Food Engineering/Packaging & Labeling

• 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

• Packaging Film Thickness for Large Milk Pouches:
• Packaging Specifications:
• For retail milk pouches ($500\text{ mL}$ to $1\text{ L}$), co-extruded LDPE/LLDPE films of $55 - 65\ \mu\text{m}$ are standard.
• For bulk institutional milk pouches holding 6 liters, film mechanical burst strength requires high-density multi-layer co-extruded polyethylene film with a thickness of 120 microns ($120\ \mu\text{m}$) to withstand hydrostatic dropping shocks.
• Conclusion: 120 microns (Option 4).

Correct option: (4) 120 microns

• Barrier Layer in Aseptic Beverage Packaging (Tetra Pak):
• Aluminum Foil Barrier:
• Aseptic Tetra Pak cartons incorporate an aluminum foil layer to provide an absolute hermetic barrier against light, oxygen, and external vapors.
• Official Answer Key: Designated 0.09 mm (Option 1) as the credited answer.
• Conclusion: 0.09mm (Option 1).

Correct option: (1) 0.09mm