Dairy Packaging, Sensory & By-Products

Statement (I) is true: Homogenized milk has a greatly increased fat globule surface area and dispersed milk fat globule membrane components, making it highly susceptible to light-induced oxidation and 'sunlight flavour'; therefore, opaque packaging (paperboard cartons, pigmented bottles) is essential. Statement (II) is true: To minimize pressure pulsations and ensure uniform, steady milk delivery without cavitation, multi-plunger positive displacement pumps (typically 3 or 5 pistons/plungers) are standard in homogenizers.

Cellulosic packaging materials classification:

• Folding cartons are fabricated from flat paperboard sheets that are scored, cut, and folded.
• Beverage cartons (gable-top or aseptic bricks) are constructed from multilayer laminated paperboard.
• Vegetable parchment is chemical-treated cellulose paper used for butter wrapping.
• Moulded pulp (moulded fibre) is specifically defined as 3D articles produced by depositing suspended recycled or virgin cellulosic fibres from an aqueous slurry onto contoured screened wire moulds under vacuum suction, widely used for egg trays, fruit trays, and food service tableware.

Thermoforming and blister packaging materials:

• LLDPE is a flexible sealing film, lacking the rigidity needed for blister cavities.
• HDPE has poor clarity and difficult deep-draw thermoforming characteristics for blister pockets.
• Polyvinyl chloride (PVC), at sheet thicknesses of approximately $200\,\mu\text{m}$ ($0.2\text{ mm}$), is the industry standard thermoforming material for blister packaging due to its exceptional clarity, rigidity, ease of deep-draw thermoforming, and sealing affinity with aluminium lidding foil.
• PVDC is an ultra-high barrier polymer used as a thin coating ($2\text{--}5\,\mu\text{m}$), not an extruded monolithic $0.2\text{ mm}$ thermoformable sheet.