Unit 3

• Physical State of Lactose in Spray-Dried Milk Powder:
• Amorphous Glass State:
• In spray drying, moisture evaporates within seconds, causing rapid viscosity rise that freezes lactose molecules into an amorphous, non-crystalline glass state.
• Amorphous lactose glass is thermodynamically metastable and hygroscopic; moisture absorption above critical water activity ($a_w \gt 0.43$) triggers crystallization into $\alpha$-lactose monohydrate, causing powder caking.
• Conclusion: Glass (Option 3).

Correct option: (3) Glass

• Whey Protein Nitrogen Index (WPNI) Classification:
• ADPI Standards for Nonfat Dry Milk:
• Measures undenatured whey protein nitrogen per gram of powder ($\text{mg WPN/g}$):
• Low-Heat Milk Powder: $\ge 6.0\text{ mg WPN/g}$ (very low level of protein denaturation).
• Medium-Heat Milk Powder: $1.5 - 5.9\text{ mg WPN/g}$.
• High-Heat Milk Powder: $\le 1.5\text{ mg WPN/g}$ (severe denaturation).
• Conclusion: ≥ 6.0 (Option 2).

Correct option: (2) 26.0

• High-Pressure Processing (HPP / Pascalization) Technology:
• Preservation Mechanics:
• Applies isostatic hydrostatic pressures ($100 - 800\text{ MPa}$) uniformly throughout food packages without thermal heat.
• Enzyme and Spoilage Inactivation: Inactivates vegetative spoilage cells and destabilizes enzymes.
• Retention of Sensory Qualities: Leaves covalent bonds unaffected, preserving small molecular weight vitamins, natural colors, textures, and volatile aroma profiles.
• Statement (B) is false: Bacterial endospores (e.g., Clostridium botulinum) resist high hydrostatic pressures at ambient temperatures unless combined with heat.
• Conclusion: (A), (C) only (Option 2).

Correct option: (2) (A), (C) only.