Primary sequence analysis shows that small, flexible amino acid residues are highly represented to support globular folding (G-actin) and polymerization into microfilaments (F-actin), with Glycine occurring in exceptionally high concentration (over 28 residues, $\approx 7.5\%$ of total amino acids).
• nalysis:
• (Glycine): Correct.

Correct option: (3) Glycine

• Comparison of Red vs White Muscle Fibers:
• Red Muscle Fibers (Type I / Slow-Twitch):
• High myoglobin content, extensive capillary bed.
• Densely packed with numerous large mitochondria and oxidative enzymes to sustain long-term aerobic endurance without fatigue.
• White Muscle Fibers (Type IIB / Fast-Twitch):
• Low myoglobin, sparse capillaries.
• Fewer mitochondria, relying on anaerobic glycolysis for rapid, high-power bursts; accumulate lactic acid and are easily fatigued.
• nalysis:
• Assertion (A) claims white fibers have higher mitochondria than red fibers (False).
• Reason (R) states white fibers are fast-twitch and easily fatigued (True).
• Hence, Option 4 ((A) is false but (R) is true) is correct.