Dairy Packaging, Sensory & By-Products

Manufacturing and crystallization physics of lactose:

• Assertion (A) is true: In commercial lactose processing, refined crystalline alpha-lactose monohydrate is dried to remove free surface moisture (target $0.5\%$ for edible grade and $\le 0.1\%$ for pharmaceutical USP grade) with product temperatures maintained below $93^\circ\text{C}$ to prevent thermal conversion into anhydrous forms or beta-lactose.
• Reason (R) is true: Rapid flash or spray drying of lactose solutions deprives molecules of the time required to nucleate and arrange into a crystal lattice, yielding an amorphous, non-crystalline 'lactose glass' preserving the liquid alpha/beta equilibrium ratio ($1 : 1.68$).
• However, (R) describes amorphous glass formation, whereas (A) specifies standard moisture drying of crystalline lactose; hence (R) is NOT the direct explanation of (A).
  
  Option analysis:
• Both (A) and (R) are true and (R) is the correct explanation of (A): Incorrect.
• Both (A) and (R) are true but (R) is NOT the correct explanation: Correct.
• is true but (R) is false: Incorrect.
• is false but (R) is true: Incorrect.

Valio immobilized lactase system (Finland):

• Statement (A) is correct: The Valio process utilizes beta-galactosidase (lactase) derived from the fungus Aspergillus niger immobilized on a porous phenol-formaldehyde or silica resin.
• Statement (B) is incorrect: Fungal lactase from A. niger is an acid lactase operating at optimal acidic conditions ($pH\text{ }3.5\text{ to }4.0$, temperature $50\text{ to }55^\circ\text{C}$), NOT neutral pH 7.
• Statement (C) is correct: Because the enzyme requires acidic pH ($3.5\text{ to }4.0$), it cannot treat neutral products like whole milk or sweet whey without prior acid adjustment/demineralization.
• Statement (D) is correct: Hydrolyzed whey syrup (rich in sweet glucose and galactose) is used as a natural sweetening syrup in fruit yogurts, ice creams, beverages, and bakery goods.

Lipid characteristics of buttermilk:

• Statement (A) is correct: Palmitic acid ($C_{16:0}$, approximately $28\%$ to $30\%$) is the predominant fatty acid in buttermilk lipids.
• Statement (B) is INCORRECT: Milk phospholipids consist exclusively of long-chain fatty acids ($C_{16}$ to $C_{24}$, such as palmitic, stearic, oleic, and linoleic acids). Short-chain fatty acids ($C_4$ to $C_{10}$, such as butyric and caproic acids) are esterified in core triglycerides and are completely absent from polar phospholipids.
• Statement (C) is correct: Buttermilk polar lipids derived from the fat globule membrane contain phosphatidylcholine (lecithin), phosphatidylethanolamine (cephalin), sphingomyelin, and minor glycolipids (cerebrosides and gangliosides).
• Statement (D) is correct: Fatty acids esterified in milk phospholipids are approximately $40\%$ saturated and $60\%$ unsaturated fatty acids.