Advances in Dairy Processing

• Mass Transport through Food Packaging Polymers:
• Pressure dependence: Gas permeability ($P = D \times S$) through polymeric barriers increases as pressure differential increases due to higher gas solubility and matrix plasticization.
• Temperature dependence: Gas diffusion coefficient increases exponentially with temperature according to Arrhenius kinetics ($D = D_0 e^{-E_d/RT}$).
• Polymer polarity: Non-polar hydrocarbon polymers (Polyethylene - LDPE/HDPE, Polypropylene) lack hydrophilic groups, exhibiting excellent water vapor barrier properties (low WVTR).
• Statement C is false: Polar polymers (EVOH, cellophane, polyamide) absorb moisture and possess poor water barrier properties.
• Conclusion: A, B, D only (Option 2).

Correct option: (2) A.B,D only

• Water Vapor Barrier Properties in Packaging:
• Aluminium Foil: Provides an absolute, near-zero barrier to water vapor, oxygen, aromas, and light when pinhole-free (thickness $\ge 25\,\mu\text{m}$, Water Vapor Transmission Rate, $\text{WVTR} \approx 0\text{ g/m}^2\text{/day}$). It is the gold standard impermeable moisture barrier used in flexible laminates.
• Polyethylene (PE): Good moisture barrier, but permeable compared to aluminium foil.
• Polypropylene (PP): Moderate moisture barrier.
• Polystyrene (PS): Poor water vapor barrier with high permeability.
• Correct Option: Option 2 (Aluminium foil).

• Lactulose Formation via Thermal Isomerization of Lactose:
• Lobry de Bruyn-Alberda van Ekenstein Transformation:
• Under intense heat treatment (e.g., in in-bottle sterilized or UHT milk), lactose (4-O-$\beta$-D-galactopyranosyl-D-glucose) isomerizes into Lactulose (4-O-$\beta$-D-galactopyranosyl-D-fructose).
• Physiological & Diagnostic Properties:
• Non-digestible disaccharide utilized clinically as an osmotic laxative and hepatic encephalopathy therapeutic, and serves as an official chemical index of severe milk heat treatment.
• Conclusion: Lactulose (Option 2).

Correct option: (2) Lactulose

• Inulin and Commercial Extraction:
• Inulin: A storage polysaccharide composed of linear chains of fructose units connected by $\beta(2\to 1)$ fructosyl-fructose glycosidic linkages, terminated with an $\alpha(1\to 2)$ D-glucose unit.
• Chicory Root (Cichorium intybus): The primary commercial and industrial agronomic source of inulin, containing $15-20\%$ inulin by fresh weight with a high degree of polymerization (DP $2-60$). It is widely utilized in functional dairy products as a prebiotic dietary fiber and fat replacer.
• Correct Option: Option 1 (Chicory root).